Systemically released volatiles from Solena amplexicaulis plant leaves with color cues influencing attraction of a generalist insect herbivore

Solena amplexicaulis (Lam.) Gandhi (Cucurbitaceae) is a promising vegetable in Southeast Asia. Infestation of Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae) adults on leaves of the crop plant causes death of the plant and reduces crop production. Currently, growers are applying insecticides to control this pest, which are harmful to health and environment. Hence, an attempt has been made to find out allelochemicals from leaves attracting the insect, which might be used for ecofriendly pest management program. The emission of volatiles was detected from undamaged leaves of herbivore-induced plants after 24 h and 120 h of continuous females feeding on lower leaves of the same plants by GC-MS and GC-FID analysis. The insect showed attraction to systemically released volatiles from herbivore-induced plants against unharmed plants in Y-shaped glass tube olfactometer bioassays. The insect was attracted to a synthetic blend of 1.2 µg linalool oxide + 3.2 µg nonanal + 1.5 µg trans-2-nonenal dissolved in 20 µL CH₂Cl₂ in olfactometer and wind tunnel bioassays, and hence, this blend could be used in development of baited traps in pest management strategies.