Effects of isoflavonoids from Cicer on larvae of Heliocoverpa armigera.

Abstract

Four recently identified isoflavonoids, isolated from wild relatives of chickpea, Cicer arietinum, were shown to deter larval feeding by Heliocoverpa armigera at 100 ppm, judaicin and maackiain retained their antifeedant activity at 50 ppm and 10 ppm, respectively. The isoflavonoids were tested in combinations and with chlorogenic acid; the combinations containing judaicin and maackiain were most active, and chlorogenic acid enhanced the antifeedant activity of all four isoflavonoids. H. armigera was the only one of four noctuids to be deterred by all four isoflavonoids. Spodoptera littoralis was deterred by judaicin alone and S. frugiperda by maackiain alone. Heliothis virescens and S. exigua were not deterred from feeding by any of the isoflavonoids. When incorporated into a diet, isoflavonoids decreased the weight gain of early stadia larvae of H. armigera more than they did later stadia, and maackiain and judaicin were most potent. We conclude that the isoflavonoids. especially maackiain and judaicin, could play a role in decreasing the susceptibility of Cicer to attack by H. armigera.