Final Report Evaluation of alternative sprout suppressants · Spearmint oil was effective at 6°C, but sprout control was inconsistent at the warmer storage temperature. On the basis

Final Report

Evaluation of alternative sprout suppressants

Ref: R438 a component of Defra programme FO/0217

Reporting Period: 2010-2014

Report Authors: Report by: Graeme Stroud & Adrian Briddon, Sutton Bridge Crop Storage Research

© Agriculture and Horticulture Development Board 2014 1

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CONTENTS

1 SUMMARY 4

2 INTRODUCTION 5

3 METHODS AND MATERIALS 6

3.1 Small scale experiments 6

3.2 Large scale (semi-commercial) experiments 10

4 RESULTS 13

4.1 Small scale experiments 13

4.2 Large scale (semi-commercial) experiments 22

5 DISCUSSION 27

6 CONCLUSIONS 30

7 APPENDICES 31

7.1 Additional sprouting data 31

7.2 Records of application to small scale chambers 33

7.3 Product labels 37


1 SUMMARY

Cultivars Russet Burbank and Saturna were held in small-scale chambers at

6°C and 9°C for periods up to approximately 3 months and 6 months, over

three storage seasons. A range of sprout suppressants were applied, as cold

mists, and efficacy of sprout control assessed in comparison with CIPC

applied once, as a liquid, directly to tubers at store loading.

CIPC resulted in effective, commercially acceptable sprout control of both

cultivars, at both storage temperatures and in all seasons. Of the alternative

sprout suppressants, over three seasons, caraway oil was relatively effective,

but control was sometimes incomplete during storage at 9°C for 6 months.

Spearmint oil was effective at 6°C, but sprout control was inconsistent at the

warmer storage temperature.

On the basis of small-scale work, caraway oil and spearmint oil were selected

for assessment in semi-commercial trials (16 tonnes, in boxes). With caraway

oil applied non-positively and spearmint oil applied using positive ventilation,

sprout control of cultivars Russet Burbank and Saturna was incomplete

during storage at 9°C, under the conditions tested.


2 INTRODUCTION

After an initial dormant period, sprouts grow from stored potatoes. Unchecked,

sprouting gives rise to internal changes that eventually render the crop unsaleable.

Such changes include excessive weight loss, shrinkage and deterioration in

processing quality. Suppression of sprout development during storage, especially at

the warmer temperatures used for processing, is critical. CIPC is the main active

substance for the control of sprout growth, and in 2008 was used on around 47% of

stored potatoes in Great Britain (Garthwaite et al. 20091) and made up 94% of post-

harvest treatments to stored potatoes.

Alternative sprout suppressants are being sought and treatments are becoming

available. To date, only post-harvest treatment with ethylene has had significant

commercial success (www.pesticides.gov.uk/approvals.asp?id=271). It was used on

4% of stored crops in 2008 (Garthwaite et al. 2009). Treatments with ethylene

currently are limited to the fresh potato sector, because of the associated potential

deterioration in processing quality.

Essential oils have been recognised as sprout suppressants for many years and are

available formulated as products for sprout control (and other applications)

elsewhere. Little independent information is available on the alternatives. This project

(R438) is designed to give comparative information on the efficacy of new active

substances that are available or expected to become available in the near future. An

alternative method of using CIPC (GroStop Ready) is also included. This product is a

liquid formulation which is applied directly to tubers at store loading. Although

available for some years, this method of applying CIPC has never been widely

adopted in the UK, unlike mainland Europe where it is frequently used.

1 Garthwaite, D.G., I. Barker, G. Parrish and L. Smith, 2009. Pesticide usage survey report 227. Potato stores in Great Britain. Food & Environment Research Agency, York, UK. http://www.fera.defra.gov.uk

© Agriculture and Horticulture Development Board 2014

5

http://www.pesticides.gov.uk/approvals.asp?id=271

These studies were funded by AHDB Potato Council as part of a larger programme,

primarily funded by DEFRA (FO/0217: Reducing post-harvest losses and wastage in

UK potato storage due to sprouting).

3 METHODS AND MATERIALS

3.1 Small scale experiments

Experimental work was conducted using 120 litre plastic

chambers (Fig. 1), inside controlled environment rooms at

6 and 9 °C (±0.5). Humidity was not controlled. Netted

samples (total weight ~40 kg) were placed in the

chambers and sealed. Ventilation was by vacuum pump

drawing 2 air exchanges per day as 15 minute bursts

spaced evenly through the day. Contaminated air was

exhausted outdoors to prevent cross-contamination.

Samples of cultivars Russet Burbank and Saturna

shared each chamber.

Season 2010-11 Chambers were loaded, made up to 40.0 kg, sealed and all initial applications made

on 16 December 2010. Untreated samples (not in chambers) were held in separate

stores, at similar target temperatures. Four sprout suppressants were tested.

CIPC (GroStop Ready) was applied at a nominal application rate of 18 g tonne-1

directly to tubers on a roller table using a Microstat ULV spinning disc applicator

(Horstine Farmery, Gainsborough, UK) at store loading. The electrostatic function of

the applicator was not used. No further applications of CIPC were made during

storage.

Essential oil applications were cold misted by airbrush and compressed air at 0.75

bar, through a port in the chamber, into a void beneath the tubers. Ventilation was

discontinued for 24 hours following in-chamber treatments. See Appendix 7.2 for

application details.

Figure 1: Small scale storage chamber showing ventilation pipe.

Spearmint oil (Biox-M) was applied initially at a rate of 90 ml tonne-1, followed by

applications at 30ml tonne-1 at 21 day intervals.

Clove oil (Biox-C) was applied on four occasions, the first two occasions at 48 ml

tonne-1 and then the rate was increased to 84 ml tonne-1. During the final application

a fan was used to recirculate the applied mist through the crop from the application

port, beneath the crop, to a similar port directly above.

Caraway (Talent) was applied at the proposed weekly application rate for Talent on

ware potatoes (initially 30 ml/tonne, reducing by 5 ml every 2 weeks until 15 ml/t and

then at that rate until unloading).

Assessments were carried out in April and July after 16 and 29 weeks storage

respectively. On the first sampling occasion sprout growth (25 tubers) was assessed

and then at unloading sprouting, processing quality (crisps 30 and chips 20 tubers),

pathology and defects (25 tubers).

For crisping, 300 g of slices between 1.22 and 1.47 mm thick were taken from 30

mechanically peeled tubers and washed in water for 45 seconds. Each sample was

then fried for 3 minutes in oil heated up to 177 °C at the start of frying. After frying the

sample was weighed and then crisps with defects (a dark discolouration larger than a

5 mm diameter circle) removed and weighed. The remaining blemish free sample

was then assessed objectively three times using a HunterLab D-9000 colour quality

meter fitted with a D25-L optical sensor [Mountsorrel, Leics., UK].

Chips were processed as single 3/8th inch square longitudinal sections from each of

20 sound tubers and fried for 90 seconds in oil heated up to 190°C at the start of

frying. The fry colour of individual strips was assessed subjectively by comparison

with a USDA standard colour chart [Munsell Color, Baltimore, Maryland, USA] under

standard artificial white light. The USDA assessment scale used for assessing chips

(light to dark - 000, 00, 0, 1, 2, 3 & 4) was linearized 1 to 7 (SBCSR scale) and

reported as a mean. Scores of 1 to 3 are good; scores of 4 and 5 acceptable and

higher scores rejected.

Season 2011-12 In the second year of the study, the same treatments were applied as previously but

with the addition of 3-decen-2-one (SmartBlock). All chambers were made up to

42.0 kg of tubers and from here onward the untreated samples were also stored in

ventilated chambers. Chambers were loaded on 9th November 2011.

CIPC (Gro-Stop Ready) was applied similarly to last season but, from 2011-12

forward, by Mafex Mantis spinning disc applicator, over a conveyor belt. Spraying

took place on 18th November 2011.

The additional treatment of 3-decen-2-one (SmartBlockTM) was applied at a rate of

115 ml tonne-1 when either cultivar showed a sprout incidence of approximately 75%.

The application method was the same cold misting technique used for caraway,

clove and spearmint oils. One SmartBlockTM application was made to the 6 °C crop

on 27th January 2012 and four applications were made to the 9°C crop on

9th December 2011, 27th January 2012, 16th March 2012 and 14th May 2012.

Assessments were carried out in April and July after 14 and 29 weeks storage,

respectively. On the first sampling occasion sprout growth (40 tubers) was assessed

and then at unloading sprouting, processing quality (chips 20 and crisps 30 tubers),


In year 1, the use of clove oil did not result in sprout control. This was discussed with

approval holders in the USA (PIN/NIP and Pace). In year 2, modifications were made

to improve ‘contact’ between mist and sprout tissue by recirculation and by

increasing volatility (through raising temperature). However, after two applications, at

48 ml tonne-1, control was still not evident so applications and assessment of this

treatment was discontinued after the first sampling occasion. This treatment was not

tested again in this study.

Season 2012-13 Chambers were loaded to a combined crop weight of 40.0 kg on 6th November 2012.

This season’s trial was a repeat of the previous setup with the addition of an

irradiation treatment of 15 kJ of short wave ultra violet light or UV-C (100 - 280 nm).

Custom made irradiation equipment was supplied by Cranfield University. Tubers

designated for this treatment were removed from their chambers, placed rose end

up, and exposed to the light for 11 minutes on 5th December 2012.

CIPC was applied on 22nd October 2012. SmartBlockTM was applied twice to the 9°C

crop on 31st January 2013 and 21st March 2013, respectively and once to the 6°C

crop on 8th April 2013. Caraway and spearmint were applied regularly as before.

