• Comparisons of Insecticides on Fall Alfalfa Insect Populations, and Resultant Hay Yields and Quality

      Rethwisch, Michael D.; Reay, Mark; Berger, Lois; Hawpe, Erica; Grudovich, Jessica; Perez, Roger; Ramos, David; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2004-10)
      Three insecticide active ingredients (cyfluthrin, indoxacarb, and zetacypermethrin) were evaluated for their efficacy on several insects found in fall alfalfa in the low desert. Both liquid and wettable formulations were included for both cyfluthrin and zetacypermethrin, and four rates of indoxacarb were applied. Insect pressures were fairly low throughout the study. Pyrethroid chemistries (cyfluthrin, zetacypermethrin) provided excellent control of threecornered alfalfa hoppers for seven days after application while cyfluthrin applications resulted in lowest numbers of pale striped flea beetles during the same time period. All chemistries resulted in excellent control of the South American bean thrips (Caliothrips phaseoli). Indoxacarb treatments resulted in significantly increased levels of spotted alfalfa aphid, thought due to a reduction of big eye bugs noted with usage of this chemistry. Wettable formulations of both cyfluthrin and zetacypermethrin resulted in significant hay yield increases (0.1 tons/acre) when compared with their liquid formulations. An inverse yield trend was noted with indoxacarb rate. Usage of the liquid cyfluthrin chemistry also resulted in an unexplained quality decrease in this experiment.
    • Evaluation of miticides for potential use in alfalfa hay, 2004

      Rethwisch, Michael D.; Reay, Mark; Williams, Michael; Luna, Manuel; Grudovich, Jessica; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2004-10)
      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.