Control of Pulse Beetle, Callosubruchus Maculatus (F.) (Coleoptera: Bruchidae) in Different Cereals Using Spinosad Dust in Storage Conditions

Abstract

Effectiveness of spinosad dust formulation, that contains 0.125% spinosad, was evaluated against adults Callosubruchus maculatus (F.) on four commodities: chickpea, split pea, cowpea and lentil. Spinosad was applied at three dose rates: 0.1, 0.2 and 0.3 g/kg, corresponding to 0.125, 0.25 and 0.375 mg/kg of the active ingredient, respectively. The experiment was carried out at 27°C and 55±5% relative humidity. Adults mortality was measured after 1, 2, 5 and 10-days of exposure. After the 10-day mortality count, all surviving insects were removed and samples retained under the same conditions for a further 35 days to assess progeny reduction. Mortality of exposed individuals in all treated commodities was low at 1-day exposure even at 0.3 g/kg and did not exceed 20%. As expected, mortality increased with the increase of exposure interval and dose rates. A significant difference was observed among the four commodities. After 10 days of exposure, mortality reached 100% in all commodities except for split pea. The application of spinosad significantly reduced progeny production in four commodities tested in comparison with the untreated ones. High reduction in progeny production was recorded when spinosad was applied at the rate of 0.3 g/kg on split pea and cowpea (94.33 and 94.21%, respectively). The results of our study clearly revealed that spinosad dust could be successfully used as a grain protectant against C. maculatus. Further experimentations still need to be done to examine higher dose rates and long-term use in different commodities.