Assessments were carried out after 12 and 26 weeks storage. On the first sampling

occasion sprout growth (40 tubers, as previously) was assessed and then at

unloading sprouting (40 tubers), processing quality (chips 20 and crisps 30 tubers),


Due to an extended cold period, moist air drawn out from the chambers in the 9 °C

store condensed excessively and ran back into store accumulating in the u-bends

formed by fastening the pipework. This inhibited air flow enough to damage tuber

quality with anaerobic conditions resulting in dark fry colours and blackheart. These

data were discarded and, consequently, it was decided to repeat the 9 °C experiment

the following season (2013-14).

Season 2013-14 This experiment was intended to be a repeat of the 9 °C part of the previous

season’s work. However, the UV-C irradiating equipment failed irreparably during

normal operation and this treatment was not pursued further. CIPC was applied and

chambers loaded on 11th October 2013. SmartBlockTM was applied three times on

17th January 2014, 17th March 2014 and 3rd April 2014, respectively. Assessments

were carried out after 16 and 25 weeks storage. All other variables replicated the

previous season.

Table 1. Sprout suppressant products/formulations applied in study

Table 2: Treatment summary

treatment year 1 year 2 year 3 year 4

2010-11 2011-12 2012-13 2013-14

6°C 9°C 6°C 9°C 6°C 9°C untreated CIPC caraway spearmint clove

3-decen-2-one

UV-C

3.2 Large scale (semi-commercial) experiments

Season 2011-12 Caraway oil (S-carvone) Treatments and experimental design Cultivar Saturna was stored in 16 one tonne pallet boxes in a single experimental

store at 9.0°C. Netted sub-samples of cv Saturna and Russet Burbank were placed

within the bulk crop in defined box locations (front/back, left/right, top/upper-

middle/lower-middle/bottom). Eight nets were buried within designated boxes for

each cultivar and for each assessment occasion. The experimental design was an

unreplicated comparison of treatments with variation measured by eight in-store

replicates.

Store set-up and control The 16 tonne capacity Controlled Environment Room (CER) was configured with air

discharged above boxes (overhead throw) and recirculated back through pallet

spaces beneath boxes. Boxes were stacked 4 high as a solid block of 4 columns. No

chlorpropham (CIPC) sprout suppressant had ever been used in the store.

active substance formulation / product supplier

CIPC GroStop Ready Certis Europe

caraway oil / S-carvone Talent Makhteshim Agan

clove oil / eugenol Biox-C Xeda international

spearmint oil / R-carvone Biox-M Xeda international

3-decen-2-one SmartBlockTM Amvac


At the beginning of storage, crop temperatures were pulled-down at a rate of 0.5 °C

per day until the holding temperature of 9 C was achieved (tolerance ± 0.5 °C).

Humidification, by wet cell, was then enabled at 95% RH (tolerance ± 5%) on 16th

November 2011.

Chemical application Caraway oil (Talent, Makhteshim Agan - Benelux) was applied using a Dyna-Fog

(Curtis Dyna-Fog, Dayton, Ohio, USA) cold fogging system, located in the store

headspace. At the time of application refrigeration was turned off, and store air

recirculated continuously for a period of 24 hours before returning to automatic

control. Talent was applied at the proposed EU ware label rate every 7 days

beginning on 18th November 2011 and ending on 27th April 2012 (final application).

The first two applications were made at 30 g/tonne, the second two at 25 g/tonne and

the third two at 20 g/tonne. All subsequent applications were at 15 g/tonne.

Assessments The longest sprout length and number of sites of sprouting were measured on 25

tuber sub-samples at intake and after 12 and 24 weeks of storage (unloaded 14th

February 2012 and 10th May 2012 respectively). Fry colour was measured as chips

(French fries) for Russet Burbank and crisps for Saturna at intake and 24 weeks

using the same frying methods as in the small scale experiments. Pathology and

defects were scheduled for assessment at 24 weeks only.

Season 2012-13 Spearmint oil (R-carvone) Treatments and experimental design Cultivar Russet Burbank was stored in 16 one tonne pallet boxes in a single

experimental store at 9.0 °C. Netted sub-samples of cvs Russet Burbank and

Saturna were placed within the bulk crop in defined box locations (front/back,

left/right, top/upper-middle/lower-middle/bottom). Eight nets were buried for each

cultivar and for each assessment occasion. The experimental design was an

unreplicated comparison of treatments with variation measured by eight in-store

replicates.

Store set up and control A 16-tonne box capacity Controlled Environment Room (CER) was configured for

positive ventilation, with alternate pallet slots blocked and air discharged from a

plenum chamber. Boxes were stacked 4 high as a solid block of 4 columns. Air was

recirculated through a conditioning duct for refrigeration, heating or humidification as

necessary. No chlorpropham (CIPC) sprout suppressant had ever been used in the

store.

After store loading, crop temperature was pulled-down at a rate of 0.5 °C per day

until the holding temperature of 9.0 °C was achieved (tolerance ± 0.5 °C).

Humidification by wet cell was then enabled at 95% RH (tolerance ± 5%) on 13th

November 2012.

Chemical application Spearmint oil (Biox-M, MAPP No. 16021) was applied using a Cedax EW 3000

Electrofog (Xeda International, Saint-Andiol, France) discharging directly into the

store plenum chamber. At the time of application refrigeration was turned off, and

store air recirculated constantly for a period of 24 hours before returning to automatic

control. Biox-M was applied at the label recommended rates every 21 days,

beginning on 15th November 2012 and ending on 11th April 2013 (final application).

The first application was at 90 g/tonne with all subsequent applications at 30 g/tonne.

Assessments The longest sprout length and number of sites of sprouting were measured on 25

tuber sub-samples at intake and after 14 and 26 weeks of storage (unloaded 29th

February 2013 and 19th April 2012, respectively). Fry colour was measured as chips

(French fries) for Russet Burbank and crisps for Saturna at intake and after 26 weeks

using the same frying methods as in the small scale experiments. Pathology and

defects were assessed at 26 weeks only.

4 RESULTS 4.1 Small scale experiments Sprouting

The mean longest sprout lengths per tuber (mm) are shown in Tables 3 and 4 for

cultivars Saturna and Russet Burbank, respectively. Sprouting up to 10 mm might be

acceptable for processing; lengths in excess of this would normally be rejected.

Figures demonstrating excessive sprouting in the tables are shaded red.

First year (Season 2010-11) At 6°C, sprout control in Saturna was effective using CIPC, caraway and spearmint.

Sprout length was excessive on both sampling occasions using clove oil. With

Saturna at 9°C, only treatment with CIPC maintained sprouting at an acceptable level

at unloading.

Sprouting in Russet Burbank gave broadly similar results but with apparently lower

sprouting pressure. At 6°C no sprout control was required to maintain acceptable

sprouting at sampling occasion 1 (16 weeks). However, by unloading sprouting was

only effectively controlled by CIPC, caraway and spearmint (although the latter was

significantly less effective than the former two). Clove oil was never effective. At 9°C

only CIPC and caraway were effective at controlling sprout growth. Even at the first

sampling occasion sprout growth was excessive using spearmint and clove oils.

Second year (Season 2011-12) During storage at 6°C, all treatments resulted in very effective control of sprouting in

both cultivars. This was especially effective in Russet Burbank with mean longest

sprout lengths less than 3mm at unloading (29 weeks). Sprouting in Saturna was

also well controlled at 6°C across all treatments, with sprout lengths much less than

the 10mm threshold.


Table 3: Length of the longest Saturna sprout (mm).

temperature sampling occasion suppressant

year 1 year 2 year 3-4* length sd length sd length sd

6 °C

1

untreated 21.0 7.7 14.2 9.5 0 0.2 CIPC 1.4 1.3 1.8 1.1 0 0.2 caraway 0.2 0.4 0.4 0.5 0.1 0.2 spearmint 2.9 1.1 1.5 0.8 0 0 clove 18.1 9.5 3-decen-2-one 0.7 1.1 0 0 UV-C 0 0

2 unloading

untreated 41.7 15.4 41.9 9.9 11.8 5.9 CIPC 2.2 1.4 3.7 4.8 0.3 0.9 caraway 1.2 0.6 0.5 0.5 0.1 0.3 spearmint 8.3 3.6 1.4 0.7 2.0 1.4 clove 40.7 9.4 3-decen-2-one 5.8 4.2 1.8 4.0 UV-C 11.2 4.9

9 °C

1

untreated 40.8 4.8 69.3 29.4 19.3 6.6 CIPC 5.5 6.6 2.8 1.6 2.3 0.9 caraway 1.0 1.2 1.4 1.0 2.6 2.5 spearmint 31.0 5.9 15.2 6.0 21.7 9.2 clove 35.6 8.1 3-decen-2-one 2.6 3.5 0.8 1.9

2 unloading

untreated 62.9 11.3 44.4 17.5 42.8 20.1 CIPC 9.9 19.2 4.8 6.4 2.0 1.0 caraway 23.1 12.7 4.1 5.4 16.1 15.9 spearmint 44.8 17.9 22.5 7.4 38.7 13.4 clove 60.5 19.2 3-decen-2-one 18.2 10.5 11.0 7.9

* = 6 °C year 3 (season 2012-13) and 9 °C year 4 (season 2013-14)

The potential for sprout growth was considerably greater during storage at 9°C, with

untreated samples of both cultivars having excessive sprout growth at the first

sampling occasion. In Saturna, sprouting was most effectively controlled using CIPC

and caraway. There was little difference between the sprout control treatments for

Russet Burbank with all treatments limiting sprouting to less than 3mm except

spearmint at unloading (7.9 mm, but variation was high).


