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S. Krisna Kumar

Deciphering the chemical cues underlying the oviposition behaviour of spotted bollworm, Earias vittella Fabricius in Okra - P 185-194

Insect pests that attack plants generally exhibit a
strong preference for specific phenological stages of
their host plants for feeding and oviposition. In this
study, we examined the influence of different phenological stages volatiles of okra (Ablemoschus esculentus),
namely pre-flowering, flowering and fruiting, on the
behaviour of the notorious pest, spotted bollworm
(Earias vittella Fabricius). To understand the olfactory
response of E. vittella, we utilized a Y-tube olfactometer, gas chromatography electroantennographic detection
(GC-EAD) and gas chromatography-mass spectroscopy
(GC-MS) techniques. Among the three host plant phenological stages, the volatile cues from the fruiting
stage were significantly attractive to E. vittella. The
specific chemical cues responsible for this attraction
were identified using GC-EAD/GC-MS. The electrophysiological studies revealed a total of 14 chemical
cues that elicited a clear antennal response in the gravid
female moths of E. vittella. Further, detailed olfactometer
bioassays with synthetic compounds revealed that four
compounds elicited a significant attraction in gravid
female moths and one elicited significant repulsion response. The study provides valuable insights into the
host plant preference of E. vittella and identifies the
underlying potent attractive chemicals for its future
management strategies.

Subjects--Facted Index Terms:
Ablemoschus esculentus
fruit and shoot borer
GC-EAD/GC-MS
olfactometer assays
phenological stages
volatiles