Spinosad was evaluated on hard red winter wheat stored in round metal bins on three Kansas farms during 2002-2003. On each farm, four bins each holding approximately 75 metric tons received different treatments as follows: untreated control, spinosad at 1 mg (AI)/kg, chlorpyrifos-methyl (Reldan) at 3 mg (AI)/kg, and spinosad, 1 mg/kg + chlorpyrifos-methyl, 3 mg/kg. Grain samples were removed with a trier monthly starting July 2002 until May 2003 to determine types and numbers of insects present. Grain samples were equilibrated to 13% moisture in a laboratory chamber and exposed to adults of the lesser grain borer, red flour beetle, and rusty grain beetle. Both the field and laboratory observations showed that spinosad and spinosad + chlorpyrifos-methyl treatments to be effective in completely suppressing insects. The chlorpyrifos-methyl treatment lost effectiveness after 2 months. Large numbers of insects were observed in the untreated control bins. These results suggest that spinosad could be a potential grain protectant for use on stored wheat in Kansas.
Species 1: Coleoptera Bostrichidae Rhyzopertha dominica (Lesser grain borer)
Species 2: Coleoptera Tenebrionidae Tribolium castaneum (Red flour beetle)
Species 3: Lepidoptera Pyralidae Plodia interpunctella (Indian meal moth)
Keywords: OP alternative, Grain protectant
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