Table 4: Length of the longest Russet Burbank sprout (mm).


year 1 year 2 year 3-4* length sd length sd length sd

6 °C

1

untreated 10.0 7.8 1.2 2.4 0 0.2 CIPC 0.7 0.6 0.3 0.6 0 0 caraway 0 0 0 0 0 0.2 spearmint 2.0 3.1 0.2 0.5 0.2 0.6 clove 6.8 8.3 3-decen-2-one 0 0 0 0 UV-C 0.1 0.2

2 unloading

untreated 25.7 16.8 10.0 6.4 3.9 4.2 CIPC 1.6 0.7 2.2 1.8 0.4 0.8 caraway 1.0 0.3 0.9 0.3 4.5 6.8 spearmint 9.0 4.2 1.0 0.2 2.8 2.5 clove 46.4 16.5 3-decen-2-one 0.6 0.5 1.1 2.4 UV-C 4.3 3.8

9 °C

1

untreated 28.9 12.3 25.3 24.8 16.0 13.3 CIPC 1.6 0.8 0.9 0.7 0.6 0.9 caraway 0.3 0.5 0.5 0.6 5.0 7.0 spearmint 38.2 12.3 2.1 1.1 8.9 8.1 clove 27.3 17.3 3-decen-2-one 0.6 1.2 0 0

2 unloading

untreated 95.6 25.1 13.0 13.3 54.5 55.3 CIPC 7.7 14.8 1.6 2.3 1.0 0.2 caraway 8.6 11.9 1.0 0.2 25.2 27.9 spearmint 102.3 39.6 7.9 6.8 22.5 15.2 clove 118.1 40.2 3-decen-2-one 2.9 4.5 20.0 21.2 * = 6 °C year 3 (season 2012-13) and 9 °C year 4 (season 2013-14)

Third year (Season 2012-13) 6°C only There was very low sprouting pressure at sampling occasion 1 (14 weeks) with low

incidences (See Appendix 8.1, Table 22). However, by unloading (25 weeks) the

mean longest sprout in untreated Saturna had grown to a commercially unacceptable

11.8 mm. All suppressant treatments were effective on Saturna except UV-C (11.2

mm at unloading). However, CIPC and caraway were especially effective with final

values of 0.3 and 0.1 mm, respectively. The mean lengths of the longest sprout in

Russet Burbank were all commercially acceptable at this storage temperature but

CIPC was particularly effective (0.4 mm at unloading).


Fourth year (Season 2013-14) 9°C only After 15 weeks (sampling occasion 1) sprouting in Saturna was only adequately

controlled by CIPC, caraway and 3-decen-2-one. By unloading only CIPC was still

commercially effective with a mean length of 2 mm.

At the first sampling occasion all Russet Burbank treatments adequately controlled

sprouting, especially CIPC and 3-decen-2-one (0.6 and zero mm, respectively). As

for Saturna, by unloading at 25 weeks, only CIPC effectively controlled sprouting in

Russet Burbank with a mean longest sprout length of 1 mm.

Saturna crisp assessment A weight of crisps with defects of <5% would be considered low and greater than

15% unacceptable. Where crisp fry colour is assessed by Hunter Lab, values greater

than L 59 are considered commercially good, between L 59 and L 49 may be

acceptable but less than L 49 would be rejected. The results in Table 5 are shaded

green for commercially good and red for unacceptable.

Table 5: Percentage weight of Saturna crisps with defects and Hunter L lightness value.

temp suppressant year 1 year 2 year 3-4

defects Hunter L sd defects Hunter L sd defects Hunter L sd

6 °C

untreated 15.3 53.4 0.1 75.7 – – 81.2 – – CIPC 9.2 54.4 0.4 52.3 48.6 0.3 70.4 – – caraway 27.8 51.6 0.4 86.2 – – 100 – – spearmint 22.5 54.0 0.3 59.5 51.5 0.3 94.1 – – clove 33.7 44.9 0.2 3-decen-2-one 83.2 – – 63.9 – – UV-C 40.1 48.3 0.5

9 °C

untreated 6.9 54.8 0.1 50.3 53.2 0.1 0 63.4 0.1 CIPC 28.5 52.3 0.5 71.3 – – 0 61.4 0.2 caraway 23.7 52.9 0.1 46.9 51.9 0.4 5.8 62.2 0.2 spearmint 5.6 59.4 0.1 40.5 54.4 1.4 4.4 59.6 0.2 clove 9.2 53.6 0.3 3-decen-2-one 43.0 53.6 0.5 1.4 59.9 0.1

( – Where defects are excessive there is not enough remaining sample for Hunter L colour assessment.)

The Saturna crisp processing quality assessment results are shown in Table 5. After

storage at 6°C in season 2010-11, only CIPC resulted in low and acceptable levels of

fry defects. Fry colours were all intermediate except for clove oil which was


commercially unacceptable. At 9°C, CIPC and caraway resulted in high levels of fry

defects but levels under clove and spearmint were acceptable. No fry colours were

unacceptably poor but those of spearmint were maintained at a commercially good

value.

In the season 2011-12, all fry defect levels were unacceptably high at both

temperatures. Fry colours were intermediate where assessment was possible, except

at 6°C under CIPC, which fried unacceptably dark. Only 6°C results are displayed for

the 2012-13 season and these all had unacceptably high defects. It was only

possible to assess the colour of the UV-C treatment and this was poor. During the

season 2013-14, with storage at 9°C only, all treatments generally had low levels of

defects. Those of untreated and CIPC were nil. Most defects were found under

caraway with a borderline value of 5.8%. All fry colours were light and commercially

good.

Russet Burbank chip (French fry) assessment The USDA assessment scale used for assessing chips (light to dark - 000, 00, 0, 1,

2, 3 & 4) was linearised to a 1 to 7 scale (SBCSR score) as shown below (Table 6),

and reported as a mean shown in Table 7. A score up to 3.9 is considered good; 4 to

5.9 borderline, whereas higher scores would be rejected.

Table 6: Chip scale conversion table

SBCSR 1 2 3 4 5 6 7

USDA (standard) 000 00 0 1 2 3 4

Across all seasons at 6°C there were no significant differences in the fry colour of

Russet Burbank chips due to suppressant treatment with all achieving an acceptable,

intermediate colour, except for a commercially good chip score of 3.8 in the untreated

for season 2012-13.

For the crops stored at 9 °C fry colour was generally lighter and commercially good

but again there were no significant differences due to treatment. However, certain

treatments did fall into the intermediate quality category. These were CIPC,

spearmint and untreated in the second season 2011-12.

Table 7: SBCSR lightness score for Russet Burbank chips (French fries)

temperature suppressant year 1 year 2 year 3-4

score sd score sd score sd

6 °C

untreated 4.5 0.5 4.9 0.4 3.8 0.9 CIPC 4.7 0.6 4.9 0.3 4.2 0.7 caraway 4.7 0.6 5.2 0.9 4.4 0.5 spearmint 4.7 0.7 4.8 0.4 4.2 0.8 clove 4.8 0.6

3-decen-2-one

5.5 0.5 4.2 0.8 UV-C

4.4 0.5

9 °C

untreated 3.3 0.4 5.1 0.7 3.1 0.3 CIPC 3.5 0.5 4.3 0.9 3.1 0.3 caraway 3.5 0.5 3.5 0.7 3.3 0.6 spearmint 3.6 0.6 4.1 0.5 3.1 0.2 clove 3.5 0.5

3-decen-2-one

3.8 0.8 3.5 0.9 Pathology and defects Season 2010-11 An unavoidably small sample size (25 tubers) led to wide variation in the data. Silver

scurf (Helminthosporium solani) severity (surface area affected) had particularly wide

variation and incidences were generally high. However, the caraway treated Russet

Burbank at 6 °C was notable for low severity and incidence. Black dot (Colletotrichum

coccodes) severity and incidence ranged more consistently higher than silver scurf

but it was not possible to identify a treatment effect. There were 4 sporadic

incidences of dry rot (Fusarium spp rot) in Saturna and no incidences of any other

store developing disease.

Lenticel discolouration was present on both cultivars at variable but generally high

incidences, no trends emerged. Internal rust spot was found in Russet Burbank only

but again no treatment trends were found. Vascular discolouration was found in four

tubers, all in spearmint treated Saturna. Internal sprouting was frequently found,

occurring in all Saturna treatments at 9°C ranging between 2 tubers with CIPC and

11 tubers with caraway. For the same variety at 6°C there were 2 tubers in both

spearmint oil and clove oil treatments only. Russet Burbank seemed less prone to

the defect with 2 incidences found in both caraway and clove oil treatments at 9°C

only.

Skin damage resembling chemical scorch was seen at low levels under most

treatment regimes on Saturna, especially 6 °C clove oil (7 incidences) and CIPC (5

incidences). None was found in 9°C untreated. However, Russet Burbank only

showed damage on the 6°C CIPC treatment with an incidence of 40% (10 tubers).

There were 3 incidences of glassiness in Russet Burbank each in different

treatments including the untreated. No other defects were detected.

Table 8: Pathology and defect assessment for year 1 (season 2010-11)

cultivar temp. suppres. silver scurf black dot lent

disc. vasc. discol.

intern. sprout skin damage

sev. sd inc. sev. sd inc. inc. inc. inc. sev. sd inc.

