Foxglove Aphids in Lettuce: Control with Reduced-Risk and Conventional Insecticides

Abstract

Several small-plot studies were conducted in the spring of 2003 to compare the residual efficacy of several new reduced risk insecticides with a number of conventional aphicide compounds on head lettuce and romaine. Our efforts were primarily directed at determining efficacy against the foxglove aphid, a newly discovered pest in Yuma. In general, several new neonicotinoid foliar compounds provided good residual control of all aphid species including foxglove aphid. Other new compounds were less consistent. Admire, the standard soil systemic used in lettuce, was inconsistent against Foxglove aphid providing 85-90% control relative to >95% control against other aphid species present in the plots. Conventional aphid compound such as Capture, dimethoate, endosulfan, Orthene and MSR consistently provided good, economic control of Foxglove aphids in both head and romaine lettuce. Based on the results of these and previous studies, a sampling procedure and action threshold are recommended for foxglove aphid control in desert lettuce.