I

I, i ~· .

l. r r

' '

' ' ' I

i '

. WINTER 1979 ISSN 0020-6164

•

·' '• _,..., .. - I" !£.

MICROBIOLOGICAL CORROSION OF METALS- MARINE WOOD • ~ w

BORERS~ RODENT ATTACKS ON STOREO PRODUCTS- F-OULING OF SHIPS BY·BARNACLES- DETERIORATION OF STONE BY BACTERIA-·

·~~~~g~o~IL~~~I~G BciF ~~A~~1ER B~~~~~~~A~R:~:~g~~O~~ -BIRD: HAZARDS TO AIRCRAFTt:_ FUNGI IN JET FUEL .TANKS­TERMITES IN TIMBER - MICROBIOLOGICAL ATTACK ON RUBBERS - - ' - ~

PLASTICS AND PAINTS,- FUNGAL· ETCHING OF GLASS .....

'

. BIODETERIORATION • ' . ~ .

BuLLEtiN

A QUARTERLY JOURNAL·'OF BIODETERIORATION

1 ________ ---/

. '':lt

BIODETERIOJ3ATION CENTI3E

THE UNIVERSITY OF ASTON IN BIRMINGHAM

ENGLAND

..• -,..,,,A " ' . .....

'I ., •.:·- .

. ..

CATOMANCE LIMITED

manufacturers of

mystox* for the preservation of

timber, textiles paper, cordage

plastics and specialised applications

* mystox is the registered trade mark of

Catomance Limited 94 BRIDGE ROAD EAST, WELWYN GARDEN CITY,

HERTS., ENGLAND. Telephone: Welwyn Garden 24373/8

Volume 15 Number 4 Winter 1979

INTIRNATI

BUlliTIN CONTENTS

BIODETERIORA TION SOCIETY NEWSLETTER Forthcoming meetings 1980, Meetings in 1981 iii

Abstracts of some papers on Biocides for the Preservation of Materials iii Forthcoming conferences, meetings and courses vi

iii-vi

ISSN 0020-6164

A COMPARISON OF THREE SPECIES OF NASUTITERMES (Isoptera: Termitidae) AS TERMITES FOR LABORATORY BIOASSAYS

C.D. Howick and J.W. Creffield Comparaison de trois espl:ces de Nasutitermes (Isoptera: Tennitidae) comme termites pour essais biologiques de laboratoire.

Ein Vergleich von drei Nasutitermes-Arten {Jsoptera: Tenuitidae) als Priiftiere fur Laboratoriumsprlifungen. Estudio comparative de trcs especies de Nasutitermes (lsoptera: Tennitidae) como termitas para bioensayo

105-112

SOFT-ROT FUNGI FROM COPPER-CHROME-ARSENIC TREATED HARDWOOD TRANSMISSION POLES IN TASMANIA

M.A. line and R.H. Cruickshank Champignons de pourriture moUe isol~s de poteaux de transmissions traitt!s au Cuivre..Chrome-Arsenic en Tasmanie.

Moderiliulepilze aus CKA-benandelten Leitungsmasten auf Tasmanien Bongos causantes de ligcra podredumbre de pastes electiicos tratados con cobre-cromo-arsenico

113-118

A POSSIBLE METHOD FOR ENUMERATING BACTERIA IN WOOD Janice K. Carey.

Me'thode possible pour compter lcs bacteries dans le bois Ein mOglichcs Verfahren zur Ziihlung von Baktcricn in Holz. Un posible motodo para el recuento de bacterias en madera.

119-123

THE USE OF PITTING POTENTIAL TO STUDY THE MICROBIAL CORROSION IN 2024 ALUMINIUM ALLOY

R.C. Salvarezza, A.F.L. de Mele and H.A. Videla L 'utilization dele potentiet de rupture pour etudicr Ia corrosion microbiologique de l'alliage de l'aluminium 2024.

Die Bcstimmung des Lochfransspotcntial als Methode zu untersuchung dcr Mikrobiologische Korrosion der Aluminiumlegierung 2024. Uwo del potencial de picado para estudiar Ia corrosion microbiologica de la aleacion de alumino 2024.

125-132

BOOK REVIEWS

133-134

INDEX TO VOLUME IS

135-136

INTERNATIONAL BIODETERIORATION

BULLETIN

BIODETERIORATION CENTRE UNIVERSITY OF ASTON ST. PETER'S COLLEGE, SALTLEY, BIRMINGHAM B83TE.

Editor-in-Chief of Biodeterioration Centre Journals Dr. H.O.W. Eggins.

Editor Professor T.A. Oxley.

Business Manager Dr. D. Allsopp

The Editors are able to call upon the assistance of an Editorial Board whose members are in Britain, various countries of Europe, and the U.S.A.

NOTES FOR CONTRIBUTORS The International Biodeterioration Bulletin is

published four times per year (Spring, Summer, Autumn and Winter). Typescript contributions should be sent to the Editor, Professor T.A. Oxley, at the above address.

The Bulletin acts as a vehicle for the publication of original works, including reviews, on all aspects of bio­deterioration, i.e., deterioration of materials, artefacts or facilities, of economic importance by living organisms, which include microorganisms, insects, rodents, birds, higher plants, etc. Articles on biodegradation, that is conversion of materials to less objectionable, more easily disposable, or higher value products by living organisms, are also published.

Contributions are published only in English. Each article must be accompanied by a summary in 50-150 words which will be translated into French, German and Spanish. Native speakers of these languages are invited to submit their summaries in their own language; in certain circumstances complete articles may be sub­mitted in French, German or Spanish and will be trans­lated into English for publication.

Illustrations must be very clearly drawn, normally larger than the size finally desired. The suggested final size should be clearly indicated but the Editor reserves the right to vary this in the interests of economy and clarity.

As far as possible diagrams will be reduced to single column width (80 mm) or to half page (170 mm). In any event, neither these nor half tone photographs can exceed full page (260 by 170 mm). Authors should bear in mind that it is generally more convenient for readers if legends which accompany diagrams or photographs appear with them on the same page and should proportion their illustrations accordingly. Lettering on diagrams will normally be inserted by the printer; authors are therefore asked to insert lettering or symbols in pencil on the originals or in ink on a copy.

All articles are submitted by the Editor to one or more independent referees for advice on their clarity, originality, and general suitability for publication, but the final decision whether or not to publish an article rests with the Editors. If articles are rejected the sub­stance of the referee's report will usually be communic­ated to the author and in suitable cases the Editor will be pleased to help authors to improve their pages with a view to possible publication.

The bibliographic references are. to be indicated in the text by the author names (without initials) and year only, viz:

Reese and Levinson (1952), or Darby et at., (1968) and in the bibliography:

Reese, E.T. and Levinson, H.G. (1952). Comparative study of the breakdown of cellulose by micro­organisms. Physiol. Plant. 5, 354-366.

or Darby, R.T., Simmons, E.G. and Wiley, B.J. (1968). A

survey of fungi in a military aircraft fuel supply system. Int. Biodeterior. Bull. 4, (1) 39-41.

References to books, conference proceedings etc., should quote first the author(s) or editor(s). then the year of publication and title followed by the publisher's name and the city in which published. Titles of journals should be abbreviated according to the convention of the World List of Scientific Publications and underlined {for reproduction in italics). Volume numbers should be double underlined (for reproduction in bold type) and if possible the part number should be given in brackets.

20 reprints will be sent free of charge to the first named author unless otherwise instructed. Any number of additional reprints may be purchased if ordered in advance. An order form and quotation of price will be sent giving about one month's notice about the time that galley proofs are received from the printer.

ACKNOWLEDGEMENTS TO SUSTAINING ORGANISATIONS

Financial support for the Biodeterioration Centre from the following organisations is gratefully acknowledged: ALBRIGHT & WILSON (MFG} LTD., CIBA-GEIGY LIMITED,CH4002 Basle microbiology and microbiological

0/dbury Division, P.O. Box 3, Switzerland; manufacturers of dye~ deterioration. Oldbury, Warley, Wares., England. stuffs, industrial chemicals, plastic

B.D.H. CHEMICALS LIMITED, Lab· oratory Chemicals Division, Poole. Dorset, England; manufacturers of laboratory chemicals, biochemicals, industrial fine chemicals and micro­biocides.

BRITISH INSULATED CALLENDERS CABLES LIMITED, 38 Wood lane, Landon, W12, England.

BP CHEMICALS INTERNATIONAL LIMITED.

CATOMANCE LIMITED, Walwyn Garden City, Hertfordshire, England; manufacturers of speciality chemicals for the textile, paper, timber, leather industries, etc., including fungicides, bactericides and insecticides.

additives, photochemicals, pharma­ceutical and agricultural chemicals.

COURTAULDS LIMITED, Warwickshire, England.

Coventry,

FARBENFABRIKEN BAYER A.G., Leverkusen, Germany; manufacturers of dyestuffs, industrial chemicals, synthetic fibres, pharmaceutical and agricultural chemicals and preserva­tives for wood, foodstuffs and technical products.

STERLING INDUSTRIAL LIMITED, Chapeltown, Sheffield, England.

HALDANE CONSULTANTS LIMITED, 27 Dawkins Road, Poole, Dorset, BH15 4JB; consultants in industrial

ii

HICKSON & WELCH (HOLDINGS) l TO., lngs Lane, Castleford, York­shire, England.

IMPERIAL CHEMICAL INDUSTRIES LIMITED, Agricultural Division, Billingham, Co. Durham, England.

LUCAS AEROSPACE LTD., Shaftmoor Lane, Birmingham, England. B28 SSW.

NATIONAL COAL BOARD, Coal House Lyon Road, Harrow, Middlesex, England.

AENTOKIL LIMITED, East Grinstead, West Sussex, England.

AEVERTEX LIMITED, Harlow, Essex, England.

Biodeterioration Society Newsletter (3/4) 1979 Int. Biodeterior. Bull. (ISSN 0020-<5164) IS (4) 1979.

BIODETERIORATION SOCIETY NEWSLETTER

Forthcoming meetings 1980

I. Joint meeting with the British Ecological Society 31st May 1980 at St. Peter's College, University of ASTON, Birmingham.

Theme: "Use of cotton strips for measuring cellulose decomposition".

2. Annual Summer Meeting, lOth and lith July 1980 at Preston Polytechnic.

Theme: "Biodeterioration of Polymeric Materials".

3. Autumn meeting, lith December 1980 at Building Research Establishment (Princes Risborough Lab­oratory).

Theme: "Effect of Toxic Chemicals on Microbial Ecology".

Meetings in 1981

I. Joint meeting with the Institute of Petroleum, Spring 1981. London.

Theme: "Physical Methods for Control of Biodeterioration".

2. Annual Summer Meeting, July 1981 at Portsmouth Polytechnic.

3. Sth International Biodeterioration Symposium, Kings College, Aberdeen, Scotland, 6-12 September, 1981.

Abstracts of some papers presented at a meeting of the Biodeterioration Society

under the general title of

BIOCIDES FOR THE PRESERVATION OF MATERIALS held at the Hatfield Polytechnic

on Tuesday and Wednesday 18th and 19th December 1979

Title: Structural activity relationships fungicidal compounds.

Author: RJ. Cremlyn

Address: School of Natural Sciences (Chemistry) Hatfield Polytechnic, College Lane, Hatfield, Herts. ALI09AB.

ABSTRACT

of

The lecture covered the major types of organic surface fungicides: the dithiocarbamates and the N-trichloromethyl sulphenyl compounds, their uses and mode of action. The systemic fungicides: oxathiins, pyrimidines, benzimidazoles, organa­phosphorous compounds and antibiotics were also covered. New developments mentioned included systemic fungicides active against phycomycete fungi: furalxyl, metalaxyl, and aluminium ethyl­phosphite. The problems of resistant fungi were

iii

mentioned. Since these have arisen particularly with respect to the use of systemic fungicides, there is a continued need for the introduction of new surface fungicides such as chlorothalonil, vinchozolin and iprodione.

Biodeterioration Society Newsletter 1979 No. 3/4.

Title: The preservation of fuel oil systems.

Author: B. Cook.

Address: Microbiology Research, School of Natural Sciences, C.P. Snow Building, Hatfield Polytechnic, College Lane, Hatfield, Herts. AL109AB.

ABSTRACT

Cladosporium resinae, a major deteriogen of jet aircraft fuel, has also been found to cause problems in marine gas turbine systems. Biocidal control at present is by the use of organo-borons at 270 ppm for disinfection and 135 ppm for continuous dosage. However, these doses have been proved to be fungistatic only and the efficiency of organo-borons is greatly reduced at lower oil:aqueous ratios. Benomyl has been found to control growth at con­centrations as low as 1 ppm. At 20 ppm benomyl was found to kill hypha! growth within 24 hours, a slide culture method being used to observe the biocidal effects on the hyphae. At 20 ppm however, benomyl proved to be only fungistatic after 5 weeks on spores sampled both at the oil-aqueous interface and within the whole aqueous phase, but at the inter­face a reduction in the total number of viable spores was noticeable.

Title: Biocides from Sterling Industrial

Author: G.R. lloyd.

Address: Sterling Industrial, Microbiology l..aboratmy, Izal Ltd. Chapeltown, SHEFFIELD.

ABSTRACT

In the past I 2 months Sterling Industrial has initiated a customer senjce laboratory designed to provide assistance to those in industry not fortunate enough to have the necessary facilities.

Samples of cutting fluid are analyzed regularly to determine the degree of microbial contamination after which help and advice is given to try to reduce the massive cost to the industry of microbial degradation.

Many branches of industry have so far made use of the services including those working with paints, oils, soaps, textiles, inks and, in fact, any area that involves the use of aqueous emulsions.

iv

Title:

Author:

The effectiveness of biocides applied to masonry surfaces.

A.O. lloyd.

Address: 24, Rooks Hill, Welwyn Garden City, Hertfordshire, AL86ET.

ABSTRACT

Situations in which biocides fail to control growths, namely excessive dampness with a well established lichen vegetation, were described. The anomaly that lichens are extremely sensitive to atmospheric pollution yet some are able to resist biocidal washes was shown to be due to the different structure and exposure or foliose, fruticose, and crustose types, the latter being resistant. The mechanism of resistance to biocides was described. The types of deterioration caused by lichen and algae were reviewed.

(Editor's summary based on notes provided by the author).

Title: Practical considerations in water-based cutting fluids.

Author: D.A. Hope.

Address: B.P. Oil Ltd., B.P. House, Victoria Street, LONDON SWlE 5NJ.

ABSTRACT

Water-based cutting fluids suffer gross abuse in service and microbial growth of essentially non­pathogenic species causes foul odours, corrosion and blocked pipes and filters. Biocides currently provide the only effective remedy and the relative merits of continuous use, shock treatment, in-service addition, and incorporation in the concentrate were discussed. Biocides must be compatible with, and retain activity in, formulations; they must not reduce corrosion protection or be skin irritants or sensitizers. Expensive testing to ensure this leaves few viable alternatives. Continuing work will seek ecologically acceptable, more bioresistant formulations, safer and more effective biocides and improved education of users.

Biodeterioration Society Newsletter 1979 No. 3/4.

_.,... Title: r Biocides for the preservation of textiles

Author: A.R.M. Barr

Address: Catomance Ltd., .._ 88/96 Bridge Road East,

Welwyn Garden City, Herts. AL71JW.

ABSTRACT

Textiles made from natural fibres,- cotton, flax, jute , hemp, wool and silk - are susceptible to deterioration by microorganisms. Fungi are the principal agents responsible for this damage; many cellulolytic species inhabit the soil and are therefore readily available to contaminate and attack textile materials. Mould growth is favoured by high humidity, moderate temperature and diminished light. When this combination of conditions is achieved a susceptible material is readily decayed. To minimise this type of deterioration ehernical treatments are continually being developed to control microbial populations. The advantages and dis· advantages associated with preservatives as cited in BS2087 were discussed. The importance of demonstrating that the active constituent of a treatment is not harmful to the environment was stressed.

Title: The use of preservatives in the oil recovecy industcy.

Author: Stuart Wing.

Address: lCl Organics Division, Blackley, MANCHESTER.

ABSTRACT

The need for effective biocides is already widely recognised in the oil recovecy industl}'. Fluids used in drilling operations, which often contain poly· saccharide ingredients, are especially prone to micro· bial attack with accompanying changes in physical properties.

The conditions encountered in oil storage tanks can lead to the growth of sulphate reducing bacteria which cause odour and corrosion problems.