Saturna

6 °C

untreat. 11.9 18.2 72.0 33.2 29.9 84.0 48.0 0 0 0 0.2 4.0

CIPC 3.0 5.0 64.0 29.6 27.0 100 68.0 0 0 0.4 1.0 20.0

caraway 2.5 4.9 48.0 21.9 27.0 84.0 68.0 0 0 0.2 0.7 8.0

spearm. 4.4 6.9 68.0 33.7 32.3 84.0 80.0 0 4.0 0.0 0.2 4.0

clove 13.2 14.0 80.0 44.4 26.1 92.0 16.0 0 4.0 1.2 2.3 28.0

9 °C

untreat. 16.3 26.0 52.0 50.5 30.5 88.0 8.0 0 16.0 0 0 0

CIPC 38.7 30.7 92.0 20.4 29.4 64.0 32.0 0 8.0 0 0.2 4.0

caraway 5.0 9.3 44.0 36.8 27.6 92.0 60.0 0 44.0 0 0.2 4.0

spearm. 8.1 17.7 36.0 47.0 29.5 88.0 24.0 16.0 28.0 0.5 1.6 16.0

clove 2.8 8.1 36.0 37.3 30.9 88.0 32.0 0 28.0 0.1 0.7 4.0

Russet Burbank

6 °C

untreat. 2.2 1.9 100 17.2 17.3 84.0 88.0 0 0 0 0 0

CIPC 2.3 3.7 92.0 10.6 14.8 76.0 88.0 0 0 0.7 1.1 40.0

caraway 0.2 0.4 20.0 21.8 24.8 84.0 96.0 0 0 0 0 0

spearm. 5.8 8.1 100 16.0 22.8 72.0 100 0 0 0 0 0

clove 7.0 8.6 96.0 13.6 21.3 88.0 76.0 0 0 0 0 0

9 °C

untreat. 11.4 12.6 100 11.9 17.1 80.0 76.0 0 0 0 0 0

CIPC 1.1 1.1 72.0 13.9 16.2 72.0 88.0 0 0 0 0 0

caraway 4.1 7.4 96.0 23.1 24.5 100 56.0 0 4.0 0 0 0

spearm. 10.7 10.6 84.0 22.3 28.8 84.0 80.0 0 0 0 0 0

clove 2.7 2.9 88.0 12.8 18.5 84.0 40.0 0 4.0 0 0 0

Season 2011-12 Small sample sizes (40 tubers) led to wide variation in the data. Silver scurf generally

had wide ranging severity and high incidences. Little can be inferred from the data

except that both incidence and severity tended to be higher on Russet Burbank.

However, silver scurf severity was noticeably lowest after caraway treatment at both

temperatures.

Black dot incidences and severity were consistently high in the whole trial and no

treatments stood out from the rest. Skin spot (Polyscytalum pustulans) was found on

Saturna as single incidences of very low severity for most treatments including the

control. However, on Russet Burbank only 9°C CIPC had pustules, at 2 incidences

(5%). There was a single incidence of dry rot in untreated Saturna and 4 of gangrene

in Russet Burbank, 2 of which were untreated.

Table 9: Pathology and defect assessment for year 2 (season 2011-12)

Slight lenticel discolouration was present on both cultivars at variable but generally

high incidences, no trends emerged. Slight internal rust spotting was found at low

incidences throughout the trial. Slight vascular discoloration occurred sporadically at

high incidences, the greatest of which was in untreated Saturna at 13 incidences

(34.2%). Internal sprouting occurred in untreated tubers of both cultivars. However,

elevated incidences were seen in 9 °C Saturna treated with caraway, spearmint oil

and 3-decen-2-one at 13, 28 and 30%, respectively.

Skin damage as chemical scorch like symptoms was seen sporadically at low

incidence and severity under all chemical treatments, including untreated, and on

cultivar temp. suppressant silver scurf black dot vasc.

discol. int.

sprout. skin damage

Sev. sd inc. Sev. sd inc. inc. inc. Sev. sd inc.

Saturna

6 °C

untreated 3.0 6.4 85.0 44.8 25.3 97.5 5.0 7.5 0.1 0.2 5.0

CIPC 2.8 6.1 70.0 42.8 26.4 100 0 0 0 0 0

caraway 1.2 3.2 30.8 46.7 26.5 100 2.6 2.6 0 0 0

spearmint 3.8 8.9 42.5 38.1 27.6 100 2.5 0 0.1 0.2 5.0

3-decen-2-one 5.0 9.7 87.5 47.3 24.7 100 2.5 0 0 0 0

9 °C

untreated 2.0 4.4 34.2 37.8 29.5 94.7 34.2 5.3 0 0 0

CIPC 4.0 12.5 68.4 36.4 27.0 97.4 0 0 0.1 0.2 5.3

caraway 3.5 9.9 40.0 42.6 30.3 97.5 2.5 12.5 0.1 0.2 5.0

spearmint 5.8 11.8 51.3 44.8 29.1 97.4 5.1 28.2 0 0.2 2.6

3-decen-2-one 13.8 19.5 85.0 44.7 26.7 97.5 25.0 30.0 0.1 0.2 5.0

Russet Burbank

6 °C

untreated 24.8 23.7 97.5 21.5 23.5 92.5 0 0 0.2 1.2 2.5

CIPC 12.2 12.7 90.0 20.9 23.9 77.5 0 0 0.3 0.8 20.0

caraway 7.9 11.2 87.5 18.2 24.5 95.0 0 0 0 0 0

spearmint 13.6 16.8 87.5 21.2 25.7 82.5 0 0 0.1 0.6 7.5

3-decen-2-one 38.9 25.7 97.5 13.2 15.3 87.5 0 0 0.1 0.6 2.5

9 °C

untreated 35.2 27.0 97.5 23.2 27.1 90.0 0 2.5 0 0 0

CIPC 37.9 29.0 100 15.9 22.6 69.4 2.8 0 0.1 0.3 8.3

caraway 7.9 14.6 67.5 16.0 21.4 75.0 0 0 0.1 0.6 2.5

spearmint 42.7 31.2 100 21.0 23.8 75.0 0 2.5 0 0 0

3-decen-2-one 53.4 25.6 100 18.2 24.8 82.5 5.0 0 0.1 0.6 2.5

both cultivars. However the greatest incidences were found on CIPC treated Russet

Burbank at both 6 °C (20%) and at 9 °C (8%). There were no severe defect

symptoms and no other defects were noticed.

Season 2012-13 A small sample size of 25 tubers gave wide variation in the data. At 6 °C, silver scurf

severity was generally low on Saturna and higher on Russet Burbank but further

discrimination between sprout suppressant treatments was not possible. Incidence

was very high on Russet Burbank but relatively low on Saturna except for untreated

(68%) and SmartBlockTM (60%). Black dot was present at high incidences and

generally high severities with broad variation enough to preclude further analysis.

Also in the trial there was a single incidence of both skin spot and dry rot, 2

incidences of soft rot. No other storage diseases were detected.

Swollen lenticels were found on 4 CIPC treated Russet Burbank tubers only. Skin

damage resembling chemical scorch was found at low severity but high incidences

on CIPC treated Saturna (72%) and Russet Burbank (40%). A few incidences also

occurred with caraway and spearmint treatment. No other defects were detected.

Table 10: Pathology and defect assessment for 3rd year at 6 °C only (season 2012-13)

cultivar suppressant silver scurf black dot soft

rot swoll. Lentic. skin damage

sev. sd inc. sev. sd inc. inc. inc. sev. sd inc.

Saturna

untreated 1.7 2.2 68.0 23.8 20.8 100 0 0 0 0 0

CIPC 0.1 0.3 8.0 24.5 24.3 92.0 0 0 1.0 1.0 72.0

caraway 0.3 0.5 28.0 15.3 19.6 92.0 0 0 0.2 0.4 16.0

spearmint 0.2 0.4 20.0 6.9 9.1 96.0 0 0 0 0.2 4.0

3-decen-2-one 2.3 4.0 60.0 23.0 22.0 96.0 0 0 0 0 0

UV-C 0.5 1.5 20.0 24.1 23.8 96.0 4.0 0 0 0 0

Russet Burbank

untreated 7.4 8.4 96.0 21.1 27.1 96.0 0 0 0 0 0

CIPC 2.3 2.5 88.0 4.0 8.5 68.0 0 16.0 3.1 8.1 40.0

caraway 9.1 15.0 88.0 11.0 13.4 80.0 4.0 0 0 0.2 4.0

spearmint 10.7 11.6 96.0 16.7 19.9 84.0 0 0 0 0 0

3-decen-2-one 14.4 13.5 100 11.8 21.0 92.0 0 0 0 0 0

UV-C 14.5 10.5 100 11.5 11.1 84.0 0 0 0 0 0

Season 2013-14 Silver scurf severity, by surface area affected, was too variable to adequately

compare sprout suppressant treatments due to small sample size (25). Incidences

were generally high (over 50%) on Russet Burbank with all sprout suppressant

treatments and Saturna treated with spearmint (68%) and SmartBlockTM (56%).

Variation in black dot severity was too broad to distinguish between sprout

suppressants but incidences were all high. There was a single incidence of skin spot

in CIPC treated Russet Burbank. No other storage diseases were detected.

Skin damage as chemical scorch like symptoms were found in both CIPC treated

cultivars, especially Russet Burbank with a 100% incidence. Internal sprouting

occurred only in Saturna, 3 times with spearmint and once with caraway. No other

defects were detected.

Table 11: Pathology and defect assessment for 4th year at 9 °C only (season 2013-14)

cultivar suppressant silver scurf black dot int.

sprout skin damage

mean sd inc. mean sd inc. inc. mean sd inc.

Saturna

untreated 0.6 1.6 24.0 9.4 21.3 100 0 0 0 0

CIPC 0.4 1.5 12.0 7.4 16.4 60.0 0 2.4 2.9 60.0

caraway 0.1 0.3 8.0 10.2 21.2 68.0 4.0 0 0 0

spearmint 0.9 1.4 68.0 9.0 21.2 72.0 12.0 0 0 0

3-decen-2-one 0.6 0.5 56.0 7.2 12.4 64.0 0 0 0 0

Russet Burbank

untreated 13.0 17.5 96.0 23.2 22.1 96.0 0 0 0 0

CIPC 3.2 4.0 84.0 4.0 8.5 64.0 0 7.4 8.3 100

caraway 1.0 1.7 52.0 25.0 25.8 100 0 0 0 0

spearmint 1.6 3.7 52.0 28.5 27.7 96.0 0 0 0 0

3-decen-2-one 10.6 11.7 100 20.5 24.0 96.0 0 0 0 0

4.2 Large scale (semi-commercial) experiments Season 2011-12 No sprouting was detected on either crop at intake. At 12 weeks, 99% of Russet Burbank was sprouting and then completely by 24 weeks. All Saturna were sprouting by week 12 (Table 12).

