Greenhouse Pesticide Mixtures for Control of Silverleaf Whitefly (Homoptera: Aleyrodidae) and Twospotted Spider Mite (Acari: Tetranychidae)

Abstract

This study assessed if tank mixing several commercially-available insecticides and miticides, in 2- and 3-way combinations, affects control of the silverleaf whitefly, Bemisia argentifolii Bellows & Perring, and the twospotted spider mite, Tetranychus urticae Koch, under greenhouse conditions. Pesticides evaluated were acetamiprid, bifenazate, buprofezin, and chlorfenapyr with each applied at the label rate. Salvia × superba Stapf was artificially infested with silverleaf whiteflies, and African marigold, Tagetes erecta L., was infested with twospotted spider mites. Once infested, the plants were sprayed with the designated pesticide treatments. Plants were evaluated 7 and 14 d after treatment. Efficacy was based on percent mortality of silverleaf whitefly and twospotted spider mite nymphs per plant. The 2- and 3-way pesticide mixtures exhibited no antagonistic activity, based on percent mortality values of silverleaf whitefly nymphs 14 d after treatment, with most mixtures resulting in >75% mortality. Similarly, none of the pesticide mixtures appeared to be antagonistic in regards to controlling twospotted spider mite nymphs with ≥90% mortality 7 d after treatment for 4 of the mixtures, and 100% nymphal mortality for all the mixtures 14 d after treatment. Results from this study suggest that greenhouse producers may tank mix the evaluated pesticides without negatively affecting the control of either silverleaf whitefly or twospotted spider mite during crop production.