LABORATORY AND FIELD-EVALUATION OF THE SELECTIVE ACARICIDES DICOFOL AND PROPARGITE FOR CONTROL OF TETRANYCHUS-URTICAE KOCH (ACARI, TETRANYCHIDAE) IN AUSTRALIAN COTTON

Efficacy of the selective acaricides dicofol (960 g a.i./ha) and propa rgite (1,500 g a.i./ha) for control of twospotted spider mite, Tetrany chus urticae Koch, on cotton was compared to profenofos (750 g a.i./ha ), a broad-spectrum acaricidal organophosphate which was the industry standard. Ground and aerial applications of propargite reduced mite po pulations to lower levels for longer than the other compounds. Ground applications of dicofol and profenofos provided equivalent efficacy, b ut it was only about half that of propargite. A side dressing of the g ranular insecticide aldicarb (1,500 g a.i./ha) was included at one sit e and, although it suppressed mite populations, was less efficacious t han propargite and uneconomic for commercial use. Dicofol and propargi te are now registered for commercial use in cotton. Results of laborat ory bioassays suggest that T. urticae populations collected from sever al cotton farms in New South Wales are presently susceptible to both c ompounds. The incorporation of these products into the insecticide res istance management strategy for cotton is discussed.