1. Dr. N.Bakthavatsalam and Dr. Kesavan Subaharan*
Innovation in Insect Pest Management : Interventions Using Insect Responsive Volatiles
Dr. N.Bakthavatsalam and Dr. Kesavan Subaharan*
ICAR – National Bureau of Agricultural Insect Resources
Bengaluru – *

2. Introduction
Population explosion demands higher food /milk/ meat production
Increased dependency on agro inputs – Fertilizers, pesticides and antibiotics
Balance between crop/animal production and environment protection to be achieved - Eco - friendly measures
Understanding chemoecological approaches – Development of robust pest management methods

3. Chemoecological approach depends on
Long distance cues based on Chemical stimuli
- Volatile organic compound
- Olfaction
Short distance cues – Vision and gustation
Pheromone - Exchanged between individuals of the same species.
Allomone : Interspecific that benefit the originator but not the receiver.
Kairomone : Interspecific that benefit the receiver but not the emitter.
Synomone : Interspecific that benefits both parties.

4. Centre of insect olfaction – Antenna – Signal transducer
Sensilla morphology of female Manduca sexta
Leading surface view of female flagellar annullus
Sheilds et al., 2001
Manduca sexta
Trichoid A type
Basiconic A type

5. Antennal morphology exhibits sexual dimorphism
Female
Male

7. Perireceptor events - Olfactory transduction pathway
Olfactory receptor neurons
Responds to chemical stimuli
Translates it to brain language
– electrical signals

8. Assessing the sensory physiological response to chemical stimuli
Electroantennogram - summated response of neurons to VOC Aids to identify the peripheral response of antennae to stimuli (Attractant / Repellent) Rapid technique for screening stimuli Not a stand alone technique to identify an attractant
EAG – Automated odor delivery system

9. Simultaneous biological and chemical detection
GC – EAD Simultaneous biological and chemical detection to pinpoint the VOC causing physiological response
Reinjection of sample into GC MS may lead to shift in retention time – Misidentity of compounds
Combining GC + FID + EAD + MS robust method for simultaneous biological detection and chemical identity
GC EAD 1 2 3 4 5 6 7 8 9
GC + FID + MS + EAD
GC EAD response of female Manduca sexta to Datura wrightii
1 = cis 3 hexenol 3 = cis 3 hexenyl acetate 5 = cis alpha ocimene 7 = Methyl salycylate 9 = Squalene
2 = Benzaldehyde 4 = benzyl alcohol 6 = Methyl benzoate 8 = alpha farnesene

10. Olfactory basis of host selection by Manduca sexta

11. GC - Single Cell Recording – Manduca sexta female
GC – SSR unit
Prep. mounting
GC SSR trace

12. GC SSR traces of M. sexta ORN to Nicotiana attenuate volatiles1 2
1 = cis 3 hexenol
2 = cis 3 hexenyl acetate
3 = Benzyl alcohol
4 = Methyl benzoate
5 = Decanal 3 4 5
Cell 1
Cell 2
Cell 3

13. Response of sensilla to stimulus class
Fisher,s exact test, p <0.0001

14. Adult M.sexta response to larva frass – Oviposition deterrent
Hexanoic acid
Butanoic acid

15. Oviposition choice assay

16. Oviposition preference choice by Manduca sexta
G test p = 0.05

17. Frequent need to service trap – technology adoption low
Pheromone Kairomone synergists for trapping Red palm weevil, Rhynchophorus ferrugineus
Concealed nature of red weevil, Rhynchophorus ferrugineus is a hurdle in its management.
Insecticides (Chloranthriniprole and imidacloprid) are an effective pest management tool, but the ill effects on consumers and environment is a concern.
Using food baits with aggregation pheromone synergized trapping efficiency(CPCRI, 2003; Rochat and Avand Fagigh, 2000).
Frequent need to service trap – technology adoption low
Red palm weevil
Pheromone trap with food

18. Gaps identified
Commercially available dispensers have high release rate. This warrants frequent replacement of the lures at 2 – 3 months interval which increases the cost towards labor and lure.
Frequent replacement of polymer membrane or polypropylene dispensers leads to accumulation in agricultural fields causing environmental pollution.
Hypothesis
Nanoporous materials are a novel dispensers for volatile signaling molecules. The nanoporous materials when used as pheromone delivery system tends to have a controlled spatiotemporal release rate that aids to enhance the longevity of lures

19. Multi location trial to assess the performance of lure loaded in nanomatrix
Weevils capture / trap (mean + SE)
Χ2 = df p= Χ2 = df p= Χ2 = df p=0.01
Kruskal Wallis test

20. Assessing the field efficacy of pheromone + Kairomone blend in trapping red palm weevil (Vepankulam, Tamilnadu
Mean followed by same letter in a column do not differ significantly by DnMRT (p=0.05)

21. The South American Tomato Leaf miner (Tuta absoluta)
Invasive pest Brazil – Europe – Middle East – India.
Alien invasive into India during 2014

22. Field demonstration of Tuta pheromone

23. Cashew stem and root borer, P. ferrugineus
1-hexadecanol as probable male aggregation pheromone

24. Banana pseudostem weevil, Odoiporus longicollis
Plant volatiles from susceptible Nendran cultivar of banana indicated the presence of Heptanoic acid and Pentanoic acid as probable attractants

25. Coffee stem borer, Xylotrechus quadripes
α-pinene from ‘arabica’ coffee has been found to be attractant

26. EAG response of Male (Guntur) population to pheromone blends
Air
Honey
Z 11
Z-9
85:15
88:12 2
91:9
94:6
97:3
honey

27. Chemoecological approaches in veterinary entomology House fly, Musca domestica
M. domestica – a cosmopolitan fly - abundant in places where livestock, poultry and companion animals are housed.
Presence cause annoyance in animals
House fly larvae cause secondary wound myiasis
Control – Imidacloprid, Fipronil
M. domestica

28. Chemoecological methods in biological control Olfactory learning in G
Chemoecological methods in biological control Olfactory learning in G. nephantidis
Infested palms by O. arenosella takes fours years to regain normal yield potential (Chandrika Mohan et al., 2010).
Varying degree of success reported due to release of these parasitoids.
Chemical cues from damaged plant and host mediate the attraction of parasitoids (Vet et al., 1995).
Olfactory conditioning of parasitoids to host cues would facilitate their learning to identify their host even if they were reared on alternate lab hosts.
O. arenosella larvae
Infested garden
Goniozus nephantidis

29. EAG antennal response to host products
The bar in Grey represents female and Dark Red represents male.

30. Olfactory conditioning of parasitoids with host products
Conditioning with volatiles from larval frass Learning assessed in Y tube assay.
Olfactory learning in G. nephantidis

31. Situation Today and in the Future
Market for pheromone-based control products is about $200 million world-wide currently but growing at over 10% per annum
780,000 ha treated in 2015 with pheromone-based products
It is still under 3% of the world-wide Insecticide Market ($9 Billion)
Greater scope exists for repellents, arrestants, alarm pheromones.
Identifying host volatiles will aid to synergise pheromone trapping
Controlled Release - an area of issue in semiochemical industry

32. Acknowledgements ICAR, New Delhi Department of Biotechnology
Tata Institute of Fundamental Research
Max Planck Society, Germany
Swedish Lund University

33. Thank you