Two-Spotted Spider Mite and Hop Aphid Control on Cluster Hops with Acaricides1

Abstract

Thirteen compounds in 1966 and 12 compounds in 1967 were tested in replicated plots of cluster hops for control of two-spotted spider mites, Tetranychus urticae Koch, and hop aphids, Phorodon humuli (Schrank). Dicofol and tetradifon, used as standards, were as effective as any of the compounds tested for mite control. Azodrin® (3-hydroxy-N-methyl- cis -crotonamide dimethyl phosphate) and Tranid®( exo -5-chloro-6-oxo- endo -2-norbornanecarbonitrile O -(methylcarbamoyl) oxime) were effective for control of both mites and aphids. Either could replace the presently used combinations of dicofol-malathion or tetradifon-malathion. Carbofuran, phorate, and phosalone were effective for control of hop aphids. Bayer 58733 (2,2,2-trichloro- N -(pentachlorophenyl) acetimidoyl chloride) was the only compound to show possible selective survival of phytoseiid mites. Mites at low population densities had a higher adult:egg ratio than mites at high population densities.