Green Solutions for Agriculture: Feeding and Oviposition Responses of Plutella xylostella (L., 1758) to Botanical Extracts Under Free-Choice and No-Choice Conditions

Botanical insecticides have emerged as promising tools for sustainable pest management due to their multifunctional activity, including behavioral effects. In Part I of this investigation, the topical and oral toxicity of aqueous leaf extracts from Tapirira guianensis, Coussarea hydrangeifolia, Duguetia furfuracea, and Anemopaegma arvense against Plutella xylostella was demonstrated. However, the effects of these extracts on the feeding behavior and oviposition of the insect remained unknown. Therefore, this study evaluated the feeding and oviposition responses of P. xylostella in both free-choice and no-choice assays to better understand the ecological relevance of these extracts against an economically important pest. All extracts exhibited feeding deterrence in the free-choice assays. Under no-choice confinement, larval consumption was higher for D. furfuracea and A. arvense, although this contrast was not statistically confirmed. In contrast, T. guianensis and C. hydrangeifolia consistently reduced larval consumption regardless of the experimental context. Regarding oviposition, all extracts acted as oviposition deterrents in the free-choice assays. Under no-choice conditions, distinct behavioral responses were observed. T. guianensis stood out by combining oviposition deterrence with consistent feeding suppression, showing the most consistent evidence of activity among the four extracts. The integration of these findings with previously obtained toxicity data suggests that these extracts exert multiple biological effects, including behavioral modulation and direct toxicity, although the underlying modes of action were not identified. These combined effects may enhance their potential for use in Integrated Pest Management (IPM) programs. Furthermore, the differences observed between free-choice and no-choice assays highlight the importance of integrated experimental approaches for evaluating botanical insecticides, although field or semi-field validation will be required to confirm these effects under crop conditions.