RECENT TRIALS WITH NEW ACARICIDES IN BRITISH COLUMBIA ORCHARDS

Abstract

In British Columbia, the following acaricides gave good control of the European red mite, Metatetranychus ulmi (Koch), and the brown mite, Bryobia arborea M. & A., when applied to apple trees at the pink bud stage: chlorfensone (p-chlorophenyl p-chlorobenzene sulphonate), fensone (p-chlorophenyl benzene sulphonate), chlorbenside (p-chlorobenzyl p-chlorophenyl sulphide), Genite 923 (2,4-dichlorophenyl benzene sulphonate), Chlorobenzilate (ethyl 4,4′-dichlorobenzilate), and Kelthane (1,1-bis (chlorophenyl) 2,2,2-trichloroethanol). Trithion [O,O-diethyl S-(p-chlorophenyl-thiomethyl) phosphorodithioate] gave good control of the European red mite; it was not tested in the pre-bloom stage against the brown mite.A summer spray of Kelthane or Trithion gave good initial and residual control of European red mite and brown mite; Diazinon (O,O-diethyl-O-[2-isopropyl-4-methyl-pyrimidyl (6)] thiophosphate) gave fair initial control but lacked residual effectiveness. Chlorobenzilate gave good control of the brown mite, the only species against which it was tested in the summer.Chlorfensone and chlorbenside injured apple foliage when applied at the pink bud stage. Chlorfensone, chlorbenside and fensone injured the fruit of some varieties and Genite 923 severely injured apple foliage when used in summer.