As world oil prices continue to rise, there is increasing emphasis on improved oil recovecy techniques. Such techniques will involve flooding of wells with water or aqueous polymer solutions. Although these methods are relatively new, it is already known that biocides are needed to prevent the spoilage and corrosive effects of bacteria. As well as providing the required technical effect, it is also essential that any biocide should have minimum effect on the environment.

v

Title: The use of an oxygen electrode to assay some biocides.

Author: L.H.G. Morton.

Address: Division of Biology, Preston Polyteehnic, Corporation Street, PRESTON PRJ 2TQ.

ABSTRACT

Oxygen electrode studies have been undertaken with a view to using this technique more widely in assaying potential biocides. The effect of bis(tributyltin) oxide upon the respiratol}' activity of five wood-inhabiting fungi was presented. The oxygen electrode employed in the investigation was described together with an account of the practical laboratol}' procedures involved.

Title: A review of synthetic pyrethroids for the protection of wool and wood.

Author(s): G.D. Dodd and S.W. Carter.

Address: The Wellcome Foundation Ltd., Crewe Hall, Crewe, Cheshire.

ABSTRACT

The development and properties of the photo­stable pyrethroids were reviewed with particular reference to permethrin and its use in the fields of wool and wood protection. The influence of dye· bath pH, dyeing auxiliaries and duration of boiling in the dyebath on the application of perrnethrin as aidndustrial mothproofer for woollen based products was discussed. The compound shows excellent fastness on wool and good biological activity against the major textile pests. The low residue levels in effluent following application of perrnethrin are unlikely to pose any hazard during disposal. Application rates were given for perrnethrin as an insect-proofing agent for yam destined for carpets and other products.

The activity of the synthetic pyrethroids against important wood-boring beetles and marine crustaceans was compared with existing wood preservative agents. The stable pyrethroids make prime contenders for wood preservation having a broad spectrum of insecticidal activity, good persistence in wood, low mammalian toxicity and low environmental hazard.

Biodeterioration Society Newsletter 1979 No. 3/4.

FORTHCOMING CONFERENCES, MEETINGS AND COURSES

Date

6-8 February 1980 19SO

25-26 March 1980

25-27 March 1980

7- October,l980 4- 6 November 1980

15-17 Apri11980

12-15 May 1980

31 May 1980

June 1980

28-30 July 1980

7-12 Sept. 1980

8-12 June 1981

6-12 Sept.l981

Subject and· Title of Meeting

Industrial Waste 3rd. International Congress on Industrial Waste Water and Wastes (Sponsored by IUPAC)

Biodeterioration International Biodeterioration Research Group (IBRG) Spring meeting The following groups will meet:­Paints, Construction Materials, Taxonomy/Ecology, Cutting Oils, Industrial Problems.

Control of Insects and Rot in Buildings Three Day Course Fee:-£29.75 incl. VAT

Livestock Wastes 4th International Symposium on Livestock Wastes

Grain Storage International Symposium on Controlled Atmosphere Storage of Grains Fee:- Lit 25,000.

Cellulose Decomposition Discussion meeting on the use of Cotton Textile Strips for Measuring Cellulose Decomposition (Joint meeting, Biodeterioration Society and British Ecological Society).

Marine Corrosion and Fouling 5th International Congress on Marine Corrosion and Foulding

Controlled Release of Bioactive Materials 7th International Symposium on Controlled Release of Bioactive Materials

Macromolecules IUPAC International Symposium on Macromolecules

Rubber International Rubber Conference and Exhibition 'Rub hereon '81'

B,iodcterioration 5th International Biodeterioration Symposium

vi

Location

Stockholm SWEDEN

Aberdeen SCOTLAND

Princes Risborough (Near Aylesbury) ENGLAND

Amarillo, Texas, U.SA.

Castelgandolfo, Rome, ITALY.

Birmingham ENGLAND

Barcelona SPAIN.

Ft. Lauderdale, Florida, U.SA.

Florence ITALY

Harrogate, ENGLAND.

Aberdeen SCOTLAND.

Contact

Box 21060 s-100 31, Stockholm, SWEDEN.

Dr. J.M. Shewan, 79, Duthie Terrace, Aberdeen, SCOTLAND. Phone: 0224 37565

Miss Diane Poole, Building Research Establishment Princes Risborough, AYLESBURY, Bucks. HP17 9PX. Phone: 084 44 3101.

A.SA.E. Box 410 St. Joseph, Mich. 49085, U.SA.

Dr. J. Shejbal, ASSORENI 00015, Monterotondo, Roma, ITALY.

Dr. D. Walton, British Antarctic Survey, Madingley Road, CAMBRIDGE, CB3 OBT. Phone: 022:1;1188 ext. 255.

Secretaria del Congreso, Revista ''CP Corrosion y Proteccion" Calle Londres 17 MADRJD-28, Spain.

Dr. Danny H. Lewis, Southern Research Institute, 2000 Ninth Avenue South, Birmingham, Ala. 35205, U.S.A.

F ondazione Giovanni Lorenzini Via Monte Napoteone 23 20121 MILAN Italy. Phone: (02) 702.267

or 783 868 Richard H. Craven, Plastics and Rubber Institute, 11, Hobart Place, London SIV I W OHL.

Dr. J .M. Shewan, 79, Duthie Terrace, ABERDEEN Scotland. Phone: (0224) 37565.

Int. Biodeterior. Bull. ISSN 0020-6I64 15 (4) 1979. (105-112)

A COMPARISON OF THREE SPECIES OF NASUTITERMES (ISOPTERA: TERMITIDAE)

AS TERMITES FOR LABORATORY BIOASSAYS C.D. Howick1 and J.W. Creffield1

Summary. Numerous laboratory bioassays have been carried out in Australia with Nasutitermes exitfosus (Hill) but it is t11e only representative of the genus to have been used for this purpose. Two other species, N. gra~•elous (Hill) and N. walken· (Hill) were therefore tested to see if their laboratory adaptability and performances were as favourable as those of N. exitiosus.

Replicate 10 g groups of the three termite species were fed on untreated specimens of the wood of Ceratopetalum apetalr&m D. Don and Eucalyptus regnans F. Muell. at 32°C and 26°C. Unfed control groups were also installed. To obtain sequential mass loss data, all timber specimens were removed and weighed after 4 and 8 weeks before being returned to complete a 12 week incubation period.

The investigation showed that N. graveolus may be a suitable species for laboratory bioassays at either temperature and that increased feeding could be anticipated at 32°C. Results with N. walkeri indicate either that its potential as a laboratory bioassay insect may be limited to tests of short duration or that the timbers tested are less susceptible to this species.

Comparaison de trois espCces de Nasutitermes (fsoptera: Termitidae) comme temites pour essais biologiques de laboratoire. De nombreux essais biologiques de laboratoire ont CtC effcctuCs en Australie avec Nasutitermes exitiosus Hill mais c'est le seul representant du genre a avoir ete utilise pour ce but. Deux autres especes, N. graveolus (Hill) et N. walkeri (Hill) ant cependant ete essay€s pour voir si leur adaptation et leurs performances en laboratoire sont aussi bonnes que cellcs de N. e.xitiosus.

Des se"ries de groupes de 10 g des trois espCces de termites ant ete alimentCs d'€chantillons de bois non trai(e de Ceratopetalum apelatum D. Don et d'Eucalyptus regnans F. Muell. a 32° et 26°C. Des groupes temoins non alimentSs furcnt aussi mis en place. Afin d'obtenir des donnees en pertes de masse sequentielles, taus Ies Schantillons de bois furent enlcves et peses apres 4 et 8 semaines avant d 'etre remisen place pour terminer une pc!riode d'incubation de 8 semaines.

Les recherches ont montre que N. graveolus peut convenir pour les essais biologiques de laboratoire aux deux temperatures et que l'on pcut pcnser que l'alimentation est augment€e a 32°C. Les rSsultats avec N. walkeri indiquent que son aptitude potentielle comme insecte de laboratoire d'essais biologique peut ~tre limit€e a des essais de courte dur"ee on que les bois essayes sont moins sensibles a cettc espece.

Introduction

In Australia, standard techniques for laboratory assessments with tennites have been established for more than twenty years (Gay eta/. !955). During this period, at least 15,000 jar bioassay groups have been set up, with some 300 kg of tennites being used at the CSIRO Divisions of Entomology and Building Research. The species of tennites used have been Coptotennes

Ein Vergleich von drei Nasutitermes-Arten (Jsoptera: Termitidae) als Pruftiere fur Laboratoriumsprufungen. In Australien sind zahlreiche biologische Pr'Urungen mit Nasutitermes exitiosus (Hill) durchgefuhrt worden. Da diese Art der einzige Vertreter dieser Gattung ist, der fiir diese Prufungen benutzt wurde, wurden mit zwei anderen Arten, d.h. mit N. graveolus (Hill) und N. walkeri (Hill) Untersuchungen vorgenommen, urn zu ermitteln, ob ihre Verwendbarkeit fiir Laboratoriumsversuche und ihr Verhalten iihnlich gunstig wie das von N. exitiosus ist.

Vergleichbare Gruppen von jeweils 10 g der drei Termitten­arten wurden auf unbchandelten Holzproben von Ceratopetalum apetalum D. Don und Eucalyptus regnans F. Muell. bei 32°C und 20°C geziichtet. Versuche mit nicht gefiitterten Kontroll­gruppen wurden ebenfalls angesetzt. Die Versuchsdauer betrug insgesamt 12 Wochen, wobei die Holzproben nach 4 und 8 Wochen entfernt und gewogen wurden, urn eine Reihe von Werten uber den Gewichtsverlust zu erhalten.

Die Untersuchung ergab, dal1 N. graveolus m'6glichenveise als Prufticr fiir Laboratoriumsuntersuchungen bei heiden Temperaturen angesehen werden kann und dal1 bei 32°C eine erh&hte FraBaktivittit erwartet werden kann. Ergebnisse mit N. walkeri zeigten, daB diese Art als Laboratoriumspruftier nur lur Kurzpriifungen geeignet ist oder da11 die geprUften Holzarten weniger anr3.11ig gegeniiber dieser Art sind.

Estudio comparative de tres especies de Nasutitermes (lsopteratermitidae) como tennitas para bioensayo. Numerosos bioensayos han sido realizados en Australia con Nasutitermes exitiosus (Hill) perc es el unico representante usado para este proposito. Otras dos especies N. graveolus (Hill) y N. walkeri (Hill) fueron en consecuencia probadas para ver si su adabtabilidad y actuacion cran tan favourables como las de N. exitiosus.

Varies grupos de 10 g. de las tres termitas fueron alimentadas sobre muestras de madera de Ceratopetalum apetalum D. Don y Eucalyptus regnans F. Muell. a 32°C y 26°C. Y como control se utilizaron grupos no alimentados. Se retiran todas lass muestras de madera y se pcsan a 4 y 8 semanas antes de completar 12 semanas de incubacion, para obtener datos de peridas de masa.

La especie N. graveolus puede ser apropiada para el ensayo biologico en el laboratorio a cualquiera de las dos temperaturas y incremento de alimentacion puede ser anticipada a 32°C. Los resultados obtenidos deN. walkeri indican que su potencial como insecta de ensayo biologico en el laboratorio puede ser Umitada para cnsayos de corta duracion o que las maderas scan menos susceptibles a estas especie.

lecteus (Froggatt), Coptotennes acinacifonnis (Froggatt), Nasutitennes exitiosus (Hill) and more recently Mastotennes danviniensis Frogatt (cf. Gay and Wetherly 1958, 1971, Gay et a/. 1958, Hawick and Creffield 1975,Howicketa/.,1975).

In assessing the termiticidal efficacy of wood preservatives or the natural resistance of timber species, Australian practice has usually been to use two or more

1CSIRO Division of Building Research, Forest Products Laboratory Highett, Victoria, Australia.

(Received, June 1979).

105

A comparison of three species of Nasutitemzes ( lsoptera : Termitidae) as Termites for Laboratory llioassays, C.D. Howick and J .W. Creffield.

termite species having physiologically different digestive systems (e .g. Rudman and Gay 1964. Gay and Evans 1968. Da Costa et a/. 1971 . 1 chanson and llowick 1975). TilUs, one species has been of the genus Coptotennes, known to contain a large protowan gut fauna as well as bacteria (Sutherland 1933. Da Costa et at. 1975) and the other has been of the genus Nasutitennes, which depends on intestinal flora for digestion (Lee and Wood 1958, :-Joi rot and Noirot · Timothee 1969, French 1975).

Use of the two species of Coptotermes responsible fo r damage to timber in buildings has often shown up differences in preservative efficacy or the susceptibility of certain wood species. No such comparisons have been made within the genus Nasu riremzes. Because of the extensive amount of laboratory assessments carried out with V. exitiosus. much is known of its feeding capacity, food preferences and susceptibility to preservatives (Gay et a/. 1955 ). It is widely distributed in Australia but mounds are often large , heavy . constructions set quite deep in the ground and field collection for laboratory bioassays is sometimes difficult .

Of the remaining 18 species of Nasutitemzes reported to occur in the Australian region , many are mound­building grass feeders (Gay and Calaby 1970). Only two of the wood feeders which also attack timber in buildings. N. grat'eolus (I WI) and N. walkeri (I !ill) of the NE costal regions arc common and easily collected . TI1e arboreal nests are of comparatively small size (up to 300 450 mm diameter) but are densely populated and the internal carton is of a comparatively delicate nature . They are often found on small . easily felled trees (Figure J ).

A series of bioassays was therefore carried out to compare the feed mg capacity in the laboratory of .V. grm,eolu~ and N. walkeri with that of N. exitiosus.

Materials and Methods

Tennires During routine field collections, colonies of N.

gra11eo/u.l· and N. walkeri were located in northem and southern Queensland respectively. The trees to which the colonjes were attached were felled and termites were sifted and separated from the nest material .

Termites from each species collected were than allocated to I litre glass jars in estimated 50 g groups for transportation and maintenance. Each jar contained a specimen of Eucalyptus regnans F. Muell . heartwood (15 x 25 x 100 mm) for food,in a moist matrix (Howick 1978). On arrival at our Melbourne laboratory. all jars were stored in a controlled insectary at 26°C, 80% R.l l. until used in the assessment.

TI1e N. exiriosus were obtained from a colony in the ground at Seymour. Victoria and separated by the usual techniques (Gay eta/. 1955). TI1ese tennites were also allocated to I litre ja rs in 50 g groups and stored as described above until used in the assessment.

106

I J

Figure 1 . Arboreal nests of N. walkeri on small eucalypt trees in Queensland.

Timbers For the assessment of the comparative feeding

capacity of the three species of Nasutitermes, it was decided to usc two different wood species. TI1e inability of N. exitiosu.s to attack Pinus species is well known and is probably due to the fact that pinene forms part of the insect's alarm pheremone (Moore 1964 , Lee and Wood 197 1 ). liard woods were therefore selected and these were F:. reg11ans (Mountain ash) highly susceptible to termites . and Ceratopetalum ape tatum D. Don (Coach wood) a less dense species, frequently used in previous bioassays and shown to be susceptible to N. exitiosus but slightly less so than F:. regnans (Gay et at. 1955).

For each species . specimens (I 5 x '25 x 100 mm) were cut from strips of equal radial position in a single representative heartwood board .

Temperatures Because of the northerly occurrence of N. graveolus

and N. walkeri (IIill 1942), it was decided to compare the laboratory perfom1ance of all three species of Nasutitemzes at 32°C with that occurring at 26°C. the temperature more commonly used for laboratory assessmcn ts.

The Bioassay Termites were separated from the holding jars and

pooled accordffig to species. Specimens of each of the

A comparison of three species of Nasutitermes (Isoptera: Termitidae) as Termites for Laboratory Bioassays, C.D . . Bowick and J .W. Creffield.

Figure 2. Standard bioassay jar colony showing vermiculite canopy built by the termites over the wooden specimen.

two timbers were separately exposed to five 10 g replicates at each of the two temperatures in a standard bioassay test (see below and Fig. 2). Replicates of unfed 10 g groups were also installed at each temperature to compare their vitality. As a result of previous laboratory investigations (llowick 1975, 1978 , Howick and Creffield 1979), the following experimental layout and conditions were adopted:

Termite species

Group mass Matrix (a)

(b) Moisture (a)

(b) Temperature !tumidity Containers Ventilation

Type Amount per jar Percentage Amount per jar

Specimen (a) Species (b) Size

No. of jar replicates Assessment period

N. graveolus. N. exitiosus, N. walkeri

lOg Grade 4 vermiculite 70 g 250% 175 ml 26°C and 32° C 80% R.H. I litre glass jars Vented lid (9 mm) 1~·. regnans, C. apetalum 15 X 25 X I 00 mm 5 4 , 8 and 12 weeks.

and 84 days. At these times, specimens were removed from the jars, cleaned and then oven dried at 105"C for 5 hours. After weighing, each specimen was momentarily dipped in water and returned to the appropriate jar at which time no specimens were rejected by termites, and within a few days the canopy of venniculite built around the top portion of the specimen was rebuilt (Fig . 2).

