Feeding deterrency of some 4-hydroxycoumarins and related compounds: Relationship to host-plant resistance of alfalfa towards pea aphid (Acyrthosiphon pisum)

Abstract
A series of 3-acyl-4-hydroxycoumarins, structurally related to dicoumarol, as well as several alfalfa constituents including coumestrol were tested for their feeding deterrency towards the pea aphid. Feeding deterrency of the 3-acyl-4-hydroxycoumarins decreased as the size of the 3-acyl group increased.