ALFALFA LEAF SAPONINS AND INSECT RESISTANCE

Dried alfalfa (Medicago sativa) leaf tissue incorporated in artificial diet to give a final concentration of 0.5 or 1.6 mg/g fresh weight of saponins significantly inhibited growth and development of larvae of the European corn borer (Ostrinia nubilalis). Saponin fractions isolat ed from root or shoot tissues of alfalfa also inhibited growth when in corporated at equivalent concentrations but had little effect on devel opment. Root saponins were somewhat more harmful than shoot saponins.