aBuckeye Valley High School, 901 Coover Road, Delaware, Ohio 43015
We tested chemical and insect feeding-induced insect resistance on soybean plants. The chemical induction effects of jasmonic acid (JA) and salicylic acid (SA) were investigated. We also evaluated the effects of plants stressed with previous insect herbivory. A larval antibiosis screening technique (LAST) and a preference test were performed in petri dishes using Mexican bean beetles, Epilachna varivestis Mulsant, to monitor the effects of resistance in soybeans. Results from the LAST assessment showed evidence of both chemical and insect feeding induction of resistance. JA applied to the plant resulted in greater insect mortality and less larval damage than did the controls, indicating an increased resistance to herbivorous stress. In contrast, plants treated with SA had slightly less resistance. In the previously insect-damaged study, plants that had portions of lower leaves consumed by the beetle developed a higher level of resistance to subsequent feeding of the upper leaves. Preference studies were inconclusive because of a general lack of insect feeding. Induced resistance could provide a means to enhance the natural resistance of soybeans to pests, benefiting both consumers and producers.