Semiochemicals from Trichosanthes anguina (Cucurbitaceae) plants influence behavior in Diaphania indica

Abstract

BackgroundFirst to third instars of Diaphania indica (Saunders) (Lepidoptera: Crambidae) feed on the lower surface of leaves, while fourth and fifth instars gregariously consume leaves of Trichosanthes anguina L. After defoliating, the caterpillar also attacks flowers and fruits of the plant and finally, results in loss of crop yield. Therefore, behavioral responses of D. indica adults were investigated to volatiles from undamaged (UD), insect‐damaged (ID, plants after feeding by D. indica larvae) and jasmonic acid (JA) treated T. anguina plants.ResultsFemales showed attraction to volatiles of UD and ID plants of three T. anguina cultivars [MNSR‐1 (MNS), Baruipur Long (BAR) and Polo No. 1 (POLO)] in Y‐tube olfactometer bioassays. Females did not show significant negative responses from volatiles of JA treated plants. Females were more attracted to volatiles of ID plants than UD plants. Females showed attraction to volatiles of UD or ID plants compared to JA treated plants. Females were attracted to certain synthetic blends resembling volatiles of insect‐damaged MNS, BAR and POLO plants in olfactometer bioassays. Females could not distinguish among these three certain synthetic blends in olfactometer bioassays. A synthetic blend of 3Z‐hexen‐1‐ol, α‐pinene, hexyl acetate, benzyl alcohol and 6Z‐nonenal at mole ratios of 1.47:1.20:1:1.82:1.21 was prepared at 20 mg/mL dichloromethane and 100 μL when used as lure in funnel traps resulted in the capture of the highest number of D. indica adults in field trails.ConclusionThe earlier five‐component chemical lure could be used in traps in an integrated pest management program of the insect pest, D. indica. © 2023 Society of Chemical Industry.

The links between plant volatiles and host plant specialization of herbivores

“…Research on host specialization of insect herbivores has heavily emphasized insect physiological adaptations and non-volatile plant metabolites in the study of host specificity evolution, often overlooking the role of plant volatiles (Awmack andLeather 2002, Howe andJander 2008), despite evidence that a diverse array of volatiles is vital for insect foraging (Bruce et al 2010, Debnath et al 2023, Franco et al 2021, Kariyat et al 2012, Szendrei and Rodriguez-Saona 2010. These volatiles, pivotal for host location, have rarely been the focus.…”