Tarnished Plant Bug Injury on Six Strawberry Cultivars Treated with Differing Numbers of Insecticide Sprays

Abstract

Six strawberry ( Fragaria x annassaDuch.) cultivars known to vary in susceptibility to tarnished plant bug ( Lygus lineolarisP. de B.) injury (apical seediness) were grown for two seasons under three insecticide regimes (three sprays, one spray and no spray) to determine if differences in susceptibility could be used to modify chemical controls for this insect. The most susceptible cultivars harbored more nymphs than the least susceptible cultivars. Increased marketable yield as a result of insecticides was most pronounced on susceptible cultivars. Differences in injury among cultivars were greatest when no insecticide was applied. ‘Honeoye’ and ‘Sparkle’ had the least apical seediness, followed by ‘Redchief,’ ‘Guardian’ and ‘Kent.’ ‘Mic Mac’ consistently had the highest level of injury. When insecticide applications were reduced, apical seediness did not increase significantly for cultivars exhibiting low susceptibility. Chemical name used: O, O-dimethylphosphorodithioate of diethylmercaptosuccinate (malathion).