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Efficacy of Spinosad Formulations to Control Stored Grain Insects

Robertson, James Barrett
Two studies were conducted to determine if different formulations of Spinosad provide the same level of control against insect pests in stored wheat, and to examine a possible chemical antagonism phenomenon that occurs when Spinosad is mixed with chlorpyrifos-methyl and applied to wheat. Different formulations of Spinosad were used, and bioassays were conducted on various insect pest species of stored wheat. Chemical analyses were performed to examine degradations of treatment active ingredients (AI) over time. Differences in efficacies between two or more of the Spinosad formulations were observed in bioassays, depending on insect species tested. Results determined the liquid formulation was the least effective formulation of Spinosad, and the dust formulation was most effective. Evidence of antagonism was observed in bioassays containing certain species. Chemical analyses showed possible losses in AIs when mixed.