Control of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) with Spinosad Dust Formulation in Different Oilseeds


Abstract: The insecticidal effect of spinosad dust, a formulation that contains 0.125% spinosad, was evaluated against adults of Tribolium castaneum (Herbst) on 4 commodities: safflower, sunflower, sesame, and canola. Fifty grams of each commodities were treated with 3 doses of the formulation: 100, 200, and 300 ppm, (corresponding to 0.125, 0.25, and 0.375 mg kg^{-1} a.i., respectively) at 27 °C and 60 ± 5% relative humidity. The mortality of T. castaneum adults was measured after 1, 2, 7, 14, and 21 days of exposure. After the mortality count on day 21, all surviving insects were removed while the samples were kept under the same conditions for a further 45 days to assess progeny production. The number of emerged individuals (adults and immatures) was then counted as progeny production. The increase of dose and exposure interval increased mortality. Significant differences were recorded among the 4 oilseed types and the mortality of T. castaneum on sesame was significantly lower compared to the other commodities. After 21 days of exposure, mortality reached 100% only on safflower at the highest dose (300 ppm). Progeny production was significantly lower on all 4 treated commodities in comparison with the untreated ones. Complete suppression in progeny production was achieved on safflower and sesame only at 300 ppm. In conclusion, our research revealed that application of spinosad dust formulation at higher rates and for longer exposure intervals could control T. castaneum in different oilseeds.

Keywords: Tribolium castaneum, oilseeds, progeny production

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