Efficacy of certain Clerodendrum leaf crude extracts against cutworm, Spodoptera litura Fab and cotton bollworm, Helicoverpa armigera Hub

Abstract

Efficacy of certain Clerodendrum leaf crude extracts were evaluated in the laboratory against third instar larvae of Spodoptera litura and Helicoverpa armigera. Toxicity was assessed through topical application method. The extracts of C. inerme, C. viscosum and C. philippinum were found to be more effective to both the insects. Antifeedant assay was conducted through leaf disc choice tests. Crude extracts of C. inerme, C. viscosum C. Phillipinum C. splendens, and C. multiflorum exhibited strong antifeedant activity (> 50%) at a dosage of 100-mg/ 21cm2 to S. litura. However, the H. armigera showed less antifeedant activity with more feeding of extract treated leaf in all doses. The extracts of C. inerme, C. viscosum and C. Phillipinum were exhibiting both activities. Larval growth inhibition activity was evaluated through diet. C. philippinum extract was revealed strong growth inhibition to S. litura. Extract of C. serratum showed maximum (75%) growth inhibition in H. armigera. The other plants which were tested showed moderate effects towards these pests. Based on their efficacy, some of these plant extracts have potential for use as alternative crop protectants against lepidopteran pests.