A laboratory testing programme for assessing field performance of acaricides against Tetranychus urticae (Koch)

Abstract

A sequence of four laboratory tests to measure pesticide tolerance of horticultural pests and their response to spray impact and residual deposits is described.

Results of tests using demeton-S-methyl, carbophenothion, and dinobuton against a suspected organophosphorus-resistant strain and a susceptible strain of Tetranychus urticae (Koch) mites are presented.

The resistant strain was found to have a high level of resistance and a strong avoidance reaction to demeton-S-methyl and a moderate resistance to carbophenothion in comparison with the susceptible strain.

An apparatus for dosing mites and equally small first instar insect larvae with drops of commercially formulated pesticides is described.