Results

Feeding Basic details of feeding are shown in Table I.

Although feeding by groups of N. graveolus and N. exitiosus was similar during the 0 4 and 4-8 week periods , amounts of wood eaten during the final 4 weeks of the test were considerably lower for N. exitiosus. However, feeding by N. walkeri decreased slightly in. the 4- 8 week period and markedly during the final 4 weeks, possibly indicating unsuitability of both timbers to tltis species.

Feeding activity, as determined by the proportion of wood eaten by the termites, was further studied by considering the cumulative proportion of wood eaten at the end of the 4, 8 and 12-week periods . The results were assessed by analysis of variance in arc sine s4uare root transformation and are summarised in Table 2.

TI1e effect of temperature can be more readily interpreted by reference to the statistical data. For N. graveo/us it is clear that greater feeding activity occurs at 32°C than at 26°C for both C. apetalum and F:. regnans. The same applies to a lesser extent for N. exitiosus but not for N. walkeri. However , when freed from the effects of timber and tennites , increased feeding occurs at the higher temperature.

The effect of timber species is significant only in the 0 4 week period, during which the proportion of mass loss in the F:. regnans specimens is significantly larger than that in C. apetalum.

l11e feeding activity of N. graveolus and N. exitiosus is similar except at 26°C during 0-8 weeks and at 32°C during 0 - 12 weeks. However, when freed from the effects of temperature and tin1ber there are no real differences in the proportion of wood eaten by these species , which in all cases is significantly higher than by N. walkeri.

Survival Details of termite survival during the 12-week test

period are shown in Table 3. The number of days after installation at which complete death of the groups occurred is given for each of the three termite species at each of the two temperatures .

It can be seen that aU fed groups of N. graveolus and N. exitiosus survived for longer than 12 weeks with the exception of two N. exitiosus groups at 32°C on C.

To measure the feeding activity of the three tennite apetalum which died at II weeks. However , the species, the timber specimens were weighed at 28 , 56 majority of the N. walkeri groups died after 7- 10 weeks

107

Termite species

N. exitiosus

-0 00 N. graveolus

N. walkeri

Table I

Grams of wood eaten in successive four-week periods by 10 g groups of three species of Nasutitennes at two temperatures (Mean of 5 replicates)

Incubation period

Timber species Temp. 0 -4weeks 4-8 weeks 8- 12 weeks (C)

C. apetalum 32 4.26 (0.28) 3.58 (0.40) 1.39 (0.02)

26 3.27 (0.14) 3.33 (0.13) 1.89 (0.12)

E. regnans 32 4.31 (0.17) 3.74 (0.13) 1.78 (0.25)

26 3.45 (0.08) 3.57 (0.02) 1.95 (0.07)

C. apetalum 32 4.34 (0.08) 4.05 (0.10) 4.20 (0.12)

26 3.05 (0.05) 2.50 (0.05) 2.34 (0.11)

E. regnans 32 4.16 (0.11) 3.43 (0.08) 3.00 (0.14)

26 3.02 (0.13) 2.26 (0.09) 1.92 (O.D7)

C. apetalum 32 3.31 (0.22) 2.02 (0.20) 0.63 (0.26)

26 3.03 (0.12) 2.34 (0.15) 1.31 (0.23)

E. regnans 32 3.31 (0.25) 1.31 (0.38) 0.30 (0.19)

26 2.39 (0.34) 1.49 (0.43) 0.44 (0.18)

The figures in brackets are the standard errors of the means

Total 12 weeks

9.24 (1.09)

8.48 (0.31)

9.82 (0.45)

8.97 (0.10)

12.59 (0:22)

7.89 (0.14)

10.59 (0.24)

7.20 (0.27)

5.95 (0.62)

6.67 (0.46)

4.93 (0.77)

4.32 (0.94)

:t;J> 0 " :!i. 0 "3 ...-., ..., ..., = :::;!. "'~ ._.o :,;;= . 0 n""" a;. ....,~

""" " " ""~ "" ~· ~

0 ...., ~ !:! ~

~·

~ ~ ~

:;;' 0

~ Pl

(;l

[ 0: l'l ~ ..., ~

(;l

~· " ~ 0' ~

~ 2 ~ 0 ~

"' ~ ~

~ ("}

b

A comparison of three species of Nasutitennes (Isoptera: Termitidae) as Termites for laboratory Bioassays, C.D. Hawick and J .W. Creffield.

and this is reflected in the feeding figures for that species. during the fmal4-week period (Table 1 ).

Survival times for · the unfed groups provide an indication of the normal death rate by starvation as well as a measure of the vitality of the termites used in the assessment. Reference to Table 3 will show that these times were quite regular, with N. graveolus and N. walkeri being almost identical and N. exitiosus lasting somewhat longer but consistent with times observed in other experiments with that species in a vermiculite matrix. (Hawick and Creffield, 1975).

Discussion

New information concerning the potential of N. graveolus and N. walkeri has been obtained during tltis study. Furthermore, broader issues concerning laboratory bioassays with these and other termite species may be raised as a result of some of the data.

The amounts of E. regnans eaten by the N. exitiosus groups at 26°C were comparable with amounts eaten in a similar assessment when the termites had also been maintained in 50 g lots for 28 days prior to the test (Hawick 1978). During that assessment, a similar sharp decline in feeding was also observed during the 8-12 week period and is a general phenomenon of termite bioassays (Becker 1969, Becker and Lenz 1970). As feeding and survival figures for N. exitiosus groups in the test described in this paper were consistent with those obtained in other bioassays conducted at this laboratory, direct comparison of the three Nasutitennes species is feasible.

The performance of N. walkeri under the conditions of this study was such that it cannot yet be recommend­ed as a satisfactory bioassay insect, particularly for tests in excess of 8 weeks duration. Even though unfed groups survived for a similar period to those of N. graveolus. indicating comparable vitality and adaptability, insufficient numbers of those exposed to the timber specimens survived for significant feeding during the 8-12 week period. The possibility that this is an effect of timber species requires further investigation.

The performance of N. graveo/us, however, was most encouraging. It appears to be a species capable of adaption to the disruption of field collection, laboratory handling and bioassay conditions. There was very little variation between replicates for amounts of wood eaten or survival of unfed groups at either temperature. That this tropical termite survived slightly longer at 26°C when starved, may be explained by a slight reduction in metabolism and general activity at the lower temperature. At 32°C, total wood consumption over 12 weeks was higher than for N. exitiosus. However, if laboratory facilities were restricted to 26°C, as most commonly used for termite bioassays in Australia, N. graveolus would still be satisfactory, and at that temperature the lower mass losses which occur are similar to those with N. exitiosus. On the basis of this study, it appears that bioassays of up to 12 weeks

109

duration with N. graveo/us would provide reliable results. It will now be necessary to assess all three species comparatively under stress conditions of feeding on preservative treated and resistant timbers. Their potential usefulness for laboratory bioassays will then be more readily determined.

An interesting finding concerns the comparative susceptibility of the two timber species used in this study. Only during the initial 4 weeks of the test was the proportion of mass loss in C. apetalum significantly smaller than in E. regnans (Table 2). Thereafter, there was no significant difference between the timbers. Considering the fact that all termites had initially been fed on E. regnans after field collection, this raises the question as to whether the timber species on which termites are maintained prior to bioassay tests, in any way affects their subsequent food preferences and if so, for what period. The influence of such an effect on the accuracy of laboratory bioassays with termites could be of considerable importance. Further investigations into this hypothesis have therefore been initiated.

Acknowledgements

The authors ackoowledge the cooperation and assistance of: (a) R.A. Barrett, CSIRO Division of Entomology -

for providing details of termite tests carried out at that Division since 1955 and for his assistance with collection of N. graveo/us.

(b) Dr. V.N. Reddy, CSIRO Division of Mathematics and Statistics - for statistical analyses and advice.

References

Becker, G. (I 969). Rearing of termites and testing methods used in the laboratory. In: "Biology of Termites" (K. Drishna and F.M. Weesner, eds), Vol. I, pp. 351-385. Academic Press, N.Y. and London

Becker, G. and Lenz, M. (1970). Vermiculit als Baden­material flir Versuche und Priifungen mit Termiten. Mat. und Org. 5,129-157.

Da Costa, E.W.B., Gay, F.J. and Osborne, L.D. (1971). Laboratory evaluations of wood preservatives. V. The effectiveness of some Austraiian creosotes against subterranean termites. Holzforschung 25, 43-47.

Da Costa, E.W.B., Hawick, C.D. and Lenz, M. (1975). Termiticidal effects of arsenic in association with phosphate. Mat. und Org. 3, 363-376.

French, J.R.J. (1975). The role of termite hindgut bacteria in wood decomposition. Mat. und Org. 10, 1-13.

Gay, F.J. and Evans, R.W. (1968). The status and termite durability of northern cypress pine. Aust. For. 32,80-91.

A comparison of three species of Nasutitermes (Jsoptera: Termitidae) as Termites for Laboratory Bioassays, C.D. Howick and J.W. Creffield.

Table 2

Cumulative percentage mass loss in specimens of C. Apetalum and E. Regnans at successive four-week intervals by I 0 g groups of three species of Nasutitermes at two temperatures

Termite species Timber species Temp. ("C) 0 -4weeks 0-8 weeks 0 - 12 weeks

N. exitiosus C. apetalum 32 19.9 36.7 43.4

26 !53 30.8 39.6

E. regnons 32 23.8 44.5 543

26 18.1 36.9 47 .I

N. graveolus C. apetalum 32 20.5 39.6 59.5

26 14.2 25.9 36.8

E. regnans 32 22.2 40.4 56.5

26 17.5 30.6 41.8

N. walkeri C. apetalum 32 114.9 124.1 126.8 26 14.1 24.9 30.9

E. regnans 32 17.2 23.8 125.2 26 12.7 203 22.5

Both woods Mean for N. exitiosus 119.3 137.2 146.1 and Mean for N. graveo/us 18.6 34.1 48.7

temperatures Mean for N. walkeri 14.7 233 26.4

3 termites Mean for C. apetalum 16.5 130.3 139.5 and both Mean for E. regnons 18.6 32.8 41.2

temperatures

Both woods Mean for 32°C 19.8 34.9 443 and three Mean for 26°C 153 28.2 36.5 termites

32°C 26°C 32°C 26°C 32°C 26°C

Mean for N. exitiosus 121.9 116.7 140.6 33.9 48.9 143.4 Both woods Mean for N. graveolus 21.4 15.9 40.0 28.3 58.0 393

Mean for N. walkeri 16.1 13.4 24.0 22.6 26.0 26.7

Bracketed figures indicate that their real differences are not statistically significant at 5% level.

110

l

I A comparison of three species of Nasutitennes (Jsoptera: Termitidae) as Termites for Laboratory Bioassays, C.D. Howick and J.W. Creffield.

Gay, F J. and Calaby, J .H. (1970). Termites from the Australian region. In: "Biology of Termites" (K. Krishna and P.M. Weesner, eds), Vol. 2, pp. 393-448. Academic Press, N.Y. and London.

Gay, F J. and Wetherly, A.H. (1958). Laboratory studies of termite resistance. II. The termite resistance of untreated and treated hardboards. CSIRO Aust. Div. Entomol. Tech. Pap. No.3.

Gay, FJ. and Wetherley, A.H. (1971). Laboratory studies of termite resistance. VI. The termite resist­ance of particle boards, fibreboards and plywoods. CSIRO Aust. Div. Entomol. Tech. Pap. No. 11.

Gay, FJ., Greaves, T., Holdaway, F.G. and Wetherly, A.H. (1955). Standard laboratory colonies of

termites for evaluating the resistance of timber, timber preservatives and other materials to termite attack. Bull. Commonw. Scient. Ind. Res. Org. 277' 1-60.

Gay, FJ., Harrow, K.M. and Wetherly, A.H. (1958). Laboratory studies of termite resistance. III. A comparative study of the anti-termitic value of boric acid, zinc chloride and "Tanalith U". CSIRO Aust. Div. Entomol. Tech. Pap. No.4.

Hill, G.F. (1925). Termites from the Australian region: Descriptions of new species and hitherto undescribed castes. Proc. R. Soc. Victoria, 31 (N.S.), Pt II, 206-229.

Hill, G.F. (1942). "Termites (Jsoptera) from the

Table 3

Survival time for 10 g groups of three species of Nasutitennes at two temperatures

Termite species Timber species Temp ('C) Survival time* (days)

N. exitiosus C. apetalum 32 (2 groups died at 77 days)

26 84 + E. regnans 32 84 +

26 84 + Unfed 32 28

26 29

N. graveo/us C. apetalum 32 84 + 26 84 +

E. regnans 32 84 + 26 84 +

Unfed 32 18

26 20

N. walkeri C. apetalum 32 69

26 (2 groups died at 84 days)

E. regnans 32 61

26 67

Unfed 32 18

26 20

• The survival time is the number of days before death of all termites in group (mean of 5 replicates).

Ill

A comparison of three species of Nasutitennes (Isoptera: Termitidae) as Termites for Laboratory Bioassays, C.D. Bowick and J.W. Creffield.

Australian region". Counc. Sci. Ind. Res., Melbourne, Australia.

Bowick, C.D. (1975). Influences of specimen size, test period and matrix on the amounts of wood eaten by similar groups of laboratory termites. Proc. Br. Wood Preserv. Assoc. Ann. Conv. 1975.51-63.

Hawick, C.D. (1978). Influence of crowding during transportation on survival and laboratory feeding of termites (Isoptera). J. Inst. Wood Sci. 8, 28-31.

Hawick, C.D., and Creffield, J.W. (1975). The develop· ment of a standard laboratory bio-assay technique with Mastotennes darwiniensis Froggatt (Isoptera: Mastotermitidae). Z. Angew. Entomol. 18 126-138.

Bowick, C.D. and Creffield, J.W. (1979). A study of intraspecific antagonism in Coptotermes acinaci­fonnis (Froggatt) (Isoptera: Rhinotermitidae). In preparation.

Hawick, C.D., Creffield, J.W. and Lenz, M. (1975). Field collection and laboratory maintenance of Mastotennes dawwiniensis Froggatt (isoptera: Mastotermitidae) for biological assessment studies. J. Aust. Entomol. Soc. 14, 155-160.

Johanson, R. and Hawick, C.D. (1975). Copper· Fluorine-Boron diffusion wood preservative. III Termiticidal effect of fluorine, boron, and F-B complex. Holzforschung, 29,25-29.

Lee, K.E. and Wood, T .G. (1968). Preliminary studies in the role of Nasutitennes exitiosus (Hill) in the cycling of organic matter in a yellow podzolic soil under dry sclerophyll forest in South Australia. Trans. 9th Int. Congr. Soil Sci. 2,11-18.

Lee, K.E. and Wood, T.G. (1971). ''Termites and Soils" Academic Press, London and New York.

Moore, B.P. (1964). Volatile Nasutitennes soldiers (isoptera: Insect Physiol. 10,371-375.

terpenes from Termitidae ). J.

Noirot, C.B. and Noirot-Timothee, C. (1969). The digestive system. In: "Biology of Termites" (K. Krishna and F .M. Weesner, eds), Vol. 1, pp. 49-88. Academic Press, N.Y. and London.

Rudman, P. and Gay, F.J. (1964). The causes of natural durability in timber. XIV. Intra-5pecific variations in termite resistance of cypress pine, Callitris columel­/aris (F. Muell). Holz[orschung, 18, 113-116.

Sutherland, Jean L. (1933). Protozoa from Australian termites. Q. J. Microsc. Sci. 76,145-173.

112

'

Int. Biodeterior. Bull. ISSN 0020-6164 15 {4) I 979. {I 13-118)

SOFT-ROT FUNGI FROM COPPER-CHROME-ARSENIC TREATED HARDWOOD TRANSMISSION POLES

IN TASMANIA M.A. Une 1 and R.H. Cruickshank!

Summary. A survey of CCA treated transmission poles which had developed soft-rot in scattered localities in Tasmania has yielded a variety of Hyphomycetes capable of degrading cellulosic materials. The most frequently occurring actively wood-rotting fungi belonged to the genera Phialophora, Doratomyces and 0/dlodendron. Generally low weight losses of eucalypt and Pbzus woods were recorded for a number of the isolates tested, with the eucalypt woods being more susceptible to attack than Pinus radiata.

