Exploring Vegetable Ecosystem for Parasitoids of Lepidopteran Pests and Host Suitability of Predominant Parasitoid in Kerala, India

Abstract

Aims: Documentation of larval parasitoids of lepidopteran pests in vegetable crops from Kerala and finding out host suitability of predominant larval parasitoid for the purpose of mass production. Study Design:  Completely Randomized Design for laboratory experiment.                           Place and Duration of Study: College of Agriculture, Vellayani, between November 2023 and July 2024. Methodology: A periodic survey was conducted in selected agricultural fields of Kerala to collect lepidopteran pests. The collected larvae were kept in laboratory condition, to observe parasitization, highly polyphagous parasitoid obtained was designated as the predominant one. For the assessment of suitable host for the mass production the two natural hosts from the survey and Corcyra cephalonica and Galleria mellonella was reared in the laboratory condition and and assessed for preference by the predominant parasitoid. Results: Bracon hebetor Say was identified as the predominant parasitoid in the vegetable ecosystem, which was identified by experts and confirming a parasitization rate of about 61.8%. Chalcids, Cotesia and Bracon brevicornis were other parasitoids emerged. The cucumber moth and cotton leaf roller were the major hosts, exhibiting parasitization rates of 60-90%. G. mellonella was found to be the most effective host other than C. cephalonica and the natural hosts, supporting high fecundity, a short life cycle, and a substantial number of emerging parasitoids Conclusion: There is a considerable amount of natural parasitation in the vegetable ecosystem and predominantly by the braconoid parasitoid, B. hebetor. It can be successfully mass produced using G. mellonella.