Date of this Version
A bioassay employing sweetclover root disks impregnated with various plant extracts has been developed. The bioassay has been used to demonstrate the distribution of substances influencing feeding in fractionated water-methanol-chloroforrn extracts of Melilotus infesta Guss. and M. oficinalis L. Lam. leaves. Indications are that substances responsible for the resistance of M. infesta or the susceptibility of M. officinalis to feeding by adult sweetclover weevils, Sitona cylindricollis Fåhraeus, reside in the water-methanol fraction.