Table 12: Incidence (%) of sprouting under caraway oil 2011-12

placement Russet Burbank Saturna

12 weeks sd 24 weeks sd 12 weeks sd 24 weeks (sd) front 100 (0) 100 (0) 100 (0) 100 (0) back 98.0 (2.3) 100 (0) 100 (0) 100 (0) left 98.0 (2.3) 100 (0) 100 (0) 100 (0) right 100 (0) 100 (0) 100 (0) 100 (0) top 100 (0) 100 (0) 100 (0) 100 (0) upper middle 98.0 (2.8) 100 (0) 100 (0) 100 (0) lower middle 100 (0) 100 (0) 100 (0) 100 (0) bottom 98.0 (2.8) 100 (0) 100 (0) 100 (0) grand mean 99.0 (1.9) 100 (0) 100 (0) 100 (0)

The mean length of the longest sprout (Table 13) for Russet Burbank at 12 weeks

was 1.4 mm increasing to 32.8 by week 24. There were no differences in length due

to placement within store except that, on the second sampling occasion, it was

inhibited at the top position to a commercially tolerable mean of 5.3 mm. Saturna had

a grand mean sprout length of 11.4 mm at 12 weeks and although variation was high

there was a trend for increasing sprout suppression with higher placement in the

store with only the upper and upper middle positions commercially acceptable.

Table 13: Mean length of longest sprout (mm) under caraway oil 2011-12.


12 weeks (sd) 24 weeks (sd) 12 weeks (sd) 24 weeks (sd) front 1.4 (0.7) 28.8 (45.8) 11.8 (10.1) 89.0 (59.0) back 1.5 (1.1) 36.9 (54.8) 11.0 (9.1) 66.7 (45.4) left 1.4 (0.8) 29.6 (49.7) 10.3 (8.7) 86.3 (62.5) right 1.5 (1.1) 36.1 (51.4) 12.5 (10.3) 69.4 (41.7) top 1.2 (0.5) 5.3 (7.1) 4.2 (4.7) 45.1 (22.2) upper middle 1.1 (0.4) 57.4 (63.7) 9.0 (7.2) 81.9 (45.4) lower middle 2.1 (1.5) 34.9 (48.5) 14.7 (9.4) 119.3 (73.1) bottom 1.3 (0.5) 33.8 (50.2) 17.6 (10.1) 65.0 (27.5) grand mean 1.4 (0.9) 32.8 (50.5) 11.4 (9.6) 77.8 (53.7)

At 24 weeks all placements were unacceptable. The mean number of sprouting sites

(Table 14) in both cultivars was always greater on the second sampling occasion but

sample placement did not appear to have an influence.


Table 14: Mean number of sprouting sites under caraway 2011-12.



Fry quality at intake for both varieties was excellent. Russet Burbank chips scored

1.7 (1 light – 7 dark) and Saturna crisps had a very light mean Hunter L value of 61.1

with minimal defects, 1.6% by weight. By 24 weeks chip quality had deteriorated but

was still acceptable with an SBCSR score of 3.4 (equivalent to USDA class 0 or 1).

Crisp colour was intermediate but fry defect levels were very high (30.6%).

Table 15: Fry quality under caraway oil 2011-12.

sampling occasion

Russet Burbank Saturna SBCSR

chip score* (sd) % fry defects (sd) Hunter L

colour (sd)

intake 1.7 (0.7) 1.6 (2.9) 61.1 (0.7)

24 weeks 3.4 (0.6) 30.6 (7.1) 56.6 (1.0) * Linearised USDA scale, see Table 6. Table 16: Incidence of internal sprouting (%) under caraway oil 2011-12.

Russet Burbank Saturna

24 weeks (sd) 24 weeks (sd)

1.0 (1.9) 12.0 (5.2)

Due to the poor visual appearance of the extensively sprouting crop and high levels

of silver scurf and black dot the pathology and defect assessment was considered

irrelevant except for internal sprouting which was assessed. The incidence in Russet

Burbank was low at 1% and high in Saturna at 12%.

© Agriculture and Horticulture Development Board 2014

24

Season 2012-13

At intake no sprouting was detected in either cultivar. Sprouting incidence in Russet

Burbank averaged 56% at 14 weeks and sample placement made little difference

except that the boxes against the plenum chamber (back) at 48% had a lower

incidence of sprouting than the front stack at 63% (Table 17). By the second

assessment occasion incidence was up to 99.5%. In Saturna mean sprouting

incidence in week 14 at 92.5% was much higher than Russet Burbank.

Table 17: Incidence (%) of sprouting under spearmint oil 2012-13.


14 weeks (sd) 26 weeks (sd) 14 weeks (sd) 26 weeks (sd) front 63.0 (1.6) 99.0 (2.0) 95.0 (5.0) 100 (1.7) back 48.0 (1.5) 100 (1.7) 90.0 (1.3) 100 (1.9) left 52.0 (8.6) 99.0 (2.0) 89.0 (7.6) 100 (0) right 59.0 (11.0) 100 (0) 96.0 (3.3) 100 (0) top 54.0 (2.8) 100 (0) 100 (0) 100 (0) upper middle 58.0 (8.5) 100 (0) 90.0 (8.5) 100 (0) lower middle 54.0 (8.5) 98.0 (2.8) 90.0 (2.8) 100 (0) bottom 56.0 (22.6) 100 (0) 90.0 (8.5) 100 (0)

grand mean 55.5 (9.9) 99.5 (1.4) 92.5 (6.6) 100 (0) The mean length of longest sprout at week 14 was acceptable at 2.2 mm for Russet

Burbank and 3.8 for Saturna (Table 18). However, by 26 weeks both sprout lengths

of 62.2 mm and 37.9 mm respectively were unacceptable. No differences were

noticed due to sample placement.

Table 18: Mean length of longest sprout (mm) under spearmint oil 2012-13.



Table 19: Mean number of sprouting sites under spearmint oil 2012-13.



The numbers of sites of sprouting increased consistently from 14 to 26 weeks in both

cultivars but no trends were noticed due to placement.

Table 20: Fry quality under spearmint oil 2012-13.

sampling occasion

Russet Burbank Saturna

SBCSR chip score (sd) % fry

defects (sd) Hunter L (sd) intake 3.1 (0.7) 2.6 (0.3) 59.3 (1.5)

26 weeks 3.6 (0.7) 22.0 (6.7) 55.0 (0.6)

Fry quality at intake was fair for both Russet Burbank chips and Saturna crisps which

had few fry defects. After 26 weeks of storage the chips had deteriorated slightly but

remained acceptable. Crisp quality was poor with an intermediate colour (L value

55.0) and a high level of fry defects (22%).

Table 21: Pathology and defects under spearmint oil 2012-13.

disease or defect Russet Burbank Saturna

26 weeks (sd) 26 weeks (sd)

silver scurf incidence 94.5 (4.8) 36.5 (19.1)

silver scurf severity 29.3 (22.7) 0.8 (1.8)

black dot incidence 79.0 (15.4) 94.5 (4.8)

black dot severity 13.5 (18.6) 14.5 (17.5)

soft rot incidence 2.0 (3.7) 0 (0)

skin damage incidence 5.0 (4.7) 0.5 (1.4)

skin damage severity 0.1 (0.4) 0.01 (0.07)

internal sprouting incidence 0 (0) 1.0 (2.8)

swollen lenticels incidence 4.0 (4.3) 9.5 (5.6)


In Russet Burbank silver scurf incidence was very high and severe with a mean of

29.3% of the surface area of a tuber covered. Black dot incidence was also high but

severity lower at 13.5%. The level of soft rotting was 2%. Skin damage does not refer

to mechanical abrasion but any blemishing that might be induced by chemical

contact. An incidence of 5% was found but the severity was low. Swollen lenticels

were noticed during assessment and additionally recorded at 4%. There was no

internal sprouting.

Saturna had comparatively much less silver scurf incidence at 36.5% and very low

severity at less than 1%. However, black dot incidence was very high and of similar

severity to Russet Burbank at 14.5%. No soft rotting was found. Skin damage

incidence was low and of very low severity. Internal sprouting was found in this

cultivar but at a low incidence of 1%. Swollen lenticels were more frequent than in

Russet Burbank at 9.5%. No skin spot, dry rot, gangrene or blackheart was detected

in either cultivar.

5 DISCUSSION

In this study, the use of relatively cool (6°C) and warm (9°C) storage conditions, in

combination with a short-dormant, vigorous growing cultivar (Saturna) and a long-

dormant, less vigorous cultivar (Russet Burbank), provided a range of sprouting

pressures for the assessment of sprout suppressants. This information was then

used to scale up experimental work to a more commercially relevant scale. Under

conditions where sprouting pressure was most limited, sprouting was successfully

controlled by most suppressant treatments, including CIPC, caraway, spearmint and

3-decen-2-one.

Data from the four seasons of small-scale trials indicate that sprout control was

generally most effective using CIPC (in these trials applied hydraulically at store

loading). It provided commercially acceptable sprout control for both cultivars at both

temperatures in all four seasons. Caraway also gave relatively effective sprout

control and performed the best of all the alternatives especially at 6°C. However,

although it performed as well as CIPC, and frequently had shorter sprout lengths,

control occasionally broke down and fell below the industry standard at 9°C by 6

months. Spearmint performed adequately on both 6 °C crops, inconsistently on

Russet Burbank at 9 °C and poorly on Saturna at the warmer temperature.

Where 3-decen-2-one was used it performed well on both cultivars at 6 °C to full

term, but only consistently up to the first sampling occasion at 9 °C. However, this

chemical was applied as determined by a sprouting incidence of 75% (not length)

and the final assessment may have fallen out of step with the application programme.

