Evaluation of miticides for potential use in alfalfa hay, 2004

Five treatments were applied at time of bale removal to evaluate several products for twospotted spider mite (Tetranychus urticae) management in alfalfa hay. Mite numbers were very high prior to this harvest and were assumed to be more than adequately present for this study. Data were obtained at six, fifteen and eighteen days post treatment. Data at six days after application documented that only ZealTM and Trilogy7 had fewer spider mites than the untreated check, but data also indicated that western flower thrips (Frankliniella occidentalis) were also probably present and feeding on mites. Western flower thrips were present in almost equal numbers as twospotted spider mites at fifteen days post treatment and mite numbers had decreased greatly from the previous sampling date. Mite numbers/stem were similar at eighteen days to that of fifteen days post treatment. Thrips predation was thought to obscure differences in spider mite populations resulting from treatments in this experiment, and therefore data from this experiment should be so noted when future treatment decisions are considered