Laboratory and Field Evaluation of the Selective Acaricides Dicofol and Propargite for Control of Tetranychus urticae Koch (Acari: Tetranychidae) in Australian Cotton

ABSTRACT Efficacy of the selective acaricides dicofol (960 g a.i./ha) and propargite (1,500 g a.i./ha) for control of twospotted spider mite, Tetranychus 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 populations to lower levels for longer than the other compounds. Ground applications of dicofol and profenofos provided equivalent efficacy, but it was only about half that of propargite. A side dressing of the granular insecticide aldicarb (1,500 g a.i./ha) was included at one site and, although it suppressed mite populations, was less efficacious than propargite and uneconomic for commercial use. Dicofol and propargite are now registered for commercial use in cotton. Results of laboratory bioassays suggest that T. urticae populations collected from several cotton farms in New South Wales are presently susceptible to both compounds. the incorporation of these products into the insecticide resistance management strategy for cotton is discussed.