In the 2011-12 season, 3-decen-2-one was used for the first time in the small-scale

trial. With this compound, a difference in the number of applications due to storage

temperature was notable.

Clove oil did not work when applied in the same way as the above alternatives,

perhaps due to lower volatility, but cannot be discounted without testing a more

appropriate method of delivery. Clove oil is registered and in commercial use in the

USA. The UV-C irradiation treatment did not differ from the untreated control where

tested.

On the basis of small-scale experimental work, caraway oil and spearmint oil

treatments were selected for use in the large-scale (16 tonnes) studies in 2011-12

and 2012-13, respectively. Caraway oil was used with the store ventilation system in

a non-positive (overhead throw) arrangement while for spearmint oil positive

ventilation was used.

Cold misted caraway oil delivered in an overhead throw ventilation system resulted in

overall poor sprout control. Control was initially good in Russet Burbank (12 weeks)

but thereafter there was only acceptable efficacy evident in top boxes. With cv

Saturna acceptable efficacy was only evident in top boxes at 12 weeks. Poor efficacy

elsewhere in the store indicates limited transport of the sprout suppressant to the

crop. With the overhead-throw ventilation principle, air (and any treatments applied

using air) is not delivered to the crop, but through the pallet apertures of boxes, with

the delivery to crop being effected by convection currents. This limits the

effectiveness of such stores for drying and chemical applications (Potato Council

Store Managers’ Guide, 2008). Results from the first large scale trial suggest that

simply using a sprout suppressant with high volatility will not sufficiently overcome

the limitations of overhead-throw store design. The likely availability of caraway oil

(Talent) for commercial use on ware potatoes in the United Kingdom is currently

unclear.

Large scale storage using spearmint oil delivered using positive ventilation at 9°C did

not control sprouting well. Although sprout control of both cultivars was initially

effective (14 weeks) it fell below commercially acceptable standards between 14 and

26 weeks. Sprouting was consistent between placements suggesting that distribution

was even, but at this temperature, for these varieties, using the standard dose rate

and application timings, control was not adequate in this store.

Processing quality in both large scale experiments were generally acceptable except

for an excessive% weight of defective crisps in Saturna.

Processing quality in Saturna crisps after full term storage were generally spoilt by

high levels of frying defects except in year 4 (season 2013-14, 9 °C). The only

treatment to stand out from the rest was spearmint in year 1 at 9 °C with few defects

and lighter fry colour, although, unusually, no defects were seen in year 4 with CIPC

or untreated tubers (both having light fry colours). Russet Burbank chips had

generally consistent fry colours between suppressant treatments, except in year 2 at

9 °C where caraway and 3-decen-2-one had better fry colour than the other chips.

The high humidity in the small scale chambers were likely to have promoted storage

diseases. Incidences of silver scurf and black dot in particular were generally very

high throughout, as might be expected at warm storage temperatures. Despite this,

no consistent effect due to sprout suppressants emerged, though a low severity of

silver scurf was seen on a number of occasions using caraway oil.

Internal sprouting occurred sporadically in most treatments, including untreated crop,

however 9 °C Saturna consistently had a high incidence, 6 °C Saturna and 9 °C

Russet Burbank showed some, whereas 6 °C Russet Burbank, with the lowest

sprouting pressure had none. CIPC generally showed much less or none of the

defect, but it was observed following caraway oil, spearmint oil, clove oil and

occasionally 3-decen-2-one.

Phytotoxicologial skin damage resembling a chemical scorch was noticed in the

study as a sporadic ‘background noise’, such that it even occurred in untreated

crops, probably confounded by a generally poor skin finish. However, CIPC was

much more likely to be associated with the defect than the other suppressants and in

2013-14 the 9°C Russet Burbank had an incidence of 100% compared with nil in all

other treatments. This is not usually a problem where CIPC is fogged but the

hydraulically sprayed liquid formulation used in this study wets the tuber skin and

delivers the dose directly. However, this might not be a problem in processing crops

where skin is peeled and skin appearance is less commercially relevant. In certain

circumstances the accurate distribution of CIPC throughout the stored crop might

outweigh the risks of partially scorched skin.

6 CONCLUSIONS

A range of alternative sprout suppressants were assessed, under standardised

conditions, in comparison with CIPC applied as a liquid, directly to tubers. Varieties

(cvs Russet Burbank and Saturna) and storage temperatures (6°C and 9°C) were

selected to give a wide range of sprouting pressure. CIPC, caraway oil and spearmint

oil resulted in effective sprout control at 6°C, consistently over three years of study.

But at a 9°C storage temperature, successful sprout control was influenced by

cultivar, season and storage duration. CIPC was the only active substance to give

consistently acceptable levels of sprouting in both cultivars, in all three seasons and

for the full storage term.

Assessment at 9°C of caraway oil on a semi-commercial scale (16 tonnes) using

non-positive overhead throw ventilation, and spearmint oil (using positive ventilation)

indicate neither of these sprout suppressants were sufficiently effective under the

conditions tested.

Although caraway oil and spearmint oil were the most promising alternative sprout

suppressants from 3 years’ small-scale work, results suggest their use in commercial

box stores (typically overhead-throw type stores in GB), or even in box stores which

have been modified to improve ventilation efficiency, would not result in sufficiently

effective sprout control. In the most demanding storage situations (e.g. late season

processing varieties with short dormancy requiring a relatively warm storage

temperature for long durations), such treatments are only likely to be of

supplementary use, i.e. replacing some CIPC treatments, not replacing all CIPC

treatments.

7 APPENDICES

7.1 Additional sprouting data Table 22: Number of sites and incidence of sprouting for Saturna.


year 1 year 2 year 3-4 sites sd inc. sites sd inc. sites sd inc.

6 °C

1

untreated 7.4 1.9 100 6.3 1.7 100 0 0.2 2.5

CIPC 2.1 2.1 76.0 4.8 2.1 95.0 0 0.2 2.5

caraway 0.7 1.8 20.0 0.7 1.2 35.0 0.1 0.2 5.0

spearmint 4.2 2.9 100 4.6 1.7 97.5 0 0 0

clove 8.0 2.1 100 3-decen-2-one 1.0 1.6 45.0 0 0 0

UV-C 0 0 0

2

untreated 7.5 1.7 100 7.2 1.8 100 6.3 2.2 100

CIPC 4.8 2.5 100 7.8 2.4 100 0.3 0.7 15.8

caraway 5.2 2.8 96.0 2.0 2.3 52.5 0.3 1.2 7.5

spearmint 6.1 2.0 100 7.1 2.9 100 3.2 2.3 90.0

clove 6.8 2.0 100 3-decen-2-one 5.4 2.4 100 0.3 0.5 20.0

UV-C 5.3 2.1 100

9 °C

1

untreated 8.3 1.5 100 6.5 1.5 100 4.0 2.0 100

CIPC 7.2 2.5 100 6.8 1.7 100 6.1 2.3 100

caraway 1.8 2.6 52.0 6.6 2.4 100 6.1 2.5 97.5

spearmint 6.3 1.8 100 6.6 1.8 100 6.3 3.6 100

clove 7.5 1.2 100 3-decen-2-one 0.8 1.1 52.5 0.2 0.4 17.5

2

untreated 7.0 1.9 100 7.2 2.2 100 4.3 1.7 100

CIPC 6.4 1.6 100 8.1 2.8 100 7.1 3.5 100

caraway 6.9 1.8 100 5.8 2.6 97.5 6.1 2.3 97.3

spearmint 4.3 1.7 96.0 6.3 2.4 100 5.2 1.8 100

clove 5.7 1.8 100 3-decen-2-one 2.1 1.3 90.0 2.8 2.0 77.5

Table 23: Number of sites and incidence of sprouting for Russet Burbank


year 1 year 2 year 3-4 sites sd inc sites sd inc sites sd inc

6 °C

1

untreated 10.1 3.2 100 2.8 3.5 45.0 0.2 1.3 2.5

CIPC 2.2 2.4 60.0 1.0 2.1 22.5 0 0 0

caraway 0 0 0 0 0 0 0 0.2 2.5

spearmint 3.6 3.8 64.0 1.1 2.7 17.5 0.4 1.4 7.5

clove 8.3 4.1 100 3-decen-2-one 0 0 0 0 0 0

UV-C 0.2 1.1 5.0

2

untreated 13.0 2.8 100 8.7 2.4 100 5.0 3.6 77.5

CIPC 8.0 2.8 100 4.8 2.5 95.0 1.1 1.7 32.5

caraway 9.4 3.8 96.0 4.1 2.3 92.5 4.4 3.5 76.9

spearmint 14.2 2.5 100 4.5 2.9 97.5 4.4 3.0 82.5

clove 11.8 3.2 100 3-decen-2-one 1.7 1.9 57.5 0.9 1.6 25.0

UV-C 5.6 3.8 90.0

9 °C

1

untreated 13.4 4.0 100 8.1 3.2 97.5 2.7 2.0 92.5

CIPC 13.3 4.4 100 4.5 3.7 72.5 1.1 2.0 37.5

caraway 0.7 1.3 32.0 3.3 4.0 47.5 5.4 3.2 97.3

spearmint 11.5 2.6 100 9.5 2.9 100 4.5 2.8 95.0

clove 11.6 3.3 100 3-decen-2-one 0.9 1.8 30.0 0 0 0

2

untreated 13.7 3.8 100 3.7 2.1 95.0 4.9 2.0 100

CIPC 12.5 3.7 100 6.6 2.5 100 11.4 3.2 95.0

caraway 13.9 2.7 100 5.4 2.7 95.0 9.6 3.4 100

spearmint 10.0 2.4 100 9.9 2.7 100 6.3 2.4 100

clove 10.4 3.2 100 3-decen-2-one 1.5 1.4 62.5 2.6 1.9 82.5

7.2 Records of application to small scale chambers 2010-11

Applicator - Badger airbrush at pressure of 0.75 bar (needle bent pointing at 1.0)All white box containers have 40 kg of potatoesVentillation halted for a target of 24 hours after each application

