Welcome“Role of pheromones in stored

grain pest management”

Course In-charge Dr.S Jayaraj Nelson

Department of Agri.EntomologyCPPS,TNAU.

SSNAIK

Role of pheromones in stored grain pest management

1.Introduction2.Classification of semiochemicals3.Control methods

1.INTRODUCTION

Semiochemicals: Semiochemicals are the substances or the chemicals which are useful for the establishing interactions between the two organisms.

Pheromones:Pheromones-chemicals secreted or excreted into the external environment by an animal which elicit a specific reaction in a receiving individual of the same species.

Semiochemicals that have intraspecific signals are called as pheromones

What are the semiochemicals ?

Etymology: Peter Karlson and Martin Luscher

introduced the word pheromone in1959.

Derived – Greek word. Two words :1.Pherein = to transport 2. Hormone = to stimulate

1959- German chemists Karlson & Butenandt

Pheromones:

Volatile. Low molecular weight. Organic compounds.Various structures.Ectohormones. Communication among insects of the same species.

Structural diversity of Pheromones

Insect Pheromone structure

1.Plodia interpunctella

(Z,E-9,12_tetradecadienyl acetate or ZETA)

2.Tribolium castaneum

4, S-Dimethyl decanal

3.S. zeamais

4-Methyl-5-hydroxy-3-heptanone, or ‘sitophinone

A

B

Pheromone

Allelochemical

Semioc

hemica

lEcosystem

Species A

Species B

Common pheromone producers Female-produced sex pheromones

AnobiidaeBruchidae Dermestidae

Male-produced aggregation pheromones

Bostrichidae Cucujidae CurculionidaeTenebrionidae

2. CLASSIFICATION

Classification of semiochemicals

3.CONTROL METHODS

1.Long range methods 2.Short range methods

Volatile chemicals, Insect attractants or repellents.Protect the commodity

1.Attractants and Mass trapping2.Attracts and kill methods3.Mating disruption

Involatile chemicalsStimulant or deterrent propertiesAffect -Insect reaching the commodity

1.Behavioral stimulants2. Behavioural deterrents

1.Long range methods 2.Short range methods

Methods:

Long-range control methods

Mass trapping is a logical extension of the successful use of traps for monitoring purposes.

It is necessary to place enough traps in strategic positions to remove a sufficiently high proportion of individuals from the pest population to achieve the required level of protection.

1.Attractants and mass trapping:

Laboratory-based studies on mass trapping in 1980s suggested this technique would not be effective for stored product insects because of the poor catches possibly associated either with early trap designs or the presence of contaminating isomers in the lure

(Barak and Burkholder, 1985).

Showed that the major component of the female-produced pheromone of Ephestia kuehniella Zeller had potential for use in controlling this pest in flour mills.

( Levinson and Buchelos ,1981)

Combination of mass trapping of male moths with pheromones

Thorough cleaning of mill and machinery Minimal use of insecticide appears to have been effective

in reducing population to below economic thresholds in Italian flour mills

(Trematerra, 1994)

Contd………. Control of E. kuehniella

Mass trapping of Lasioderma serricorne(F.) in Greek tobacco stores

Sex pheromone component anhydroserricornin on multi-surface sticky traps. Removed 500,000 male beetles. 15 month period. (Buchelos and Levinson, 1993)

Hawaiian food warehouses -mass trapping with pheromones Cost effective -alternative to fogging with insecticides against L. serricorne and P. interpunctella (Pierce, 1994)

Contd……….

Problems of mass trapping of insects : Presence of dead Tribolium castaneum (Herbst) in traps Act repellent Presence of residual quinones Trapped dead beetles (Trematerra et al., 1996)

To be effective, mass trapping must ensure that a high proportion of female pests are either trapped or left unmated.

Most attempts to suppress stored grain insects

using this method have relied on sex pheromones that attract only the male.

However, some species produce aggregation pheromones that attract adults of both sexes to a suitable food source

(Burkholder, 1990).

Contd……….Examples aggregation pheromones:

Insect Aggregation pheromone

T. Castaneum

S. granarius

(4R,8R)-(-)-4,8-dimethyl-decanal

1-ethylpropyl (2S,3R)-5-hydroxy-2-methylpentanoate

(Suzuki and Sugawara, 1979)

(Phillips et al.,1989; Chambers et al.,1996)

Most insect pheromones are species-specific which, for control purposes, means that a different chemical must be deployed for each pest species present. However, some cross-species attraction has been demonstrated in the pheromone components of a number of beetles commonly associated with stored grain .

(Cox and Collins, 2002)

Contd……….

The species are:Cryptolestes ferrugineus (Stephens)Cryptolestes pusillus (Sch. onherr) (Chambers et al., 1990), Sitophilus oryzae (L.), Sitophilus zeamais Motschulsky and S. granarius (Walgenbach et al., 1983; Phillips et al., 1985), Oryzaephilus surinamensis (L.),Oryzaephilus mercator (Fauvel) and Ahasverus advena (Waltl) (Pierce et al., 1991), Rhyzopertha dominica (F.) and Prostephanus truncatus (Horn) (Williams et al., 1981, Hodges et al., 1984), Trogoderma granarium Everts, Trogoderma inclusum LeConte and Trogoderma variabile Ballion (Greenblatt et al., 1977), Tribolium confusum (du Val), Tribolium freemani Hinton and T. castaneum (Suzuki et al., 1987).

Food volatiles are another source of lures some of which have the advantage of being attractive to the adults and larvae of both sexes of a wide range of species of stored grain pests.