Champignons de pourriture moUe isotes de poteaux de trans­missions traitCs au Cuivre-Chromc-Arsenic en Tasmanie. Un examen de poteaux de transmissions traites au CCA et ayant montrC de Ia pourriture moUe dans des sites divers de Tasmanie a per'mis d'isoler une vari€te d'Hyphomycetes capables de dtSgrader les materiaux celtulosiques. Les champignons de pourriture les plus rrequemment rencont!es appartiennent au genre Phialophora, Doratomyces et Oidiodendron. En general, on a note de faibles pertes de massespour les bois d 'Eucalyptus et de Pinus chez un certain nombre d'isolements GtudiC's, !'Eucalyptus Etant plus sensible a l'attaque que le Pinus rad/ata.

Introduction

The widespread incidence of soft-rot in copper· chrome-arsenic (CCA) treated Eucalyptus transmission poles in Australia has become increasingly evident in recent years {Greaves, 1977). This paper describes the nature and characteristics of soft-rot organisms isolated from such poles in Tasmania.

Materials and Methods

Wood sampling To determine the predominant flora associated with

soft-rot in transmission poles, a total of 50 infected poles from separated localities throughout the state were sampled, plus a further 33 poles at a single locality (Wynyard) having a high incidence of soft-rot attr ... k. Samples were taken at, or slightly above, ground line and placed in plastic bags for return to the laboratory.

The predominant species of eucalypt utilized for transmission poles in Tasmania are E. obliqua, E. gigantea, E. lin earls and E. globulus. These timbers were originally impregnated with CCA salts to a retention of approximately 22kg/m3. The poles had been in position for five to nineteen years prior to sampling. Soil pH at 17 of the localities tested ranged from 4 .l to 7 2 with the majority falling within the range 5 .5 - 6.5.

Moderfiiulepilze aus CKA-behandelten Leitungsmasten auf Tasmanien. Eine Ubersicht iiber CKA·behandelte Leitungs­maste, die in vereinzetten Gegenden von Tasmanien von Moderlaule befallen waren, ergab eine Variet'at von Hyphomycetes, die Cellulose-Materialien abbauen konnte. Die am h'aufigsten auftretenden, aktiv holzzerst'tlrenden Pilze gehorten zu den Gattungen Phialophora, Doratomyces und 0/diodendron. Im allgemeinen verursachten die meisten der geprllften lsolierungen geringe Gewichtsverluste an Eucalyptus und Pinus, wobei die Eucalyptus-Holzer antalliger als Pinus radiata waren.

Hongos causantes de ligera podredumbre de pastes electricos tratados con cobre-cromo-arscnico. En diversos localidades de Tasmania, se han desarrollado sabre pastes electricos tratados con CCA variedades de Hyfomycetes capaces de degradar materiales celulosicos. Los bongos productores de podredumbre con mayor actividad pertenecen a los generos Phialophora, Doratomyces y Oidiodendron. Del numero de muestras aisladas y examinadas se registra en general leves perdidas de peso en las maderas de Eucatiptus y Pinos. La madera de Eucaliptus es mas susceptible de ser atacada que Pinus radiata.

Isolation of soft·rot organisms Thin wood shavings {cut with a sterile scalpel blade)

or sawdust samples {Greaves and Savory, I 965) were placed on c~Ilulose agar of the following composition:-

NaN03 KH2P04 MgS04.1H20 Cellulose powder {Whatman CC4l)

Agar Distilled water

pH 5.5

O.Sg l.Og O.Olg

6.0g IS.Og I litre

Plates were incubated at 25°C or 28°C for 2-4 weeks and checked daily for fungal growth. Hypha! tips or spores were streaked onto a medium comprised of:-

Glucose L-asparagine

KH2P04 MgS04.7H20 Yeast extract (Oxoid) Agar Distilled water

IS.Og 2.5g l.Og l.Og O.Sg

IS.Og I litre

Benomyl-malt agar {Ciubbe and Levy, 1977), selective for basidiomycetes, was also used in most cases,

I Dept. of Agricultural Science, The University of Tasmania, GPO Box 252C, HOBART, Tasmania, Australia.

(Received, August 1979).

113

Soft-rot fungi from copper-chrome-arsenic treated power transmission poles in Tasmania, M.A. line and R.H. Cruickshank.

Table 1

Some characteristics of selected fungal isolates from soft-rotted wood samples

Fungal isolate Relative attack on cotton (three weeks) (Note l)

Depth of clearing in cellulose agar deeps (mm) (two weeks) (Note 2)

A. Isolates producing cavity formation in E. obliqua in three weeks.

Ceratocystis sp. I 0

Chaetophoma sp. 4 9

Doratomyces sp. 3 6

Graphium sp. 4 7

Oidiodendron sp. 0 0

Phialophora mutabi/is (3 isolates) 2-4 6-11.5

Pycnostysanus sp. 0

Pyrenochaeta sp. 4 13

B. Other isolates

A ltemaria sp. 4 13

Amblyosporium sp. 4 6

Aposphaeria sp. I 0

Aspergillus sp. 7

Aureobasidium sp. 0 0

Cephalosporiopsis sp. 4 7

Cephalosporium sp. (2 isolates) 1-4 0-6.5

Chrysosporium sp. 4 6

C/adospon"um sp. 2 8

Diplodia sp. 4 0

Epicoccum sp. 3 II

Fusarium sp. 4 10

Glioc/adium sp. 4 8

Helminthosporium sp. 2 7

Mucorsp. 0 0 114

Relative Cx-cellulase activity (Note 3)

Cotton wool (14 days)

0

3

0

I

0

3 (I isolate)

0

3

Eucalyptus sp. delignified wood flour (4 days)

I

n.t.

I

2

0

2-4

0

3

contd ...

Soft-rot fungi from copper-<:hrome-arsenic treated power transmission poles in Tasmania, M.A. line and R.H. Cruickshank.

Table I (continued)

Some characteristics of selected fungal isolates from soft-rotted wood samples

Relative Cx-cellulase activity Depth of (Note 3)

Relative attack clearing in Fungal isolate on cotton cellulose agar Cotton wool Eucalyptus sp.

(three weeks) deeps (mm) (14 days) delignified wood (Note I) (two weeks) flour (4 days)

(Note 2)

B. Other isolates (continued)

Paecilomyces sp. (3 isolates) 0--4 0-7

Penicillium sp. ( 4 isolates) 0-2 0-8

Peyronellaea sp. 2 11

Phoma sp. (2 isolates) 0-3 0-11

Rhizoctonia sp. 2 8

Septonema sp. 0 7

Trichoderma sp. 3 7

Verticillium sp. 2 7

Volutella sp. I 7

*Polystictus versicolor I 10

*Pleurotus lampus I 24

1 Relative attack was determined by measuring the remaining tensile strength of cotton pieces as described in Materials . and Methods.

2 Agar deeps of Rautela and Cowling (1966).

3Carboxy methyl cellulase activity was measured viscometrically as described in Materials and Methods.

*Basidiomycete species

n.t. =not tested.

as well as a medium selective for cellulolytic bacteria (after Cutter and Rosenberg (1971) containing:-

NaN03 05g K2HP04 l.Og Cellulose powder

(Wha tman CC41) Yeast extract MgS04 .7H20 FeS04 .7H20 Nystatin Agar ··•

Distilled water

6.0g O.Sg O.Oig O.Oig O.OSg 8.0g I litre

115

This was autoclaved at 12!°C for IS minutes and poured as an overlay on a sterile base of the same composition but lacking cellulose and solidified with IS .Og/litre of agar.

Assessment of cellulase and wood degrading activity The method of Rautela and Cowling (1966) was

used to test selected fungal isolates for ability to clear phosphoric acid swollen cellulose (\Vhatman COil) and delignified, swollen wood cellulose prepared from hammer-milled wood powder of Eucalyptus sp. The powdered wood was delignified as described by Bailey, Uese and Rosch (1968) and swollen in 8S% phosphoric acid as described by Rautela and Cowling (1966).

' ~ \

Soft-rot fungi from copper-chrome-arsenic treated power transmission poles in Tasmania, M.A. Une and R.H. Cruickshank.

The following medium was used to test the ability of fungal isolates to degrade cotton or sapwood slivers (approximately 2 x 2 x 20 mm) of E. obliqua:-

NaN03 K2HP04 KH2P04 MgS04.7H20 Agar Distilled water

O.Sg O.Sg 2.0g O.Olg

IO.Og 1 litre

2 .Om! aliquots of molten medium were dispensed into bijoux bottles, sealed and autoclaved. Cotton thread (J. & P. Coates so·· and wood slivers were sterilised by autoclaving, placed on the surface of the solidified agar, inoculated, and the bottles capped loosely and incubated at 25°C for three weeks.

Individual threads (three replicates) were then clamped between a fixed support and the hanging end of a length of roller chain. The thread was allowed to support an increasing calibrated weight of chain to the point of thread failure. Relative ability to degrade cotton was recorded on a scale of 0 - 4 in which 0 indicated the strength of sterile cotton threads (1 kg weight supported), and 4 indicated no measurable strength remaining.

Following incubation of wood slivers, surface layers were fixed in 5% gluteraldehyde in O.JM phosphate buffer with evacuation, dehydrated in an alcohol series and embedded in Spurr's low viscosity epoxy resin (Spurr, 1969). Sections (l pm) were cut with an LKB Ultratome using glass knives, then stained with saturated aqueous crystal violet and examined microscopically for fungal attack.

To determine the carboxy methyl cellulase activity of fungal culture filtrates, isolates were grown for two weeks at 28°C in shallow layers of Nilsson's (1974) BVII medium with cotton wool as carbon source and the pH raised to 5.5, and then for four days at 25°C in a medium containing:-

NaN03 K2HP04 MgS04 .7II20 Eucalyptus obliqua

wood flour Distilled water

O.Sg O.Sg O.Oig

4.0g I litre

Samples of culture filtrate (1.0mi) were incubated with I Om! substrate (0 .4% carboxy methyl cellulose in O.JM sodium acetate buffer, pH 5.5) for 30 minl\tes at 45°C prior to assaying using a Wells-Brookfield micro­viscometer. Relative activity was rated on a scale of 0-4.

and Pinus radiata measuring 20mm3 were placed in 190mm glass petri dishes containing a 1 Omm layer of vermiculite saturated with the following (sterile) medium:-

NH4N03 6.0g K2 HP04 l.Og KH2P04 I .25g MgS04 .7H2 0 4.0g Distilled water I litre

(Medium due to Butcher,l975)

Plates were incubated in sealed plastic bags at 22°C for four months.

To test for ability to degrade CCA treated wood, sapwood blocks were treated by vacuum impregnation with CCA solution as described by Hulme and Butcher (1977), giving CCA salt retentions equivaient to 22kg/m 3 for E. globulus and E. ob/iqua, and 30kgfm3 for Pinus radiata.

Results

Characterisation of soft-rot isolates The initial study of 18 soft-rot infected transmission

poles yielded a variety of Hyphomycetes capable of producing degradation of untreated hardwood in a three week period. Selected isolates were identified to generic level and tested for cellulolytic ability. The results are shown in Table l , with a separation of the isolates into two groups depending on their ability to produce cavities in E. obliqua wood slivers in three weeks. Percentage weight losses of sapwood blocks of E. obliqua, E. globulus and Pinus radiata produced by active wood rotting fungi over a 16 week period appear in Table 2. None of these fungal isolates showed significant attack or produced a weight loss of any of the CCA treated wood blocks in 16 weeks.

Fungi producing cavity formation in E. ob/iqua slivers were tested for tolerance to copper sulphate in cellulose agar deeps. Three out of five strains of Phialophora mutabilis showed growth and clearing of the cellulose at a CuS04.SH20 concentration of 2.0%. All other isolates were inhibited at 0.5% CuS04 .51!2 0 concentration.

Predominant soft-rot causing organisms present in CCA treated poles in Tasmania

An indication of the predominant soft-rot fungi associated with the decay of CCA treated poles was provided by a survey of 50 poles showing wood decay from separated localities and of a further 33 poles in a single locality having an apparently high incidence of soft-rot. The following genera were most frequently isolated in the state-wide survey: Penicillium (32/50); Mucor (28/50); Cephalosporium (19/50); Phialophora

Detenninations of weight-loss of wood blocks (14/50); Trichodenna (9/50); Doratomyces (7 /50); A method similar to that of Gersonde and Kerner- Chrysosporium (6/50); Cladosporium (6/50);

Gang {1976) was used but without actual burial of the Alternaria (5/50); and Ceratocystis (5/50), with other blocks. Blocks of sapwood of E. obliqua, E. globulus, fungi being isolated at lower frequencies.

116

I

Soft-rot fungi from copper-chrome-arsenic treated power transmission poles in Tasmania, M.A. line and R.H. Cruickshank.

Table 2 Percentage weight losses of pine and eucalypt sapwood blocks after 16 weeks exposure to various fungal isolates.

Each figure is the average of four replicate blocks. Standard errors are given in brackets

Fungal Species Pinus radiata Eucalyptus obliqua Eucalyptus globulus

Ceratocysris sp. 4.2 (03) 11.4 (2.5) 6.2 (Ll)

Chaetophoma sp. 5.1 (0.2) 3.9 (0.3) 11.9 (2.5)

Graphium sp. 6.5 (0.6) 6.5 (1.4) 7.9 (2.8)

Oidiodendron sp. 7.2 (2.7) 15.9 (3.2) 10.6 (1.9)

Phialophora mutabi/is (a) 4.6 (0.2) 4.9 (0.8) 6.6 (2.2)

Phialophora mutabilis (b) 53 (0.4) 4.8 (0.3) 8.5 (1.3)

.Polystictus versicolor* 5.5 (0.7) 38.4 (10.3) 28.1 (10.1)

The 20mm3 blocks were incubated at 22°C on vermiculite saturated with nutrient medium lacking a source of carbon. * The basidiomycete Polystictus versicolor was not isolated from soft-rotted poles but was included for comparison. No significant weight losses were detected from the CCA treated blocks following fungal exposure.

The study of poles in a single locality (Wynyard) showed a predominance of the following fungal genera: Phialophora (33/33); Oidiodendron (29/33);Penicillium (19/33); Doratomyces (6/33), with various other fungi being isolated at lower frequencies.

Of these frequently occurring fungi isolated from all localities, only isolates identified as Phialophora mutabilis, Doratomyces sp., and Oidiodendron sp. produced cavity formation in E. obliqua wood slivers in a three week period.

No basidiomycete was isolated from soft-rotted samples of any pole tested in the survey. Although cellulolytic bacteria were frequently isolated from wood samples, they were never present in numbers which would indicate that they played a significant role in the wood decay. In fact the low numbers observed suggested surface soil contamination of the wood samples by these bacteria. Included among the bacteria were yellow pigmented Gram negative rods (possibly Cytophaga spp.), Streptomyces spp. and a variety of unidentified isolates.

Discussion From the results of the stiidy undertaken it appears

that soft-rot in CCA treated hardwoods in Tasmania is attributable to members of the hyphomycetes. Of the fungi isolated, only a small proportion were found to form cavities in E. obliqua wood slivers in a three week period, of which Phialophora mutabilis, Doratomyces spp. and Oidiodendron spp. were the most frequently encountered. The Oidiodendron sp. tested, although capable of forming cavities in wood, was inactive in culture on various cellulose substrates. Nilsson (1974) has isolated a wide variety of wood-attacking micro­fungi showing this feature, and has discussed possible reasons for this apparent anomaly.

117

Phialophora mutabilis has previously been associated with soft-rot attack by Henningsson and Nilsson (1976) and Nilsson and Henningsson (1977), who found Phialophora species to be the most common flora isolated from preservative treated woods in Sweden, although the species P. mutabilis was found to be comparatively rare in preservative treated pine and beech posts.

In Australia, actively wood rotting isolates identified as Phialophora richardsiae (Greaves and Savory, 1965) and Phialophora sp. (Greaves, 1972) have been isolated from weathered creosote and CCA treated timbers and Leightley (1978) has found P. richardsiae to be among the dominant soft-rot flora in CCA treated eucalypt transmission poles in Queensland. Other dominant members of the flora reported by Leightley included Paecilomyces varioti, Scytalidium sp. and Alysidium sp.. Paeci/omyces sp. has also been found to be the dominant fungus present in CCA treated E. maculata poles at a burial site in N.S.W. (line, unpublished). However, none of three Paecilomyces sp. isolated from the Tasmanian survey was able to produce cavities in E. obliqua wood in a three week period, though one of these was strongly active in degrading cotton.

Representative isolates of other frequently isolated microfungi (Penicillium spp.; Mucor sp., and Cephalosporium sp.) did not produce cavities in E. obliqua in a three week period, although both Cephalosporium isolates and three out of four Penicillium isolates tested showed cellulase activity on cotton, and in swollen cellulose agar deeps.

