Orchard Mite Studies in 19501

Abstract

Of the 4 spp. of mites occurring in w. New York orchards only Tetranychus bimaculatus and Paratetranychus pilosus are of major importance. The common name of four-spotted spider mite is proposed for Septanvchus canadensis McG. DN-289 (21.5% dinitro sec.-butyl phenol) was inferior to a 2% petroleum oil spray in killing the winter eggs of the European red mite. Tetraethyl pyrophosphate, 1% petroleum oil and p-chlorophenyl p-chlorobenzene-sulfonate, applied prior to bloom, were more effective against the European red mite than the winter ovicide sprays tested. 16 acaricides were tested against summer infestations of the European red mite and the two-spotted spider mite. All the 8 organo-phosphorous compounds killed hatched forms of the mites. Residual action up to one month was attained from a single application of p-chlorophenyl p-chlorobenzene sulfonate. Promising results were obtained in controlling the two-spotted spider mite through the use of 2 systemic phosphorous materials applied to the orchard ground cover.