OCCURRENCE OF CYHEXATIN AND DICOFOL RESISTANCE IN THE EUROPEAN RED MITE, <i>PANONYCHUS ULMI</i> (KOCH) (ACARI: TETRANYCHIDAE), IN SOUTHERN ONTARIO

Abstract

Abstract Laboratory bioassays showed the occurrence of 8.5-fold resistance to cyhexatin and ca. 15-fold resistance to dicofol in laboratory-selected populations of European red mite ( Panonychus ulmi (Koch)). Surveys, in 1984, of 45 orchards, using field-collected mites exposed to discriminating concentrations of cyhexatin or dicofol, detected resistance to cyhexatin in ca. 29% of the populations. Resistance to dicofol was identified in 2 of 45 assays.