A similar pattern was observed for the less frequently occurring fungi although in many instances fungi incapable of forming cavities in E. obliqua over the period tested were isolated from considerable depth in

Soft-rot fungi from copper-chrome-arsenic treated power transmission poles in Tasmania, M.A. llne and R.H. Cruickshank.

the wood_ Most fungi were seen in section to be able to penetrate pit membranes, though many may be slow cavity-formers.

Measurement of the tensile strength of cotton following fungal attack was found to provide a simple and sensitive test for cellulase activity_ In only one instance did an isolate (Septonema sp.) show clearing of cellulose in agar deeps without reducing the tensile strength of cotton, while conversely four isolates showed activity on cotton without producing cellulose hydrolysis in agar deeps. One of these isolates (a Diplodia sp.) produced a strong attack on cotton without affecting the swollen cellulose_

Rather low weight losses of wood blocks were produced by the soft-rot fungi tested in comparison with that from basidiomycete activity. Generally lower weight losses were recorded for untreated Pinus blocks compared with untreated Eucalyptus blocks, which is in agreement with the known high susceptibility of hard­woods to soft-rot attack (Savory, 1954; Nilsson, 1973). The inability of the isolates tested to attack hardwood blocks treated with CCA to the same retention as the original retention in the poles could perhaps indicate leaching of the CCA in the poles over the period prior to sampling.

Acknowledgements

We would like to thank Mr. D. Shaw and other personnel of the Hydro-Electric Commission of Tasmania for the collection of soft-rotted wood samples, and Dr. T. Nilsson, the Swedish University of Agricultural Sciences, Department of Forest Products, Uppsala, Sweden, for identifying isolates of Phialophora mutabilis.

References

Bailey, P.J., Uese, W. and Rosch-, R. (1968). Some aspects of cellulose degradation in lignified cell walls. In: Biodeterioration of Materials. Editors, Walters, A.H., Elphick, JJ., Elsevier, London. 546-557.

Butcher, J.A. (1975). Factors affecting decay of soft­woods by soft-rot fungi. B.W.P.A. Annual Con­vention, 1975. (N.Z. Forest Service Reprint No. 853, ODC 844.2.)

Clubbe, C.P. and Levy, J.F. (1977). Isolation and identification of the fungal flora in treated wood. Revised technique. The International Research Group on Wood Preservation. Document No. IRG/WP/159.

Cutter, J.M. and Rosenberg, F.A. (1971). The role of cellulolytic bacteria in the digestive processes of the shipworm. II. Requirement for bacterial cellulase in the digestive system of teredine borers. In: Bio­deterioration of Materials. Vol. 2, Editors, Walters,

118

A.H., Hueck-van der Plas, E.H. Applied Science, London. 42-51.

Gersonde, M., Kerner-Gang, W. (1976). A review of information available for development of a method for testing wood preservatives with soft-rot fungi. Int. Biodeterior. Bull., 12,5-13.

Greaves, H. (1972). Microbial ecology of untreated and copper-chrome-arsenic treated stakes exposed to a tropical soil. I. The initial invaders. Can. J. Micro­bioi., 18, 1923-1931.

Greaves, H. (1977). Progress towards controlling soft­rot of treated hardwood poles in Australia. The International Research Group on Wood Preservation. Document No. IRG/WP/289.

Greaves, H., Savory, J.G. (1965). Studies of the micro­fungi attacking preservative-treated timber, with particular reference to methods for their isolation. J. Inst. Wood .Sci., 8,45-50.

Henningsson, B., Nilsson, T. (1976). Some aspects on microflora and the decomposition of preservative treated wood in ground contact. Mater. u. Organ. Beiheft, 3,307-318.

Hulme, M.A., Butcher, J .A. (1977). Soft-rot control in hardwoods treated with chromated copper arsenate

preservatives. I. Treatment problems. Mater. u. Organ., 12,81-95.

l.eightley, L.E., (1978). Soft rot fungi found in copper­chrome-arsenic treated hardwood power transmission poles in Queensland. The International Research Group on Wood Preservation, I Oth Annual Meeting, Peebles. Working Group I. Biological Problems.

Nilsson, T. (1973). Studies on wood degradation and cellulolytic activity of microfungi. Studia Forestalia Suecica, 104, 40pp.

Nilsson, T. (1974). The degradation of cellulose and the production of cellulase, xylanase, mannanase, and amylase by wood attacking microfungi. Studia Forestalia Suecica, 114, 61pp.

Nilsson, T., Henningsson, B. (1977). On the occurrence of Phialophora species in preservative treated wood in ground contact. International Research Group on Wood Preservation. Document No. IRG/WP/163.

Rautela, G.S., Cowling, E.B. (1966). Simple cultural test for relative cellulolytic activity of fungi. Appl. Microbial., 14,892-898.

Savory, J .G. (1954). Damage to wood caused by micro­organisms. J. appl. Bact., 17,213-218.

Spurr, A.R. (1969). A low viscosity epoxy resin em­bedding medium for electron microscopy. J. Ultrastruct. Res., 26,31.

i

I I '

1 l

l ~ j

l

1 l '

l

~ il !j I~ '

Int. Biodeterior. Bull. JSSN 0020-6164 15 (4) 1979. (119-123)

A POSSIBLE METHOD FOR ENUMERATING BACTERIA IN WOOD

by JaniceK. Carey1

Summary. A simple technique is described which enables relative numbers of bacteria in a piece of wood to be estimated. Small chips of wood are streaked across petri dishes of a nutrient medium and incubated. The density of colonies developing along the streak varies with the number of bacteria which can be estimated using dilution plates prepared from liquid expressed from replicate material. Manipulation of growth medium or environment could be used to select particular types of organisms.

Methode possible pour compter tes bacteries dans le bois. On d€crit une technique simple permettant d'estimer le nombre relatif de bactEries dans une pi'ece de bois. De petits copeaux de bois sont disposes en raies dans de boites de PC'tri avec milieu nutritif et incubck La densit6' des colonies de dC:veloppant Ie long des raies varie avec le nombre des bactC'ries que l'on peut estimer au moyen de plaques de dilution prepare'es a partir du liquide obtenu avec les·~rCpliques. On pourrait utiliser pour setectionner des types particuliers d 'organismes le milieu de culture ou le milieu environnant.

Introduction

In their review of the association between bacteria and wood, Rossell eta/ (1973) did not include a section on enumeration and there are few papers which make reference to the subject. Greaves (1971) and Shortie and Cowling {1978) comminuted samples of wood under sterile conditions, washed the fragments in sterile water and plated out the _ resulting suspension at various dilutions to give counts of bacterial numbers in liquid expressed from infected material and used dilution plates to obtain pure cultures of the organisms. Dunleavy eta/ (1973) used the dilution plates to provide a count of the bacteria per ml of exudate. Both methods are tedious and time consuming and neither provides a direct count of the bacteria present in the wood sample; they rely on the assumption of a constant relationship between the number of bacteria extracted and a number originally present.

During the course of studies on the colonisation of wood exposed out of,contact with the ground, the need for a rapid but reliable means of estimating the bacterial population became evident. Growth from small sample chips planted on nutrient agar would indicate only the presence of viable bacteria; a few resting spores may not be distinguishable from an active developing population. Preliminary experiments in which chips from air-dried Scots pine (Pinus sy/vestris L.) sapwood blocks were streaked across the surface of the agar before being planted. exhibited no bacterial growth within a three

Ein mOgllches Verfahren zur zihlung von Baktericn in Holz. Es wird ein einfaches Verfahren beschrieben, mit dessen Hilfe relative Zahlen von Bakterien in einem HolzstU.ck geschiitzt werden kOnnen. Kleine Holzspii.ne werden in Petrischalen gelegt, die ein Nlihrmedium enthalten, und werden bebr'Utet. Die Dichte der Kolonien, die sich entlang des Spans entwickeln, variiert je nach der Anzahl der Bakterien, die ermittelt werden, wenn Verdiinnungsplatten verwendet werden, die aus verfllissigtem Vergleichsmaterial hergestellt werden. Eine Manipulation des Wuchsmediums oder der Umweltbedingungen k'Onnte dazu verwendet werden, urn besondere Organismen auszuw3.'w.en.

Un posible metoda para el recuento de bacterias en madera. Se describe una tecnica sencilla que facilita calcular el niimero de bacterias en una pieza de madera. Se toea con virutas de madera sabre el media nutritivo en placas - de petri y se incuban. La densidad de las colonias crecidas en las placas varia con el nUmero de bacterias, el cual puede ser calcutado usando diluciones en placa con liquido optenido de material an~ogo. Variaciones en el media de cultivo o condiciones ambientales pueden ser usadas para seleccionar determinados -tipos de organismos.

day incubation period, either along the streaks or around the chips. In contrast, considerable bacterial growth occurred when samples were taken from similar blocks which, before sampling, had been impregnated with log pond water and incubated for 22 days at room temperature. Levels of bacterial activity between these extremes should give intennediate amounts of growth. The experiments described were attempts to quantify the growth by comparison with results established using the method described by Dunleavy et a/., {1973).

Materials

Scots pine sapwood blocks measuring 50 x 25 x 15 mm were cut from rapidly air-dried stock. Water from the Princes Risborough Laboratory log pond, known to contain an active population of bacteria, was removed on the day of use.

Oxoid nutrient agar (Code CM3) was used for culture plates.

Method

In the first test, eighteen unsterilised test blocks were placed in a beaker, weighted down and covered with water from the log pond. A vacuum of approxi· mately 20 torr was drawn for 10 minutes, then released, thus saturating the blocks. Sets of three replicates were

1 Building Research Establishment, Princes Risborough Laboratory, Princes Risborough, AYLESBURY, Bucks. HP17 9PX.

(Received, August 1979).

119

- , .. -. f :. '" -- - ... l l\ ~-~·..-· ·· h ,. __ .... l ' ' ...... .. : ' 17M&/··· p . \

•• - - . ...._ . ... .

Figure 1. Bacterial growth from three replicate blocks of Scots pine sapwood impregnated with log pond water . Three chips were cut from each block after incubation at

22°C for (left to right) I , 2, 4 , 8 and 12 days (of Table 2).

. . -----

' .

----

A possible method for enumerating bacteria in wood by Janice K. Carey.

Table I

Bacterial counts and growth from sample chips: first test

Incubation 1m pregnant period before Count per ml exudate

sampling (days) Per replicate

1.10 X !03

0 1.00 X 102

2.00 X 102

Deionised water 150 X 103

(Controls) 0 130 X 103

7.00x 102

2.52 X 104

0 9.28 X 104

2.00 X 103

4.16 X 106

3 1.44 X 106

3.20 X 105

8.72 X 106

7 1.77 X 107

1.97 x to7

Log pond water 9 not tested

134 X 106

16 1.75 X 106

3.15x106

2.15xJ06

22 1.92 X 106

3.74x106

t growth affected by the use of moist plates * nutrient agar plates dried before use.

Mean

8.17xl02

4.00 X 104

1.97 X 106

1.54 X 107

not tested

2.08 X 106

2.60 X 106

Growth on nutrient a~ar Along streak Aroun chip

none

none +

confiuentt +

individual* colonies +

almost* + confluent

mostly* individual + colonies

mostly* individual + colonies

Note: Over a period of 11 days, five counts of the bacteria in the log pond water varied between 1.37 x 101 and 1.77 x 103 per ml with a mean value of 6 31 x 102.

121

A possible method for enumerating bacteria in wood by Janice K. Carey.

placed in 800 ml capacity glass jars and covered with pond water; the Jars were closed with ventilated caps and incubated at 22 C for periods of up to 22 days. Control blocks were impregnated with fresh deionised water and sampled immediately.

In the second test, one set of three replicate blocks was impregnated with log pond water and incubated, as above, on each of five occasions. These were time­tabled to give incubation periods of 1, 2, 4, 8 and 12 days by the time at which all the replicates were sampled.

Table 2

Growth from sample chips: second test

Replicate Within blocks block

replicates

Incubation period (days)

1

2

3

1 2 3

1 2 3

I 2 3

I 2

• • 0 • 0 •

• • 0 •• * ••

* •• • •• • ••

4 8 12

*** •• • •• ••• •• ••• ••• *** •••

••• • •• • •• *** • • •• •• ••• • •• •• •• ••• ••• ••• • •• •• *** •••

Growth around the chip occurred with all replicates. Growth along the streak: 0 no growth * few colonies •• •••

more colonies many colonies

Table 3

Tentative correlation of growth from sample chips with estimated numbers of bacteria in the exudate

Growth from sample chips Bacterial count

Growth along Growth around per ml exudate streak chip

0 8.19 X 102

0 + 4.00 X 104

• + 2.00 x 105t •• + 1.97 X 106

*** + 1.54x!07

t estimated value

122

Sampling

Under aseptic conditions, a 12 mm length cut from one end of each block was placed near the top of a small, new polythene bag and squeezed in a small vice. A sample (0 .I ml) of the exudate which collected in the bag was diluted in a 1 in 100 series using sterile deionised water. A I ml sample of each dilution was mixed with approximately 9 ml molten nutrient agar, held at 40°C, and poured into a sterile plastic petri dish. The plates were incubated at 22°C for 3 days, then counted.

The remaining length of each block was split open and small chips approximately IS mm long were cut from the newly exposed face, using a 6 mm wide U­shaped gouge. Each chip was streaked across a plate of nutrient agar and partially embedded in the agar at the end of the streak (Figure I). Three replicate chips could be streaked on each plate. The plates were incubated at 22°C for 3 days. In the second test, only the streak method of assessment was used .

Results

Data from the first test, sampled on different days, are presented in Table I, and data from the second test, sampled on the same day, in Table 2 and Figure I. A tentative correlation between the two methods of test is presented in Table 3.

Discussion

In the first test, the bacterial counts obtained by the method of Dunleavy et a/ (1973) showed good replication. The counts increased over the first seven days of incubation; lower counts were recorded after 16 and 22 days suggesting a decline in the population by these times. These results were paralleled by the growth from the sample chips. Those from blocks impregnated with deionised water produced no growth, whilst those from blocks impregnated with log pond water but sampled without prior incubation produced some growth around the chip. Chips from blocks impregnated with pond water and incubated for 3 days produced almost confluent growth along the streak due to the free moisture on the surface of the plates; for subsequent series plates were dried at 45°C for a few hours before use to remove this moisture. Most colonies were produced by chips from blocks incubated for 9 days before sampling; there were fewer colonies after 16 and 22 days incubation.

Estimation of the relative numbers of colonies along the streak was hampered because only sequential obser­vations were possible. Therefore, in the second test replicate sets of blocks were impregnated with pond water in sequence, and sampled and observed simultaneously (Table 2). The water was freshly drawn from the log pond on each occasion to minimise variation in the bacterial population. A rather crude subjective scale was developed to assess the results

A possible method for enumerating bacteria in wood by Janice K. Carey.

which can be compared with the photographic record (Figure I). Improvement in accuracy of the assessment may be possible, for example by counting the number of cokonies per cm2.

A degree of similarity was observed between the subjective estimates of the bacterial growth from chips taken from blocks incubated for similar periods in the two tests. A tentative correlation can therefore be suggested between the counts made in the first test and the similar growth observations in both tests (Table 3). The absence of growth in the streak technique is not an inaccuracy because any background count from control material (8 .19 x 102 bacteria per m1 of exudate in this case) would normally be discounted. Impregnating with log pond water, which resulted in a significant increase in the number of bacteria in the exudate, also gave visible growth around the chip; such growth would, therefore, indicate some proliferation of bacteria. Along the streak a growth rating of *** was correlated with counts in excess of 1.54 x 107 per m1 of exudate. This figure is similar to the maximum counts obtained by Dunleavy et a/ (1973) from water .. tored spruce but low compared to counts normally obtained in nutrient­rich liquid cultures of bacteria. The present method is therefore expected to be sensitive to the range of bacterial numbers likely to be found in timber exposed out of contact with the ground.

The technique should be capable of broad application to a range of experimental or practical situations, though the correlation between the density of colonies· along the streak and the numbers of bacteria in the wood exudate may need to be established for each new use. Additionally, enumeration of selected groups of bacteria should be possible by use of selective media or the manipulation of temperature or available oxygen during incubation.

Acknowledgement

This work was carried out during postgraduate studies at Imperial College, London.

References

Dunleavy, J.A., Maroney, J.P. and Rossell, S.E. (1973). The association of bacteria with the increased per· meability of water-stored spruce wood. Rec. ann. Conv. Br. Wood Preserv. Ass. 1973, 127-148.

