Effects of Five Insecticides on the Probing, Walking, and Settling Behavior of the Green Peach Aphid and the Buckthorn Aphid (Homoptera: Aphididae) on Potato

Abstract

From 14 to 26% of apterous green peach aphids, Myzus persicae (Sulzer), placed on leaflets of potato treated with deltamethrin, fenvalerate, pirimicarb, and methamidophos dispersed to untreated leaflets, compared with only 2-6% of aphids placed on control or dimethoate-treated leaflets. Apterous buckthorn aphids, Aphis nasturtii (Kaltenbach), dispersed significantly in greater numbers only from deltamethrin and fenvalerate treatments. Pyrethroids reduced duration of probing for alate and apterous morphs of both species from 33 to 77%. Dimethoate decreased probing of apterous A. nasturtii 24%, while methamidophos did not alter probing times for apterous or alate morphs of either species. Pirimicarb reduced probing times of M. persicae , and the results indicated that the effect on probing may depend on the condition of the leaf material or species of aphid. Colonization of pyrethroid-treated and untreated leaf disks in flight tests suggests no repellent action on M. persicae . Decreased probing on pyrethroid-treated leaves could help control the spread of nonpersistent viruses, but increased dispersal of aphids might decrease the effectiveness of control. These data extend the behavior-modifying properties of pyrethroids to A. nasturtii and confirm that nonpyrethroid insecticides can affect the behavior of certain aphid species.