Role of food volatiles

Food volatile Insect attracted Wheat germ 15% lipid, upto 60% of which is triglyceride. Unsaturated triglycerides are particularly attractive and elicit aggregation responses

S. granariusO. surinamensis

Pod pieces and extracts from the carob tree

O. surinamensis, S. granarius, C. ferrugineus A. advena

Role of food volatiles…….

volatiles, valeraldehyde, maltol and vanillin, and 5R,4S -sitophilure

S.oryzae

Food lures used in combination with pheromones may offer a way of enhancing the effectiveness of mass-trapping systems for stored grain pests.

Phillips et al. (1993) found that in laboratory tests a combination of three grain volatiles, valeraldehyde, maltol and vanillin, and 5R,4S -sitophilure was more attractive to the rice weevil Sitophilus oryzae than either the pheromone or the grain volatile alone

2.Attractant and kill methods

A.The method involves.. lure -attract pests -treated with an insecticide

or other control agent.

E. kuehniella in Italian flour mills:

Attracting male moths to dispensers (combination of sex pheromone and the pesticide cypermethrin ).

(Trematerra, 1994)

Contd……..

B.Control stored product pests using semiochemicals and to attract them to a source of pathogens

Attracted the dermestid beetle Trogoderma glabrum (Herbst) to a pheromone source containing the protozoan pathogen Mattesia sp., subsequently transmitting the disease to over 90% of a test population.

(Burkholder and Boush 1974)

Contd……..

Recently vegetable fat pellets containing an aggregation pheromone and the entomopathogenic fungus, Beauveria bassiana (Balsamo) Vuillemin have been used in laboratory tests to attract and kill Prostephanus truncatus

(Smith et al., 1999).

Contd……..

The method showed promise for the control of this beetle in maize stores and has the additional advantage that using the fat pellet formulation avoids any possible allergen hazard associated with the presence of airborne fungal conidia.

AdvantagesReduce the amount of toxic chemical Restricting its application to a much smaller areaReducing costs Reducing hazards by blanket pesticide treatments

Disadvantages

No further tests or field trials of this method, possibly reflecting no concerns over the use of pathogens generally.The pathogens used were too species-specific, rendering them ineffective in storage environments where a number of different pest species are often present.

Contd…

3.Mating disruption

This technique relies for its success on using pheromones to prevent mating and the subsequent laying of fertile eggs. The mechanisms involved are not completely understood (Cardle and Minks, 1995); however, the three most likely modes of action are:

(i) Adaptation of the antennal receptors and habituation of the central nervous system, caused by the continuous exposure of insects to a relatively high concentration of pheromone, which prevents the insect responding to a potential mate.

(ii) Camouflaging of the natural pheromone plume from a

calling mate resulting from the use of a high background level of pheromone which renders trail-following for real mate

(iii) False-trail following when a relatively large number of point sources of pheromone are spread around an area to present the pest with many false trails

Mode of action

Mating success and population growth rates of P. interpunctella and E. cautella, were substantially reduced in the presence of synthetic sex pheromone in simulated storages (Sower and Whitmer, 1977).

for example, that mating frequencies in E.cautella were reduced from 56% to 70%.

Contd..

Experimental trials

Controlled release system for dispensing pheromones to disrupt mating of E. cautella (Mafra-Neto and Baker, 1996)

In laboratory and in cocoa stores

Micro-encapsulated formulations of synthetic pheromone used against E. cautella .Significant mating disruption and population reduction

(Hodges et al., 1984)

F1 emergences were reduced by over 97% at population densities of 0.25 moths/m2 (Prevett et al., 1989)E. kuehniella-Italian flour mill -laminar pheromone dispensers numbers of insects caught increased.

(Trematerra and Capizzi, 1987)

1.Dermestid storage beetles Prior exposure of male sex pheromone for 2 days Resulted reduced mating efficiency (Rahalkar et al., 1972)

2. black carpet beetle, Mating was reduced -adults of the Attagenus megatoma-exposed to synthetic sex pheromone, megatomoic acid .

(Burkholder, 1973)

Laboratory tests

2.Short-range control methods

Insect movement or feeding -improve the efficacy of insecticides and bio control agents.Feeding stimulants -wheat germ, cotton seed flour and cotton seed oil -attract the insect

Bacillus thuringiensis and Nuclear polyhedrosis virus. (Navon et al., 1997)Microbial agents B. thuringiensis are registered for use on stored grain in the USA.

(Cox and Wilkin, 1998)

1.Behavioral stimulants

2. Behavioural deterrents

Chemical inhibit -oviposition or feeding.For example, mandibular glands of P.

interpunctella secrete semiochemicals which are deposited -food and silk

(Corbet, 1971)

Not prefered by larvae

Plants chemicals -antifeedant properties against stored grain pests1. the compound bis abolangelone from wild angelica, Angelica sylvestris L. (Umbelliferae), a good feeding deterrent for S. granarius, T. confusumand T. granarium-reducing oviposition (Nawrot et al.,1986)2. pentane extracts (Ovipositional and gustatory stimulants) –stored wheat -females S. granarius (Kanaujia and Levinson,1981)

Contd…….

Terpenoid, lactones, common secondary metabolites plants -exhibit antifeedant activity beetle species -T. confusumand T. granarium (Paruch et al., 2000).

use of such antifeedants :reduce damage -feeding stop insects -moving to grain bulk Avoids -laying eggs

Conclusion

As the semiochemicals are involved in the behavoural modification ,non chemical methods ,less persistance no residues on the grains ,as our concern to eatable grains it is the best method to control the pests of storage grains

Than

ks a

lot……

Presented by S.Srinivas naikId no -13-503-

010