Greaves, H. (1971). Biodeterioration of tropical hard· woad chips in outdoor storage. TAPPJ. 54, (7) 1128-1132.

Knuth, D.T. and McCoy, E. (1962). Bacterial deterior· ation of pine logs in pond storage. Forest Prod. J. 12, (9) 437-442.

Rossell, S.E., Abbot, E.GM. and levy, J.F. (1973). Bacteria and wood (A review of the literature relating to the presence, action and interaction of bacteria in

123

wood). J. Jnst. Wood Sci. 6, (2), 28-35.

Shortie, W.C. and Cowling, E.B. (1978).1 Development of discoloration, decay and micro-organisms follow· ing wounding of sweet gum and yellow-popular trees. Phytopathology. 68, (4) 609-616.

SPECIALISED

Prepared and published by the Biodeterioration Centre University of ASTON

Specialised bibliographies are produced from the Biodeterioration Information Centre's document collection from 1965 as listed in the bibliographic journals Biodeterioration Research Titles (B.R.T.) and Waste Materials Biodeterioration (W.M.B.).

Bibliographies may be updated by use of B.R.T. and W.M.B. or purchase of new editions of existing titles. Copies of papers listed may be purchased from the Biodeterioration Information Centre.

Following are Bibliographies currently available- all currently updated

SB1 Glass, Ceramics and Optical Equipment- 28 references £4.50

SB2 Stone, Brick and Concrete - 85 references £6.00

SB3 Microbial Corrosion of Metals - 250 references £8.50

SB4 Micro-organisms in Metal Extraction - 100 references £6.00

SB5 Marine Fouling- 475 references £12.00

SB6 Fouling of Pipelines and Water Systems - 145 references £6.50

SB7 Aquatic Weeds and Fouling of Waterways -150 references £7.00

SBB Rubber and Plastics Biodeterioration- 235 references £8.00

SB9 Fuels, Hydrocarbons and Lubricants in Biodeterioration -425 references £10.00

SB10 Pharmaceutical Products and Cosmetics- 180 references £7.00

SB11 Termites- behaviour and control -350 references £10.00

SB12 Com posting of Agricultural and Municipal Wastes - 130 references £7.00

SB15 Paints - 360 references £10.00

SB16 Works of Art and Museum Specimens - 70 references £6.00

SB17 Rodents - 570 references £14.00

SB18 Single-cell Protein from Wastes- 294 references £9.00

SB21 Pulp and Paper- 252 references £9.00

SB22 Algae as Deteriogens- 186 references £7.00

Orders for published Specialised Bibliographies or requests for the preparation of Specialised Bibliographies

in other subjects should be addressed to:

Dr. D. Allsopp, Biodeterioration Centre, The University of Aston, St. Peter's College, College Road, Birmingham B8 3TE. England.

Int. Biodeterior. Bull (ISSN 0020-6164) 15 (4) 1979. (125-132)

THE USE OF PITTING POTENTIAL TO STUDY THE MICROBIAL CORROSION OF 2024 ALUMINIUM ALLOY

R.C. Salvarezza, A.F .L. de Mele and H.A. Videla 1

Summary. Several isolates obtained from fuel storage tank sludges were used in order to extend and confum previous information on the influence of different microorganisms on the corrosion process of aluminium and some alloys in fuel­water systems. The strains used were:- Cladosporium resinae, Candida sp. and two strains of Pseudomonas aernginosa.

Due to its susceptibility to microbial attack, 2024 alloy was employed. The influence of each biological species on the pitting potential (Ep) of the alloy was studied using two different methods of Ep evaluation. In order to establish the relation between Ep decrease and metal damage, ionic aluminium concentration and weight loss of test pieces were compared with Ep variation.

The results confirm that Ep could adequately serve to follow the electrochemical behaviour of aluminium and its alloys and also to determine the importance of each biological species in respect of the degree of attack of aluminium and its alloys.

L'utilization de le potentiel de rupture pour etudier Ia corrosion microbiologique de l'alliage de l'aluminium 2024. Avec le propos d 'amplier et de confmner une information antCrieure sur !'influence des certains microorganismes dans le processus de corrosion de !'aluminium et de ses alliages dans syst~mes eau­carburant nous avons utiliSe divers isoiCs provenant des se'diments obtenu des reservoirs de carburants des avions 3. reaction. Trois diflerentes espCces ant Ct6 utilise: Cladosporium resinae, Candida sp et deux souches de Pseudomonas aeruginosa.

L 'alliage 2024 a eit6 employe tenant compte 3. sa suceptibilite '3 l'agression microbienne. Avec le propos d'Ctudierrinflu(mce de chaque esp"ece biologique sur le potentiel de rupture de l'alliage on a utilis€ deux m6thodes de mesure du potentiel de rupture. Les valeurs de l'aluminium ionique et Ia perte de poids des €chantillons ant €te comparE avec 1a variation de rupture pour ainsi trouver Ia relation entre la diminution de ce paten tiel et l'endommagement du metal.

Notres resultates indiquent que le potentiel de rupture peut 'S'tre employe pour suivre la conduite etectrochimique de l'aluminium et ces alliages comme a Cte etablie d'abo_rd et aussi pour determiner l'importance de chaque esp'ece biologique dans le grade de l'ataque de metal.

Introduction

As a direct consquence of the increasing use of jet fuel (kerosene fraction) serious failures in aluminium components of aircraft structures have been reported during the last two decades (Ward, 1963; Churchill, 1963).

Several authors have noted the microbiological nature of jet fuel storage sludge as well as the ability

Die Bestimmung des Lochfransspotential als Methode zu unter­suchung der Mikrobiologische Korrosion der Aluminiumlegicr­ung 2024. Es wurden verschiedene St:Unme aus R\ickstinden von Dllsentreibstofftanken benuzt urn fri.ihere Resultate Uber die Wirkung verschiedener Mikroorganismen auf die Korrosions· prozesse des Aluminiums und der Aluminiumlegierungen in Waser-Dusentreibstoffsystemen erweitem und besiatigen zu konnen. Die betr.vier starnme waren: Cladosporium resinae, Candida sp. und zwei Stamme von Pseudomonas aeruginosa.

Wegen seiner Empfmdlichkeit gegeniiber einem milcro­biologischen Angriff wurde die Aluminium legierung 2024 angewahlt. Es wurden zwei verschiedene Methoden zur Messung des Lochfrasspotentials angewandt urn den Einfluss jeder biologischen Spezie auf das Lochfrasspotential der Legierung untersuchen zu k'Onnen. Urn den Zusammenhang zwischen lochfrasspotentialminderung und Metallschaden ermitteln zu k'Onnen, worden an Aluminium Proben die Aluminium ionen· konzentration und der Gewichtsverlust mit der Lochfrass­potentia.laD.derung verglichen.

Unsere Ergebnise deuten darauf hin dass das Mass des Loch­frasspotentials benutzt werden kann, urn das elektrochemische Verhalten von Aluminium und Aluminium legierungen und d.amit den Einfluss jeder Spezie auf den Schadengrad des Metalls zu untersuchen.

Uso del potencial de picado para estudiar la corrosion micro­biologica de Ia aleacion de alumino 2024. Con el propOsito de extender y confmnar informaciOn previa sabre Ia influencia de diferentes microorganismos en el proceso de corrosiOn del aluminio y aleaciones en sistemas agua combustible se utilizaron varies aislados provenientes de tanques de almacenaje. Las cuatro cepas utilizadas fueron: Cladosporium resinae, Candida spy dos cepas de Pseudomonas aeruginosa.

Se empleO 1a aleaci6n 2024 debido a su suceptibilidad al ataque. Se estudi5 Ia influencia de cada cspecie en el potencial de picado (Ep) de 1a aleaciOn, utilizando dos methodes de evaluacion del Ep. Para-. establecer le relaciOn entre Ia disminuci6n del Ep y el diln.o del metal, se compararon Ia concentraciOn de aluminio iOnico y Ia perdida de peso de las probetas con Ia variaciOn del Ep.

Nuestros resultados sugieren que el Ep puede servir adecuadamente para seguir el comportamiento electroqufmico del aluminio y aleaciones como fue establecido previamente y permite ademis determinar 1a importancia de cada especie con respecto al grade de ataque sabre aleaciones de aluminio.

of different species of bacteria, yeasts and fungi, to metabolize kerosene fraction c8 - c18 (Bakanauskas, 1958; Churchill and I.eathen, 1961; Darby, Simmons and Wiley, 1968).

However, there is disagreement as to the participation of biological agents in the corrosion process (Stormont 1961; London, Finefrock and Killian, 1965). Parbery (1968); Hedrick (1970) and Hendey (1964) demonstrated the importance of the role played by

1Jnstituto de Investigaciones Fisicoquimicas Teoricas y Aplicases, Seccion Bioelectroquimica. Surcursal 4, Casilla de Correa 16, 1900 LA PLATA, Argentinia.

(Received August 1979).

125

The use of pitting potential to study the microbial corrosion of 2024 aluminium alloy, R.C. Salvarezza, A.F.L. de Mele and H.A. Videla.

certain species of microorganisms in the attack of aluminium alloys.

From the numerous biological contaminants of jet fuel capable of surviving in fuel-water systems, Pseudomonas aerngitzosa among bacteria and Cladosporium resinae among fungi have been considered as the most active species concerned with corrosion on aluminium and its alloys (Parbery, 1971 a; Hedrick, Miller, Halkias and Hildebrand, 1964).

In a previous study (Mele, Salvarezza and Videla, 1979) we made a preliminary evaluation of the influence of these contaminants of jet fuel on the pitting potential (Ep) of aluminium and two alloys used in the aircraft industry. The pitting potential of a metal in a potentia­static polarization curve is the potential below which the metal surface remains passive and above which pitting nucleates on the metal surface. Increase of the concentration of an aggressive substance in a medium produces a decrease in Ep. 'This parameter, Ep, is particularly useful in the case of microbial corrosion of aluminium alloys because of their susceptibility to localized corrosion.

The present study was undertaken to investigate the relationship between Ep variation and the degree of metal damage produced by four strains of contamin­ants with the purpose of evaluating the aggressivity of each species against 2024 alloy.

Experimental

Four different strains of microorganisms isolated from fuel storage tanks were used: Cladosporium resinae, Candida sp, and two strains of Pseudomonas aernginosa (Ps. aernginosa I and Ps. aernginosa II) Ps. aemginosa I is the same strain as that used in a previous study which was characterized by low acid production (Mele, Salvarezza and Videla, 1979). Ps. aeruginosa II is a new isolate capable of producing an evident decrease in the medium pH. The composition of the medium used was:

CaC1 2 MgS04 (NH4)zS04

1.8 x 10-4M 1.7 X 10-3M 7.6 X 10- 3M

dissolved in deionized water. The initial pH of the medium was adjusted to 7.00 by addition of NaOH 0 .IN. The medium was sterilized by autoclaving but the ammonium sulphate was added as a solution (sterilized by filtration) after autoclaving.

Phosphorus was omitted from this medium because it has been conclusively demonstrated that weak acids act as inhibitors of the pitting process and modify the type of film formed on the metal surface (Galvele, 1977). Phosphorus (as phosphate anion) would, by its buffering action, have prevented localized acidification which is necessary to the pitting process. Good growth was obtained which suggests that the phosphorus requirement of the organisms was supplied by the fuel itself.

126

Fungus, bacteria,and yeast were grown in erlenmeyer flasks of 500 mi. The fuel/medium ratio was 1/1 (I 00 ml of sterile medium of 100 mi of JPI as the carbon source) for the fungus, and 4/1 (200 mi of sterile medium and SO m1 of JPI) for the bacteria and yeast. JPI was sterilized by filtration through gelman membrane of 02 }' pore size. Static conditions were used for C. resinae growth. In the case of Ps. aernginosa I, Ps. aernginosa II and Candida sp. cultures were agitated during the first 24 hours to provide an adequate oxygen supply, and thereafter static conditions were used. The temperature was maintained at 28°C. To estimate bacteria and yeast growth the viable count method was employed. In the case of C. resinae both pH and the dry weight of mycelium were used (Parbery 1971 b). The dry weight measurement was performed by drying the filtered mycelium to constant weight, a whole culture being sacrificed for each of these measure­ments.

The composition of the 2024 alloy is: Cu 3 .80% by weight Mg 1.53% by weight Zn 0.09% by weight Si 0 .I 5% by weight Fe 032% by weight AI to 100%

Test pieces were chemically polished.

The electrochemical measurement was performed in a pyrex glass cell maintained at 28°C. The counter electrode was a platinum wire and the potential was referred to a saturated calomel electrode (SCE) through a Luggin capillary. In order to study the electro­chemical behaviour of 2024 alloy the experimental measurements were made in the following way:­Starting from the rest potential, anodic and cathodic polarization curves were obtained changing the potential by steps of 10 mY/minute in the anodic and cathodic direction respectively.

In the case of the anodic curves, the medium was first deaerated with pure nitrogen. The Ep values derived from these curves were confirmed by means of current/time experiments performed at a constant potential in the vicinity of Ep. The potentials were changed in steps of 10 mV/30 minutes. Each determination (Ep, pH and microorganism number), was made on a different culture, in stationary phase of growth. ·

The degree of damage to the test pieces was followed by two different methods: I . the loss of weight of the test pieces; 2. measurement of the amount of ionic aluminium in the medium, evaluated by means of a colourimetric technique ('aluminon method'), (Vogel, 1953), using 2 ml samples removed from the flasks. Subsequently corrections were made for the consequent changes in volume. The test pieces were circular of 16 mm diameter (4 cm2 surface area). They were suspended in the medium fixed to a glass rod using a hole drilled near the edge of each specimen.

The use of pitting potential to study the microbial corrosion of 2024 aluminium alloy, R.C. Salvarezza, A.F.L. de. Mele and H.A. Videla.

After ionic aluminium and loss of weight measure· ments had been made a sample of each culture was inoculated into specific media to verify the viability of the microorganisms. For loss of weight measurements the test pieces were cleaned mechanically to remove the non-adherent white deposit which formed and then dried overnight at 30°C.

The electrochemical measurements in contaminated media as well as the ionic aluminium and loss of weight determinations were always performed after the cultures had reached the stationary phase of growth.

Results

Anodic potentiostatic polarization curves for 2024 alloy in sterile medium and different contaminated media are shown in figure I. These curves show a passive range where no attack was observed, but as the potential was increased to the Ep an evident increase in the current density was found and pitting started on the metal surface. The Ep values derived from polarization curves were confirmed by using current /time plots. Similar results were obtained by means of both techniques. In Figure 2 a current/time plot for 2024 alloy in contaminated medium by Ps. aeruginosa II is shown. No appreciable variation in the current wtth the time was found in the passive range of potentials, but when Ep was reached a marked increase in the current could be seen. Samples were taken at potentials both below and above the pitting potential and the medium was analyzed for ionic aluminium. Ionic aluminium could only be detected when the potential was more anodic than Ep. Cathodic potentiostatic polarization curves were performed in the aqueous phase of cultures that had reached the stationary phase of

NE u -<(

> .... (JJ

1< -0.42v

• -0.43v

+ -0.44v

• -0.45v

• -0.53v

growth in order to study the influence of micro· organisms on the cathodic rate. No appreciable effect on the cathodic current density with respect to sterile medium could be observed for the different micro· organisms as shown in figure 3.

The degree of attack as a function of time, asshown by colourirnetric ionic aluminium estimation can be seen in figure 4. No increase in ionic aluminium concentration was found in sterile medium. In the cases of C. resinae, Candida sp. and both strains of Ps. aeruginosa higher levels of ionic aluminium with respect

w u w

-0,30

; -0,40

; -0,50

w ~

0

a. -0,60

10 ...

C U R R E N T DENS I TV 2

Atcm

Figure I. Typical anodic polarizarion curves for 2024 alloy in de·aerated media. Potential in volts referred to a saturated calomel electrode (SCE). The point at which each curve changes suddenly in form is the pitting potential, Ep.

z w -·---------· ..... -------·------ ~-. - •-- II --~

c .... 1rP z w a: a: ::J

u

- -·-X'

..x' /'

-/

, -

~ -· .;.:-:::.;.: :.-- ·---_-_-_::_-_:~,f.:.:.:::::: .::1-:.-_-_-_:.:.:.: ..:"'---_ .:: _-_ ::----·.;.: _-_ -_:.: :::~ ·-=··-·-- =-t- ----- -- _ .. _ -- --- --- ·---- -- ----·- --------·-- - ---- --4

·--··--- ·- -- - - - ---·- - - - - - - -·- - - - -- - ... - - - - - - - ... - - - - - -. ' ' '

0 1 2 3 5 10 20 30 TIME(MIN)

Figure 2. Potentiostatic current/time curves recorded for 2024 alloy at various potentials in de·aerated Pseudomonas aeruginosa II culture.

