Toxicity of Chlorinated Phenyl Benzenesulphonates to Winter Eggs of the Fruit Tree Red Spider Mite, Metatetranychus ulmi (Koch)

Abstract

THE mite ovicidal activity of a number of substituted phenyl benzenesulphonates toward the eggs of the two-spotted spider mite, Tetranychus bimaculatus Harvey, was examined by Kenaga and Hummer¹, who found that substitution by bromine or, better, chlorine in the para-position in both phenyl rings led to compounds of considerable activity. By far the most active was 4-chlorphenyl 4-chlorbenzene-sulphonate, and this has now been developed commercially in the United States. Afterwards, Kirby and McKinlay², using summer eggs of the fruit tree red spider mite Metatetranychus ulmi (Koch), and Read and Smith³, using eggs of the glasshouse red spider mite Tetranychus telarius L., found that 4-chlorphenyl benzenesulphonate (CPBS) was at least as potent as 4-chlorphenyl 4-chlorbenzenesulphonate (CPCBS) toward both these eggs. Field experience in 1952 has shown that the former, especially when applied in conjunction with an acaricide, can give remarkably persistent control of the fruit tree red spider mite under English conditions, but considerable damage may occur in a year like 1952 to fruits of certain apple varieties, notably Worcester Pearmain.