Notes on and Control of Stink Bugs Affecting Cotton in Arizona1

Abstract

The brown cotton bug, Euschistus impictiventris Stal, is the dominant stink bug pest in the major cotton growing areas of central Arizona while the Say stink bug, Chlorochroa sayi Stal, dominates in cotton in higher elevations of eastern Arizona. Effective estimates of populations, to determine the need for control treatments, require that sweep net counts be augmented by counts of insects observed but not caught. Stink bugs are not caught in representative numbers with a standard net because of their rapid movement and their frequent location on the plant below the range of the normal net stroke. From 1959 to 1961 stink bugs caused shedding of newly formed bolls and, later in the season, damaged bolls remaining on the plant, causing carpel injury, seed injury, stained lint, lowered yields, lower quality, and the encouragement of boll rot fungi. Alfalfa and sugar beets were preferred over cotton by the brown cotton bug in central Arizona. Cotton was more heavily attacked when grown near alfalfa, particularly after alfalfa was cut or permitted to enter summer dormancy. Tests of insecticides applied by aircraft for brown cotton bug control in 1960 and 1961 indicated that formulations of (1) carbaryl, (2) methyl parathion plus DDT, (3) endrin, and (4) DDT plus toxaphene or Strobane®, terpene polychlorinates (65% chlorine) were effective. New compounds of promise included Bidrin®, 3-hydroxy- N,N -dimethyl- cis -croton-amide dimethyl phosphate; and Imidan®, O,O -dimethyl S-phthalimidomethyl phosphorodithioate. Repeated applications at intervals of 7 to 10 days during both July and August were required.