127

The use of pitting potential to study the microbial corrosion of 2024 aluminium alloy, R.C. Salvarezza, A.F.L. de Mele and H.A. Videla.

to sterile medium could be observed, but the greatest concentration was obtained in the presence of C. resinae. In table I are shown the loss of weight of several 2024 test pieces in contact with the different microorganisms studied. In agreement with the measurements of ionic aluminium concentrations, greatest weight losses were obtained for the test pieces immersed in C. resinae comtaminated medium, while the lowest values were found for the sterile medium. Intermediate values were measured for Ps. aeruginosa I Ps. aeruginosa II and Candida sp. After 10 days of exposure to C. resinae, Ps. aeruginosa I and Ps. aeruginosa II culture media, the aspect of the three test pieces assayed can be seen in figure 5 (a, b and c respectively). A test piece immersed for the same period in sterile medium (5 d) has also been included for comparison.

Loss of weight of aluminium 99 99 test pieces in different contaminated media are also shown in table I. It will be seen that the alloy suffers greater weight loss than the aluminium 99.99 thus confirming the greater susceptibility of the alloy to corrosion. Table 2 shows the relationship between Ep, growth of microorganisms and pH. The lower values of Ep and pH correspond to C. resinae. Similar values of Ep were obtained for bacteria and yeast (slightly lower than that corresponding to sterile medium) in the range 5-7 pH.

Discussion

There is general agreement in the literature on the important role of C. resinae in the corrosion process of aluminium and its alloys in fuel/water systems (Parbery, 1971 a; Hedrick, 1970). In contrast the role of aerobic bacteria in the process has not yet been clarified. Among those bacteria Ps. aeruginosa is the most frequently found. Blanchard and Gaucher (1967) attribute an active participation in the aluminium attack through consumption by Ps. aeruginosa of corrosion inhibitors present in the medium. Aa an alternative these authors suggest the production of corrosive organic compounds of large molecular weight which they studied by Sephadex chromatography. Hedrik et a/., (1967) attribute to Ps. aeruginosa the capacity of producing corrosion especially on high percentage magnesium alloys such as 7075 and 2924. Parbery (1971 a) suggests that these bacteria are able to cause corrosion although C. resinae plays the principal role due to its better adaptability to the medium.

In a previous analysis of the anodic behaviour of aluminium and two alloys through potentiostatic polarization curves, we have found an Ep decrease in media contaminated with C. resinae compared to sterile medium. A small decrease of this parameter was observed in the case of Ps. aeruginosa culture for 2024 alloy (Mele, Salvarezza and Videla, 1979).

similar behaviour characterized by a small decrease of the Ep in comparison with sterile medium.

According to recent work on pitting corrosion of aluminium alloys in natural waters (Nilsen and Bardal, 1977) the corrosion rate is highly cathodically controlled. The capacity of sulphate reducing bacteria to produce cathodic depolarization has been extensively studied in the corrosion of iron and steel (Booth and Tiller, 1960; Costello, 1974 ). Similar activity has been attributed to these bacteria in the case of aluminium (Iverson, 1967; Tiller and Booth, 1968).

w (J -060 !!!. ' "-~ .. .... -070 z ' w ... 0

n. -qso

• + • • 0 +. ·.··.:

Ps. aeruginoSll

-5 10

C. resirure

CURRENT DENSITY Alcm2

Figure 3. Cathodic polarization curves for 2024 alloy in different media.

asr-----------------------------,

30 0

N~ 25 0

" " ~

:;; ::>

2

:;; ::> ~ .. " 2

0

20

15 -

10

0

•r- • • . ..

0- C. resinae

Ps. aerugino!ll

Candida sp.

......... .. rr--• • , ____

+

• \

Sterile medium

+

•

.., 7 0~----L---~~--~----~-----J

0 2 4 6 8 10 The results obtained in the present work using this

alloy, characterized by its higher susceptibility to TIME ld ays}

corrosion in fuel/water systems (McKenzie, Akbar and Miller, 1977), confirm our previous observations. Both Figure 4. Change in ionic aluminium with time for strains of Ps. aeruginosa studied and Candida sp. show a 2024 alloy in different media.

128

The use of pitting potential to study the microbial corrosion of 2024 aluminium alloy, R.C. Salvarezza, A.F.L. de Mele and I LA. Videla.

In an attempt to establish whether the species used in the present work could have any influence on the cathodic process, we have made cathodic potentiostatic polarization curves employing the cultures used in the anodic experiments . No significant influence on the rate of the cathodic process could be observed in the potential range studied. With regard to the lack of any differentiating effect in the cathodic reaction for the cultures used, it is eviden t that the pitting potential (obtained thro ugh the anodic polarization curves) becomes of great importance in the study of any difference in the behaviour of the species in the corrosion process.

Considering the electrochemical nature of corrosion the whole process depends on the cathodic and the anodic reaction which determine the value of the corrosion potential of the metal. If the value of this potential remains below the pitting potential (more cathodic) neither pitting nor ionic aluminium could be detected . On the o ther hand , when corrosion potential is higher than the Ep , ionic aluminium and pitting could be determined.

a

c

Table I

Loss in weight of 2024 alloy and aluminium 99.99 in contact with different microorganisms for 9 days

Microorganism

Pseudomonas aemginosa I

Pseudomonas aeruginosa II

Candida sp.

Cladosporium resinae

Sterile medium

b

d

2024

30.0

32.0

25 .0

285 .0

0 .0

Loss in weight mg/dm2

Al 99.99

4.0

12.5

2.5

45.0

0.0

Figure 5 . 2024 alloy test pieces exposed to media containing different microorganisms for 10 days.

a. Cladosporium resinae b. Pseudomonas aemginosa 1 c. Pseudomonas aentginosa II d. Sterile medium

n1e test pieces are 16 mm in di:1meter and have a total surface area of 4 cm2

129

The use of pitting potential to study the microbial corrosion of 2024 aluminium alloy, R.C. Salvarezza, A.F.L. de Mele and H.A. Videla.

Table 2

Pitting potential (Ep ), numbers of organisms, and pH.

Microorganisms Ep Microorganism number x I oSfmJ mV,SCE* pH

Pseudomonas aeruginosa I 30 -350 7.2 .. 10 -410 6.7 .. .. 21 -380 6.4 .. 42 -390 6.9

Pseudomonas aeruginosa II 20 -410 4.9 .. .. 32 -430 5.0 .. 50 -390 5.2 .. 13 -430 4.9

Candida sp. 12 -390 5.8 .. .. 5 -430 6.2

.. .. -390 6.9

Dry wt. jf:Y~elium per as

Cladosporium resinae 20mg -480 4.2 .. not measured -500 5.0 .. .. not measured -510 4.0 .. lSOmg -530 2.9 ..

not measured -510 3.2 .. .. 8mg -440 5.2

Sterile medium nil -350 7.0

nil -370 7.0

• Millivolts vs. saturated calomel electrode

130

The use of pitting potential to study the microbial corrosion of 2024 aluminium alloy, R.C. Salvarezza, A.F.L. de Mele and H.A. Videla.

The measurement of the ionic aluminium levels coming from the dissolution of test pieces immersed in the contaminated media shows an increase with time. Simultaneously pits could be detected through surface observation. In the case of sterile medium, ionic aluminium levels are low and constant (fig. 4) and no pitting could be seen on the metal surface. The magnitude of the metal damage is appreciably higher for test pieces immersed in C. resinae cultures as can be seen in figure 5.

In several studies of corrosion of aluminium and its alloys in fuel/water systems weight change techniques have been used to evaluate the metal damage (Hendey, 1964; Parbery, 1968; Hedrick, Reynolds and Crum, 1967). Due to the susceptibility of aluminium to localized corrosion the degree of damage to the metal does not always have a direct relation to the levels of dissolved metal. Notwithstanding this, measurement of weight change simultaneously with data obtained by means of ionic aluminium measurement and visual observation of the test pieces have enabled us to arrive at a greater understanding of the problem.

If a comparison is made between ionic aluminium levels and weight loss measurements a difference can be found. 1his difference could be attributed to the formation of insoluble corrosion products on the metai surface. 1his fact is supported by the production of a white deposit on all the test pieces used, which can be attributed to J>-aluminium hydroxide (Guillaume, Croissant, Grimadeau, Valensi and Brison, 1973; Hedrick, Reynolds and Crum, 1967).

From analysis of all these data it can be deduced that the capacity to produce corrosion is markedly lower for Ps. aernginosa and other frequent contaminants (e.g. Candida sp) than that of C. resinae.

Nevertheless, Guillaume, Grimadeau and Brisou, (1977) have shown that the aggressivity of these micro­organisms can be appreciably higher when death of the cells occurs. In this case, the complexing substances capable of causing corrosion increase remarkably due to cellular lysis. These workers demonstrated this using nickel, zinc, copper and aluminium in different enriched media.

In conclusion, considering the similar cathodic behaviour of the alloy in the presence of the different

· microorganisms, we hereby emphasise the usefulness of the pitting potential to evaluate the action of the different biological contaminants of fuel/water systems on the corrosion of aluminium and its alloys.

Acknowledgements

The authors are grateful to the Department of Micro­bioloby and Immunology of the Faculty of Pharmacy and Biochemistry of the University of Buenos Aires for the assistance in the identification of the strains used in this work.

131

References

Bakanauskas, S. (1958). Bacterial activity in JP 4 fuel. U.S. Air Force, Wright Air Develop. Center. Tech. Rept.. 58-32.

Blanchard, G.C., Goucher, C.R. (1967). Aluminium corrosion processes in microbial cultures. Electro­chem. Techno/. 5, 79-83.

Booth, G.H. and Tiller, AK. (1960). Polarization studies of mild steel in cultures of sulphate reducing bacteria. Trans. Faraday Soc. 56 1689-1696.

Churchill, A.V. (1963). Microbial fuel tank corrosion mechanisms and contributing factors. Mater. Protec. 2 19-23.

Churchill, A.V. and Leathen, W.N. (1961). Develop­ment of microbial sludge inhibitors. U.S. Air Force ASP Tech. Rept. 61-193.

Costello, J .A. (1974). Cathodic deplorization by sulphate reducing bacteria. South African Journal o[Science 70,202-205.

Darby, R.T., Simmons, E.G. and Wiley, B. (1968). A survey of fungi in a military aircraft fuel supply system. Int. Biodeterior. Bull. 4, (I) 39-41.

Galvele, J.R. (1977). Present state of understanding of the breakdown of passivity and repassivation. 4th International Symposium on passivity. Airlie, Virginia, U.S.A.

Fouroulis, Z.A. and Thubrikar. (1976). On the corres­pondence between critical pitting potential and pitting of aluminium under conditions of natural immersion. Electrochem. Acta. 21 225-230.

Guillaume, 1., Croissant, M., Grimadeau, J., Valensi, G. and Brisou, J. (1973). Conditions d'immunit~ et de corrosion de l 'aluminium dans un milieu bacteriCn doux et marin. Co"os. Sci. 14 321.

Guillaume, I., Grimadeau, J., and Brisou, J. (1977). Contribution bacteriCnne a Ia corrosion et la protection des metaux. Co"os. Sci. 17. 753-763..,_

Hedrick, li.G. (1970). Microbial corrosion of aluminium Mater. Protec. 9, 27-31.

Hedrick, H.G., Miller, C.E., Halkias, J .E. and Hildebrand, J.F. (1964). Selection of a microbial corrosion system for studying effects on structural aluminium alloys. Appl. Microbial. 12 (3) 197-200.

Hedrick, H.G., Reynolds, RJ. and Crum, M.G. (1967). Factors influencing the mechanism of corrosion of aluminium alloys by aerobic bacteria. Develop. Ind. Microbial. 8, 267-274.

Hendey, N.J. (1964). Some observations on aados­porium resinae as a fuel contaminant and its possible

The use of pitting potential to study the microbial corrosion of 2024 aluminium alloy, R.C. Salvarezza, A.F.L. de Mele and H.A. Videla.

role in the corrosion of aluminium alloy fuel tanks. Trans. Brit. Mycol. Soc. 47 (4) 467-4 75.

Iverson, W.P. (1967). A possible role for sulphate reducers in the corrosion of aluminium alloys. Electrochem. Techno/. 5 (3-4) 77-79.

London, S.A., Finefrock, V.H. and Kiillan, L.N. (1965). Microbial activity in Air Force jet fuel systems. Develop.Ind.Microbiol. 6,61-91.

McKenzie, P., Akbar, A.S. and Miller, J.D. (1977). Microbial corrosion affecting the petroleum industry. Institute of Petroleum (Technical Paper) 37-50.

Mele, F.L. de, Salvarezza, R.C. and Videla, H.A. (1979). Microbial contaminants influencing the electro­chemical behaviour of aluminium and its alloys in fuel/water systems. Int. Biodeterior. Bull. IS (2) 39-44.

Muller, E. (1974). Efecto de los aleantes sobre el potencial de picado de aluminio. Thesis, University of Rosario, Argentina.

Nilsen, N. and Bardal, E. (1977). Short duration tests and new criteria for characterization of pitting resistance of aluminium alloys. Corros. Sci. 17, 635-646.

Parbery, D.G. (I 968). The role of Cladosporium resinae in the corrosion of aluminium alloys. Int. Biodeterior Bull. 4, 79-81.

Parbery, D.G. (1971a). Biological problems in jet aviation,·, fuel and the biology of Amorphotheca resinae. Mater. u. Organismen. 6, 161-288.

Parbery, D.G. (i971b). Physical factors influencing growth of Amorphotheca resinae in culture. Int. Biodeterior. Bull. 7 (I) 5-9.

Salvarezza, R.C. and Videla, H.A. (1978). Corrosion of aluminium and its alloys by microbial contamin· ants of jet fuels. Extended abstracts from 7th. Inter­national Congress on Metallic Corrosion. Rio de Janiero, Brasil. 293-295.

Stormont, D.H. (1961). Do jet fuel bacteria cause slime corrosion? Oil and Gas Journal 59 82-84.

Tiller, A.K. and Booth, G.H. (1968). Anaerobic corros· ion of aluminium by sulphate reducing bacteria. Corrosion Sci. 8 549-555.

Vogel, A. (1953). Quantitative Inorganic Analysis, Theory and Practice. I..ongmans Green & Co. LONDON. p.652.

Ward, C.B. (1963). Corrosion resulting from fuel tank contamination. Mater. Protec. 2, 10-16.

132

Int. Biodeterior. Bull. (ISSN 0020.6164) 15 (4) 1979.

BOOK REVIEWS

HANDLING, TRANSPORTATION AND STORAGE OF FRUITS AND VEGETABLES. Volume I , Vegetables and Melons. Second Edition, 1979 SBN 0-87055-115-9. 587 + vii. Westport, Connecticut, Avi Publishing Co.

Only a few days before receiving this volume for review my colleagues and I had been regretting the absence of a new edition of this most useful treatise, and then the first volume arrived. We are now eagerly awaiting the second volume.

This comprehensive work by Ryall and Upton covers the biological, physiological and physical aspects of marketing fresh fruits and vegetables. This is what the authors bashfully claim but, in fact, they cover these aspects theoretically, mechanically, and practically to such a degree that it could be claimed that they include almost all areas of harvesting, packaging, transportation and storage of horticultural food crops. They even include water chestnut.

Physiological and phytopathological injuries suffered after harvest, including the injuries suffered by plants due to manhandling, are considered and described together with techniques for minimising damage.

The physiological and pathological reasons behind the adoption of various post-harvest handling methods are outlined, and references are included. Graphs, tables and advice on such matters as construction of stores and vehicles, calculation of refrigeration capacity required, and heat output by fruits and vegetables, are also neatly presented.

Economic information is not given, deliberately, as economics change whereas scientific facts remain at least moderately constant.

This book has proved itself to be useful, not only as a reference book but also as a comprehensive and intelligible textbook for undergraduate and graduate students interested in the subject. This edition contains matter not available when the first edition was published in 1972, and sections have been revised and brought up to date. The format and layout have been relaxed to make for easier reading. This is partly responsible for the increase in the number of pages from 4 73 in Volume I of the first edition to 587 in the same volume in the second edition. This new edition is certainly easier to read.

In summary, this book is physically well-made and produced. It is academically sound and it fills a need felt by many working in this field. It is pleasing to have a new edition of this valuable work and the authors are to be complimented.

P .H. Lowings.

