Effects of soybean leaf extracts on growth and mortality of bollworm (Lepidoptera: Noctuidae) larvae

Serial extracts of dried soybean, Glycine max (L.) Merrill, leaves from the insect-resistant line PI 229358 were made with solvents of increasing polarity. Extracts, singly or in combination, were incorporated in an artificial diet medium fed to bollworm, Heliothis zea (Boddie), larvae. All extracts caused increased larval mortality. Larval deaths were associated with failure to complete larval-to-pupal metamorphosis. An extract containing water-soluble compounds slowed development. Implications for host plant resistance are described.