Date Product Batch Opened Active Volume (ml) M&TE Time Room Box number Temperature Operator16/12/2010 Biox M 10284 10/11/2010 spearmint oil 3.6 VM014 17:30 10 8 6 C GPS16/12/2010 Biox M 10284 10/11/2010 spearmint oil 3.6 VM014 17:30 11 4 9 C GPS16/12/2010 Biox C 10270 16/12/2010 clove oil 1.92 VM014 17:30 10 5 6 C GPS16/12/2010 Biox C 10270 16/12/2010 clove oil 1.92 VM014 17:30 11 1 9 C GPS16/12/2010 Talent 238060-7 16/12/2010 carvone 1.2 VM014 17:30 10 7 6 C GPS16/12/2010 Talent 238060-7 16/12/2010 carvone 1.2 VM014 17:30 11 3 9 C GPS23/12/2010 Talent 238060-7 16/12/2010 carvone 1 VM015 14:00 10 7 6 C GPS23/12/2010 Talent 238060-7 16/12/2010 carvone 1 VM015 14:00 11 3 9 C GPS30/12/2010 Talent 238060-7 16/12/2010 carvone 1 VM015 N/R 10 7 6 C GH30/12/2010 Talent 238060-7 16/12/2010 carvone 1 VM015 N/R 11 3 9 C GH06/01/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 18:00 10 8 6 C GPS06/01/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 18:00 11 4 9 C GPS06/01/2011 Talent 238060-7 16/12/2010 carvone 0.8 VM015 18:00 10 7 6 C GPS06/01/2011 Talent 238060-7 16/12/2010 carvone 0.8 VM015 18:00 11 3 9 C GPS06/01/2011 Biox C 10270 16/12/2010 clove oil 1.92 VM014 18:00 10 5 6 C GPS06/01/2011 Biox C 10270 16/12/2010 clove oil 1.92 VM014 18:00 11 1 9 C GPS13/01/2011 Talent 238060-7 40528 carvone 0.8 VM015 17:30 10 7 6 C GPS13/01/2011 Talent 238060-7 40528 carvone 0.8 VM015 17:30 11 3 9 C GPS21/01/2011 Talent 238060-7 40528 carvone 0.6 VM015 14:45 10 7 6 C GPS21/01/2011 Talent 238060-7 40528 carvone 0.6 VM015 14:45 11 3 9 C GPS28/01/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 18:00 10 8 6 C GPS28/01/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 18:00 11 4 9 C GPS28/01/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 18:00 10 7 6 C GPS28/01/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 18:00 11 3 9 C GPS28/01/2011 Biox C 10270 16/12/2010 clove oil 3.4 VM014 18:00 10 5 6 C GPS28/01/2011 Biox C 10270 16/12/2010 clove oil 3.4 VM014 18:00 11 1 9 C GPS04/02/2011 Talent 238060-7 40528 carvone 0.6 VM015 12:15 10 7 6 C GPS04/02/2011 Talent 238060-7 40528 carvone 0.6 VM015 12:15 11 3 9 C GPS11/02/2011 Talent 238060-7 40528 carvone 0.6 VM015 17:35 10 7 6 C GPS11/02/2011 Talent 238060-7 40528 carvone 0.6 VM015 17:35 11 3 9 C GPS18/02/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 17:35 10 8 6 C GPS18/02/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 17:35 11 4 9 C GPS18/02/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:35 10 7 6 C GPS18/02/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:35 11 3 9 C GPS26/02/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 12:30 10 7 6 C GPS26/02/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 12:30 11 3 9 C GPS07/03/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 14:45 10 7 6 C GPS07/03/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 14:45 11 3 9 C GPS15/03/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 17:25 10 8 6 C GPS15/03/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 17:25 11 4 9 C GPS15/03/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:25 10 7 6 C GPS15/03/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:25 11 3 9 C GPS16/03/2011 Biox C 10270 16/12/2010 clove oil 3.4 VM014 13:10 10 5 6 C GPS16/03/2011 Biox C 10270 16/12/2010 clove oil 3.4 VM014 13:10 11 1 9 C GPS22/03/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:25 10 7 6 C GPS22/03/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:25 11 3 9 C GPS30/03/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 N/R 10 7 6 C GH30/03/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 N/R 11 3 9 C GH06/04/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 11:15 10 8 6 C GPS06/04/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 11:15 11 4 9 C GPS06/04/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 11:15 10 7 6 C GPS06/04/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 11:15 11 3 9 C GPS13/04/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:40 10 7 6 C GPS13/04/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:40 11 3 9 C GPS20/04/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 10:45 10 7 6 C GPS20/04/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 10:45 11 3 9 C GPS27/04/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 18:00 10 8 6 C GPS27/04/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 18:00 11 4 9 C GPS27/04/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 18:00 10 7 6 C GPS27/04/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 18:00 11 3 9 C GPS04/05/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:30 10 7 6 C GPS04/05/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:30 11 3 9 C GPS11/05/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:30 10 7 6 C GPS11/05/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:30 11 3 9 C GPS18/05/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 17:45 10 8 6 C GPS18/05/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 17:45 11 4 9 C GPS18/05/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:45 10 7 6 C GPS18/05/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 17:45 11 3 9 C GPS25/05/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 15:15 10 7 6 C AJ25/05/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 15:15 11 3 9 C AJ01/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 16:45 10 7 6 C GPS01/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 16:45 11 3 9 C GPS08/06/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 10:25 10 8 6 C GPS08/06/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 10:25 11 4 9 C GPS08/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 10:25 10 7 6 C GPS08/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 10:25 11 3 9 C GPS15/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM027 11:15 10 7 6 C GPS15/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM027 11:15 11 3 9 C GPS22/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM027 12:40 10 7 6 C GPS22/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM027 12:40 11 3 9 C GPS29/06/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 14:15 10 8 6 C GPS29/06/2011 Biox M 10284 10/11/2010 spearmint oil 1.2 VM014 14:15 11 4 9 C GPS29/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 14:15 10 7 6 C GPS29/06/2011 Talent 238060-7 16/12/2010 carvone 0.6 VM015 14:15 11 3 9 C GPS


2011-12

Applicator - Am-Tech airbrush at pressure of 0.75 bar (needle bent pointing at 1.0)All white box containers have 42 kg of potatoesVentillation halted for a target of 24 hours after each application

Date Product Batch Opened Active Application rate Volume (ml) M&TE Time Room Box number Temperature Operator18/11/2011 Biox M 10284 10/11/2010 spearmint oil 90 ml/tonne 3.78 VM014 17:30 10 8 6 C GPS18/11/2011 Biox M 10284 10/11/2010 spearmint oil 90 ml/tonne 3.78 VM014 17:30 11 4 9 C GPS18/11/2011 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.26 VM014 17:30 10 7 6 C GPS18/11/2011 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.26 VM014 17:30 11 3 9 C GPS25/11/2011 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.26 VM014 18:30 10 7 6 C GPS25/11/2011 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.26 VM014 18:30 11 3 9 C GPS02/12/2011 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.05 VM014 15:10 10 7 6 C GPS02/12/2011 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.05 VM014 15:10 11 3 9 C GPS09/12/2011 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.05 VM014 16:35 10 7 6 C GPS09/12/2011 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.05 VM014 16:35 11 3 9 C GPS09/12/2011 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM014 16:35 10 8 6 C GPS09/12/2011 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM014 16:35 11 4 9 C GPS09/12/2011 Smartblock HA-2010/03 17/10/2011 3-decen-2-one 115 ml/tonne 4.83 VM014 16:35 11 9 9 C GPS16/12/2011 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.84 VM027 15:45 10 7 6 C GPS16/12/2011 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.84 VM027 15:45 11 3 9 C GPS23/12/2011 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.84 VM027 12:20 10 7 6 C GH23/12/2011 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.84 VM027 12:20 11 3 9 C GH30/12/2011 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 11:20 10 8 6 C AJ30/12/2011 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 11:20 11 4 9 C AJ30/12/2011 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 11:20 10 7 6 C AJ30/12/2011 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 11:20 11 3 9 C AJ06/01/2011 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:25 10 7 6 C GPS06/01/2011 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:25 11 3 9 C GPS13/01/2011 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 18:10 10 7 6 C GPS13/01/2011 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 18:10 11 3 9 C GPS20/01/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 17:25 10 8 6 C GPS20/01/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 17:25 11 4 9 C GPS20/01/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:25 10 7 6 C GPS20/01/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:25 11 3 9 C GPS27/01/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:35 10 7 6 C GPS27/01/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:35 11 3 9 C GPS27/01/2012 Smartblock HA-2010/03 17/10/2011 3-decen-2-one 115 ml/tonne 4.83 VM014 17:35 10 10 6 C GPS27/01/2012 Smartblock HA-2010/03 17/10/2011 3-decen-2-one 115 ml/tonne 4.83 VM014 17:35 11 9 9 C GPS03/02/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:27 10 7 6 C GPS03/02/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:27 11 3 9 C GPS07/02/2012 Biox C 10270 16/12/2010 clove oil 48 ml/tonne 2.02 VM014 16:45 10 5 6 C GPS07/02/2012 Biox C 10270 16/12/2010 clove oil 48 ml/tonne 2.02 VM014 16:45 11 1 9 C GPS10/02/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 17:40 10 8 6 C GPS10/02/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 17:40 11 4 9 C GPS10/02/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:40 10 7 6 C GPS10/02/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:40 11 3 9 C GPS17/02/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:20 10 7 6 C AJ17/02/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:20 11 3 9 C AJ24/02/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:45 10 7 6 C GPS24/02/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:45 11 3 9 C GPS02/03/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 16:40 10 8 6 C GPS02/03/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 16:40 11 4 9 C GPS02/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:40 10 7 6 C GPS02/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:40 11 3 9 C GPS09/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:30 10 7 6 C GPS09/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:30 11 3 9 C GPS16/03/2012 Smartblock HA-2010/03 17/10/2011 3-decen-2-one 115 ml/tonne 4.83 VM014 17:45 11 9 9 C GPS16/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:45 10 7 6 C GPS16/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:45 11 3 9 C GPS23/03/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 17:10 10 8 6 C GPS23/03/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 17:10 11 4 9 C GPS23/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:10 10 7 6 C GPS23/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:10 11 3 9 C GPS30/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:30 10 7 6 C GPS30/03/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:30 11 3 9 C GPS30/03/2012 Biox C 10270 16/12/2010 clove oil 48 ml/tonne 2.02 VM014 17:45 10 5 6 C GPS30/03/2012 Biox C 10270 16/12/2010 clove oil 48 ml/tonne 2.02 VM014 17:55 11 1 9 C GPS05/04/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:50 10 7 6 C GPS05/04/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:50 11 3 9 C GPS13/04/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 18:00 10 8 6 C GPS13/04/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 18:00 11 4 9 C GPS13/04/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 18:00 10 7 6 C GPS13/04/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 18:00 11 3 9 C GPS20/04/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:50 10 7 6 C GPS20/04/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:50 11 3 9 C GPS27/04/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 18:20 10 7 6 C GPS27/04/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 18:20 11 3 9 C GPS04/05/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 16:50 10 8 6 C GPS04/05/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 16:50 11 4 9 C GPS04/05/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:50 10 7 6 C GPS04/05/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:50 11 3 9 C GPS11/05/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:30 10 7 6 C GPS11/05/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 17:30 11 3 9 C GPS14/05/2012 Smartblock HA-2010/03 17/10/2011 3-decen-2-one 115 ml/tonne 4.83 VM014 10:40 11 9 9 C GPS18/05/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:30 10 7 6 C GPS18/05/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 16:30 11 3 9 C GPS25/05/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 10:20 10 8 6 C GPS25/05/2012 Biox M 10284 10/11/2010 spearmint oil 30 ml/tonne 1.26 VM027 10:20 11 4 9 C GPS25/05/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 10:20 10 7 6 C GPS25/05/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.63 VM027 10:20 11 3 9 C GPS


