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 – 560024 *Email : subaharan_70@yahoo.com

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

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.

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

Antennal morphology exhibits sexual dimorphism Female Male

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

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

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

Olfactory basis of host selection by Manduca sexta

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

GC SSR traces of M. sexta ORN to Nicotiana attenuate volatiles 1 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

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

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

Oviposition choice assay

Oviposition preference choice by Manduca sexta G test p = 0.05

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

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

Multi location trial to assess the performance of lure loaded in nanomatrix Weevils capture / trap (mean + SE) Χ2 = 11.93 2 df p=0.01 Χ2 = 12.93 2 df p=0.01 Χ2 = 12.98 2 df p=0.01 Kruskal Wallis test

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)

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

Field demonstration of Tuta pheromone

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

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

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

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

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

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

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

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

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

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

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