Insecticidal Control of Lygus Bugs and Effect on Yield and Grade of Lima Beans1

Abstract

Excellent control of lygus bugs on lima beans was obtained for several weeks following treatment with a malathion plus toxaphene combination or with dimethoate. Malathion or naled alone also provided satisfactory lygus bug control, with shorter periods of effective residual activity than malathion plus toxaphene. Although the initial control of lygus bugs afforded by a DDT plus toxaphene combination was poorer than that given by the above treatments, this combination continued to suppress the bugs for at least 4 weeks following application. Two types of damage may be caused by the feeding of lygus bugs on lima beans in California: a reduction in yield, as measured by the number of marketable beans per plant, and pitting or scarring of the beans. Two properly timed applications of malathion plus toxaphene were found necessary to provide adequate control of both types of damage on crops to be harvested as dry limas while a single application gave adequate control of both types of damage on crops to be harvested as green limas.