2012-13

Applicator - Am-Tech airbrush at pressure of 0.75 bar (needle bent pointing at 1.0)All white box containers have 40 kg of potatoesVentillation halted for a target of 24 hours after each application

Date Product Batch Opened Active Application rate Volume (ml) M&TE Time Room Box number Temperature Operator15/11/2012 Biox M 10284 17/10/2012 spearmint oil 90 ml/tonne 3.6 VM001 17:35 11 4 9 C GPS15/11/2012 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.2 VM001 17:35 11 3 9 C GPS22/11/2012 Biox M 10284 17/10/2012 spearmint oil 90 ml/tonne 3.6 VM001 18:25 10 8 6 C GPS22/11/2012 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.2 VM001 17:40 10 7 6 C GPS22/11/2012 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.2 VM001 17:40 11 3 9 C GPS29/11/2012 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.2 VM001 16:30 10 7 6 C GPS29/11/2012 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.0 VM001 16:30 11 3 9 C GPS05/12/2012 15kJ UV-C UV-C 2.3 mW/cm2 11 minutes MM061 am 11 1 9 C GPS05/12/2012 15kJ UV-C UV-C 2.3 mW/cm2 11 minutes MM061 pm 10 5 6 C GPS06/12/2012 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 15:10 11 4 9 C GPS06/12/2012 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.0 VM027 15:10 10 7 6 C GPS06/12/2012 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.0 VM027 15:10 11 3 9 C GPS13/12/2012 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 15:15 10 8 6 C GPS13/12/2012 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.0 VM027 15:15 10 7 6 C GPS13/12/2012 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.8 VM027 15:15 11 3 9 C GPS20/12/2012 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.8 VM027 11:50 10 7 6 C GPS20/12/2012 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.8 VM027 11:50 11 3 9 C GPS27/12/2012 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 14:10 11 4 9 C GPS27/12/2012 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.8 VM027 14:25 10 7 6 C GPS27/12/2012 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 14:25 11 3 9 C GPS03/01/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 14:45 10 8 6 C GH03/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 14:30 10 7 6 C GH03/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 14:30 11 3 9 C GH10/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 16:25 10 7 6 C GPS10/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 16:25 11 3 9 C GPS17/01/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 17:50 11 4 9 C GPS17/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:50 10 7 6 C GPS17/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:50 11 3 9 C GPS24/01/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 17:00 10 8 6 C GPS24/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:00 10 7 6 C GPS24/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:00 11 3 9 C GPS31/01/2013 Smartblock HA-2010/03 17/10/2011 3-decen-2-one 115 ml/tonne 4.6 VM001 16:30 11 9 9 C GPS31/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 16:30 10 7 6 C GPS31/01/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 16:30 11 3 9 C GPS07/02/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 17:15 11 4 9 C GPS07/02/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:15 10 7 6 C GPS07/02/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:15 11 3 9 C GPS14/02/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 16:30 10 8 6 C GPS14/02/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 16:30 10 7 6 C GPS14/02/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 16:30 11 3 9 C GPS21/02/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 16:30 10 7 6 C GH21/02/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 16:30 11 3 9 C GH28/02/2002 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 17:15 11 4 9 C GPS28/02/2002 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:15 10 7 6 C GPS28/02/2002 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:15 11 3 9 C GPS07/03/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 17:10 10 8 6 C GPS07/03/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:10 10 7 6 C GPS07/03/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:10 11 3 9 C GPS14/03/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:10 10 7 6 C GPS14/03/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:10 11 3 9 C GPS21/03/2013 Smartblock HA-2010/03 17/10/2011 3-decen-2-one 115 ml/tonne 4.6 VM001 17:25 11 9 9 C GPS21/03/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 17:25 11 4 9 C GPS21/03/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:25 10 7 6 C GPS21/03/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:25 11 3 9 C GPS28/03/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 10:15 10 8 6 C GPS28/03/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 10:15 10 7 6 C GPS28/03/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 10:15 11 3 9 C GPS04/04/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:45 10 7 6 C GPS04/04/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 17:45 11 3 9 C GPS08/04/2013 Smartblock HA-2010/03 17/10/2011 3-decen-2-one 115 ml/tonne 4.6 VM001 15:25 10 6 C GPS11/04/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM001 14:00 11 4 9 C GPS11/04/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 14:00 10 7 6 C GPS11/04/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM027 14:00 11 3 9 C GPS


2013-14

Applicator - Am-Tech airbrush at pressure of 0.75 bar (needle bent pointing at 1.0)All white box containers have 40 kg of potatoesVentillation halted for a target of 24 hours after each application CER 11 9.0 C

Date Product Batch Opened Active Application rate Volume (ml) M&TE Time Chamber Operator17/10/2013 Biox M 10284 17/10/2012 spearmint oil 90 ml/tonne 3.6 VM014 18:00 4 GPS17/10/2013 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.2 VM014 18:00 3 GPS24/10/2013 Talent 238060-7 16/12/2010 carvone 30 ml/tonne 1.2 VM014 15:30 3 AJ31/10/2013 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.0 VM005 14:15 3 GPS07/11/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM014 16:30 4 GPS07/11/2013 Talent 238060-7 16/12/2010 carvone 25 ml/tonne 1.0 VM005 16:30 3 GPS14/11/2013 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.8 VM015 16:20 3 GPS21/11/2013 Talent 238060-7 16/12/2010 carvone 20 ml/tonne 0.8 VM015 15:50 3 GPS29/11/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM014 10:50 4 GPS29/11/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 10:50 3 GPS05/12/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 15:10 3 GPS12/12/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 12:00 3 GPS19/12/2013 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM014 14:10 4 GPS19/12/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 14:10 3 GPS27/12/2013 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 11:30 3 GH02/01/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 10:25 3 GPS09/01/2014 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM014 14:10 4 GPS09/01/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 14:10 3 GPS16/01/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 16:40 3 GPS17/01/2014 SmartBlock HA-2013/21 17/01/2014 3decen2one 115g/tonne 5.8 VM014 13:10 9 GPS23/01/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 17:10 3 GPS30/01/2014 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM014 17:00 4 GPS30/01/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 17:10 3 GPS06/02/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 16:20 3 DB14/02/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 11:30 3 GPS20/02/2014 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM014 16:50 4 GPS20/02/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 16:50 3 GPS27/02/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 16:30 3 GPS06/03/2014 Talent 238060-8 17/12/2010 carvone 16 ml/tonne 0.6 VM015 16:35 3 GPS13/03/2014 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM014 17:10 4 GPS13/03/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 17:10 3 GPS17/03/2014 SmartBlock HA-2013/21 17/01/2014 3decen2one 115g/tonne 5.8 VM014 16:20 9 GPS20/03/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 17:30 3 GPS27/03/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 16:30 3 GPS03/04/2014 Biox M 10284 17/10/2012 spearmint oil 30 ml/tonne 1.2 VM014 16:50 4 GPS03/04/2014 Talent 238060-7 16/12/2010 carvone 15 ml/tonne 0.6 VM015 16:50 3 GPS03/04/2014 SmartBlock HA-2013/21 17/01/2014 3decen2one 115g/tonne 5.8 VM014 16:50 9 GPS


7.3 Product labels Biox-M label


Talent label from the Netherlands


Biox C label from USA


Documents

Final Report Evaluation of alternative sprout suppressants · Spearmint oil was effective at 6°C, but sprout control was inconsistent at the warmer storage temperature. On the basis