Evaluation of Biopesticide Efficacy Against Insect Pest Complexes in Open-Field Tomato (Solanum lycopersicum) Production in Ogun State

The increasing development of insecticide resistance among key tomato insect pests, including Helicoverpa armigera, Bemisia tabaci, and Thrips tabaci, is undermining the efficacy of conventional chemical pest management in South West Nigeria. Biopesticides derived from botanical, microbial, and entomopathogenic sources offer a promising component of integrated pest management strategies. This study evaluates the efficacy of four commercially available biopesticide formulations, neem seed kernel extract, Bacillus thuringiensis-based formulation, spinosad, and pyrethrin, against the dominant insect pest complex in open-field tomato production in Sagamu, Ogun State. A field experiment using a randomized complete block design with five treatments including a synthetic insecticide standard and an untreated control was conducted over two cropping seasons. Pest population counts, percentage leaf damage, percentage fruit damage, marketable fruit yield, and cost-benefit ratio were recorded. Results indicate that spinosad and Bacillus thuringiensis-based treatments achieved pest suppression and yield protection comparable to the synthetic insecticide standard, with significantly lower residue risk. Neem extract showed moderate efficacy but required more frequent application. The study recommends spinosad as the primary biopesticide for commercial tomato pest management in Ogun State. Keywords: biopesticides, tomato, insect pest management, Ogun State, integrated pest management