133

CROP CONSERVATION AND STORAGE M.J. Nash. pp 393 +xi. Pergamon, Oxford, England. £27 50 (liard cover), £8.80 (Fiexicover ).

In spite of scepticism in some quarters, this reviewer has no doubt that 'Conservation and Storage' is a subject in its own right. Dr. Nash certainly thinks it is and he therefore set himself the very considerable task of reviewing these areas of crop technology as thorougltly as possible, limiting himself only by his sub-title: 'In Cool Temperate Climates'. Even within this limitation there are omissions, partially made good by two appendices, a short one on seed storage (J.R. Thomson) and a slightly longer note on fruit storage (R.O. Sharples). This book is therefore a review of the conservation and storage of grains, green crops, potatoes, and sugar beet; still a wide enough range for one man to deal with adequately.

This choice of subject matter reflects not only Dr. Nash's own interest in conservation as a major factor, perhaps the major factor, in the feeding of mankind, but also the relative economic value of these very important crops.

It must be said straight away that Dr. Nash has done very well. He has approached his considerable task very systematically, dealing first with the crop itself, then with its characteristics as a storable commodity, and then with the principles and practice of storage technology throughout Europe and with plenty of reference to practice in U.S.A. and in New Zealand and Australia. Dr. Nash's interest in history is evident at every stage. He has an introductory chapter of absorb­ing interest in which he reviews much of what is known (and conjectured) of storage technology, especially of cereals, in prehistoric, historic, and more recent times. In dealing with each of his chosen crops he frequently refers to past practice and generally his account of modern technology is approached through an historical review.

This book is easy and pleasant to read but it is also a useful book of reference because it has an immense amount of information which is made conveniently accessible by a generous index and long and detailed chapter headings some of which run to two or more pages. It is very desirable, and easy, reading for students and will be very useful to advisers and some agricultural­ists for reference. Not only will it be useful to advisers, they will also enjoy dipping into it.

In general the technology, past and present, is presented in a context of scientific principle although this reviewer was sometimes disappointed by a reluctance to base this on the fundamental facts of the case in quite a number of instances. But within its size,

Int. Biodeterior. Bull. (ISSN 0020.6164) IS (4) 1979.

so wide a subject spread precludes a full discussion of principles in every instance and this book is not intended as a base text for research workers. It is instead a very useful and attractive text, well written and well produced which must be welcome to all concerned with food and agriculture in temperate climates.

T.A. Oxley.

INDUSTRIAL TIMBER PRESERVATION J.G. Wilkinson 532 + xl London, Associated Business Press. (The Rentokil library) £10.00.

This is a beautifully produced book, planned, written and illustrated for a very particular readership, namely the technical staff of wood preservation plants. It is intended to give the man who operates such a plant, who may have no specialised knowledge at all of the process when he begins, everything he needs in a single volume.

In its size, its comprehensiveness, its beautiful and abundant illustration it is clearly the best yet in the Rentokil library. It is written by a professional science writer specifically to be an 'easy read' yet it is technically accurate and nowhere talks down to its readers. It is not for the scientist, yet this reviewer has had it on his shelf for nearly a year and has referred to it quite frequently as the quickest and easiest source of information on wood preservation technology in a wide sense. Any young man who intends to make his career in the field of timber preservation would be very well served by a present of this book. If he reads it conscientiously, and he won't fmd this difficult, he will be very thoroughly informed on all aspects of his chosen trade.

Part 1 gives basic biological and timber industry information. Part 2 explains the basic principles of preservation, the importance of permeability, the various processes and the various preservatives, including useful information on the development and testing of new materials and processes. This is the main body of the book. Finally, Part 3 gives an interesting brief history of timber preservation.

A feature of this book which contributes greatly to its immediate attractiveness is the great number of specially drawn illustrations, all printed in a dark sepia colour, or with a background of this colour. Most of these contribute to the understanding of the subject matter but a few must be regarded as purely decorative and barely relevant. There is also an abundance of half tone illustration most of which are also relevant and helpful, occasionally only supplementary and space­ftlling. There are six very informative appendices.

The publishers and author deserve considerable praise for this volume.

T.A. Oxley.

134

BIOLOGY OF THE FUNGI Ian K. Ross. 499 + xli SBN 0.07.053870-X New York, McGraw Hill. (McGraw Hill series in Organismic Biology).

One is often a little unsure what "The Biology of . ... " is going to unfold to us, but Professor Ross

leaves us in no doubt, as he has expanded the title "Biology of the Fungi" by adding: '"Their development, regulation and associations". As such it is a very readable and useful book. The first third of the book surveys the fungal kingdom generally, emphasising the different patterns of life cycle which operate. The second part is concerned with development and regulation and here there are a number of topics which are of importance in biodeterioration such as spore germination, hypha! growth, heterokaryosis and para­sexuality. The final third of the book is entitled ''Fungal Associations". Unfortunately, 'Decay' under "Natural Roles" is covered by only one paragraph in an awkwardly added chapter entitled "Molds, Mushrooms and Man". Perhaps it would have been more apt if this had been mentioned in a previous chapter on "Saprobes".

This is a very valuable book for those concerned with a fuller understanding of fungally caused deterioration or biodegradation, and as such is to be highly recommended as a readable and relevant text.

H.O.W. Eggins.

INDEX TO VOLUME 15

SUBJECT INDEX

Agricultural chemicals screened for use as wood preservatives ............... .

Algicidal properties of biocidal washes ..... . Aluminium alloy, microbial corrosion and

pitting potential ................ . Aluminium and its alloys in fuel/water systems

corroded by microorganisms ......... . Arsenic, copper and chromium, flxation in wood ..

Part No. Page

. .I:

.. 3:

.4:

. 2:

.3:

9 84

125

39 66

Bacteria, enumeration in wood . . . . . . . . . . . . .4: 119 Benzylphenols evaluated against molluscan borers 2: 49 Biocidal washes, test methods for algicidal properties 3: 84 Biodegradability, a repetitive die-away test . . .2: 57 Borers, wood extractives evaluated for control . . .1: 19

Chaetomium globosum growth and reproduction influenced by temperature and culture medium .•. 3:

Chromium, copper and arsenic fixation in wood . .3: Conservation an4. storage of crops (Book review). .4: Co-oxidation of 2,4-D by Pseudomonas sp. . . . .2: Copper, chromium and arsenic flXation in wood . .3: Copper-chrome-arsenic (CCA) treated poles. . . . .4: Copper tolerance of ship-fouling algae: modified test 1: Corrosion of aluminium alloy, microbial. . . . .4: Crop conservation and storage (Book review) 4: Culture medium and temperature,effect on

Clzaetomiwn globosum. . . . . . . . . . . . .3: Cutting fluid preservatives affected by filtering

agents . . . . . . . . . . . . . . . . . . . . . . . .3: Cutting fluid preservatives potentiated by DTPA

(diethylene triamine pentaacetic acid) . . . .1:

Decay technique, laboratory, using Serpula /acryrnans . . . . . . . . . . . . . . . . . . . .2:

Deterioration of maize by insects and fungi . . .3: Die-away test, repetitive, for biodegradability. . .2: Diethylene triamine pentaacetic acid (DTPA). . .1: DTPA (diethylene triamine pentaacetic acid)

potentiates cutting fluid preservatives . . . . .1:

Filtering agents, effect on activity of preservativtls in cutting fluids .................. .

Fixation of copper, chromium and arsenic in wood Fruits and vegetables, handling, storage and trans-

portation (Book review) ............ . Fuel/water systems contaminated with micro-

organisms, effect on aluminiUm and its alloys. Fungi and insects deteriorating Indian red peppers-Fungi, biology of (Book review) ......... . Fungi translocating nitrogen to wood . . . . . . . Fungi, wood extractives evaluated for control of .

Handling, transportation and storage of fruits and vegetables (Book review) ....... .

Hazardous material spills (Book review) ... .

Industrial chemicals screened for use as wood preservatives . . . . . . . . . . . . . . . . . .

Insects and fungi causing biodeterioration of Indian red peppers ........ .

Insects and fungi deteriorating maize ...... .

.. 3:

.. 3:

.. 4:

.. 2: 3:

. . 4:

.. I:

. .I:

.4:

.I:

.I:

.3: .. 3:

78 66

53 66

113 17

125 133

78

88

I

45 74 57

I

88 66

133

39 96

29 19

133 37

9

96 74

Part No.

Maize in commercial stores deteriorated by insects and fungi ...................... .3:

Microbial effect on aluminium and alloys in fuel/ water systems .................. .2:

Microbiology (Book in Russian reviewed) .... .3: Molluscan borers, benzylphenols evaluated as a

control ...................... .2:

Nasutitennes, three species evaluated for laboratory tests ...............•......... .4:

Nitrogen control and removal from sewage (Book review) .................... .I:

Nitrogen translocated to wood by fungi ..... .I:

Peppers, Indian red, deteriorated by insects and fungi ........................ .3:

Phosphorous control and removal from sewage (Book review) ................... .1:

Pitting potential used to study microbial corrosion of aluminium alloy . . . . . . . . . . . . . . . . . .4:

Preservation of timber (Book review) ......... .4: Preservatives in cutting fluids affected by filtering

agents ................. .3: Pseudomonas sp. co-oxidising 2,4,-D ........ .2:

Screening of agricultural and industrial chemicals as wood preservatives. . . . . . . . . . . . . .1:

Screening technique for algal copper tolerance modified . . . . . . . . . . . . . . . . . . . . .1:

Seawater in culture medium, effect on 01aetomium globosum. . . . . . . . . . . . . . . . . . . . . . . .. 3:

Serpula /aery mans used in laboratory decay technique . . . . . . . . . . . . . . . . . . . . . . .2:

Soft rot fungi from CCA treated poles . . . . . . . .4: Spills of hazardous materials (Book review) . . . . .1: Storage and conservation of crops (Book review). .4: Storage, handling and transportation of fruits

and vegetables (Book review) .4: Streptococci (Book review) . . . . . . . . . . . .1:

Tasmania, soft rot fungi in transmission poles. Temperature and culture medium effect on

Chaetomium globosum . .......... . Termites for laboratory tests .......... . Termites, wood extracts evaluated for control . Test methods for algicidal properties of biocidal

washes ................ , .... . Timber preservation (Book review) ....... . Translocation of nitrogen to wood by fungi .. . Transportation, handling and storage of fruits

and vegetables (Book review) .....•.

Water chemistry (Book review) ....... . Wood, enumeration of bacteria in ...... . Wood extractives evaluated as anti·borer, anti·

termitic and anti·fungal agents ....... . Wood, nitrogen translocated into from the soil

by fungi .................... . Wood preservative, fixation in hardwoods and

softwoods ................. . Wood preservatives, screening of agricultural

and industrial chemicals . . . . . . . . . .

.. 4:

.3:

.4:

.1:

.3:

.4:

.I:

.4:

.I:

.4:

.I:

.1:

.3:

... I:

Page

74

39 104

49

105

38 29

96

38

125 134

88 53

9

7

78

45 113 37

133

133 37

113

78 105

19

84 134

29

133

38 119

19

29

66

9

AUTHOR INDEX on next page.

135

AUTHO.RINDEX Part No. Page

Akinlade, E.E ...... 3: 74 Eggins, H.O.W . . . . . 4: 134 Line, M.A .. ..... .4: 113 Salvarezza, R.C .. . . . 2: 39 La wings, P .H. . . . . .4: 133 4: 125

Bauer, S.R .. ...... 2: 53 Hawkes, H.A . .... . 1: 38 Seenappa, M . . . . . . 3: 96 Bennett, E.O . .... . 1: I Hedley,M.E .. . . . . . 1: 9 Mete, M.F.L. de. ... 2: 39 Shewan,J.M . . . . . . 3: 104 Blok,J. . . . .... .2: 57 Hegarty, B .. . . . . . . 3: 78 4: 125 Stobbs, L.W ....... 3: 96 Bultman, J.D ..... .1: 10 Henshaw, B. . . . . . .3: 66 Morton, L.H.G . ... .3: 84

2: 49 Hawick, C.D. . ... 4: 105 Thornton, J.D . . . . . 2: 45 Butcher,J.A. ... .I: 9 Onyekwelu,I.U .. .. .3: 88 Traxler, R.W . . • . . . 2: 53

Ivbijaro,M.F .. ... .3: 74 Ososamya, E.O .. .. . 3: 74 Carey, Jan ice .... . 4 119 Izzat, I.N. . . . . . . . 1: I Oxley, T.A . ...... 4: 133 Videla, H.A •...... 2: 39 Clark, E.R .. . . . . . . I 38 4: 125 Creffield, J .W. . . ... 4 105 Jurd, L. . .. . .. . . . 2: 49 Parrish, K.K .. .... . 1: 19 Cross, DJ .. ..... . 1 9 Preston, A.F. ..... 1: 9 Waite,J .... ... .. I: 29 Cruickshank, R.H . . . 4 113 Kempton, A.G . ... .3: 96 Wood,E.M. ... . .2: 53 Cumberland, R.F .... 1 37 King, B. .. . ..... I: 29 Russell, G . ...... .I: 7 Curran, P.M.T .. ... .3 78

136

LITERATURE COLLECTION

BIODETERIORATION CENTRE THE UNIVERSITY OF ASTON IN BIRMINGHAM

ST. PETER'S COLLEGE SALTLEY

BIRMINGHAM B8 3TE, ENGLAND.

Telephone: 021-328 5950 Telex: 336997

The Centre collects all literature on the deterioration of materials of economic Importance by living organisms. Retrieval from this collection is the basis for the rapid answer of enquiries.

ENQUIRY SERVICE The Centre offers internationally a confidential detailed question answering service on all aspects of biodeterioration.

Telephone or postal enquiries are accepted. Bibliographic lists can also be compiled in response to enquiries. All enquiries which involve a literature search will be charged at £20 each Inclusive of photocopying up to 40 pages

(anything over 40 pages will be charged at the rate of 12p per page). If the search time involved exceeds 2 hours subsequent time will be charged at £10 per hour. British enquirers will be advised by telephone if it is found that more than 2 hours or extra photocopying is needed. Overseas enquirers will be sent the results of up to 2 hours' work and up to 40 pages of photocopying, if appropriate, and advised if further work is likely to yield further results.

PHOTOCOPY SERVICE The Centre will supply single copies of papers from the literature collection at a cost of 12p per page, minimum

charge £1 (U.K.), £2 (Overseas), providing that a photocopy declaration is signed in compliance with the 1956 British Copyright Act.

CONTRACT RESEARCH The Centre undertakes a wide variety of contract research projects including testing of products by standard or

specially developed methods. Organisms available for use in research and testing include a comprehensive collection of micro-organisms, insects including termites, and a colony of wild strain mice. Contract research rates are very competitive. SPECIALISED BIBLIOGRAPHIES

Special bibliographies on specific aspects of biodeterioration and biodegradation are produced from the document collection from 1965. See the advertisement in this issue.

JOURNALS (>UBLISHED BY THE CENTRE Three quarterly journals are published:-

International Biodeterioration Bulletin UBB) A scientific journal for publication of original works, including reviews and book reviews on all aspects of biodeterioration and biodegradation. Each issue also contains the Biodeterioratlon Society Newsletter which includes short abstracts of papers presented at meetings of the Society in Great Britain and Ireland, and also details of forthcoming meetings, conferences and symposia.

Biodeterioration Research Titles (BRT) A bibliographic journal which presents, in classified form, references to pub· lished literature on all aspects of biodeterioration and biodegradation. About 2000 references per annum.

Waste Materials Biodegradation Research Titles (WMB) A bibliographic journal similar to BRT dealing with all aspects of the biological treatment of solid and liquid wastes and the biodegradation of waste materials in nature. About 1800 references per annum.

PERSONAL CALLERS AT THE CENTRE The Centre welcomes visitors. Visitors may search the document collection free of charge but a charge of 12p per

page will be made for photocopies of any documents taken.

Standard Rate

Reduced Rate

SUBSCRIPTION RATES

International Biodeterioration Bulletin (IBB). per annum Biodeterioration Research Titles (BRT), per annum Both of the above, per annum Waste Materials Biodegradation (WMB). per annum

for private individuals, members of the Biodeterioration Society, who undertake that they do not purchase on behalf of an Institution IBB per annum BRT, per annum Both IBB and BRT, per annum

1980

£26 £22 £42 £20

£15 £13 £25

Sustaining Associates subscribe at the rate of, per annum £100 and receive all three journals io a maximum of 12 copies in any combination of each issue. They are entitled to advice and specialist visits at preferential rates.

Microfiche All three journals are published simultaneously in microfiche at the same subscription rates.

Back Copies Back copies of most issues are available. All issues are available in microfiche.