Studies on the contact effect of spinosad on adult of Tribolium castaneum (Tenebrionidae), Sitophilus oryzae (Curculionidae) and Oryzaephilus surinamensis (Silvanidae) under laboratory conditions

Abstract :

Due to economical importance of stored-products insects and resistance to conventional insecticides, it is necessary to use novel and suitable compounds in control programs. Therefore, we evaluated the toxicity of spinosad to three important storage insects viz, Red flour beetle, Tribolium castaneum (Herbst), Rice weevil, Sitophilus oryzae (L.), and Sawtoothed grain beetle Oryzaephilus surinamensis (L.). One-day old adult insects were exposed to different concentrations of spinosad. The exposure times were 24, 48 and 72 hours in all experiments. Experiments were performed in complete randomized block design with 4 replications. After treatment the samples were held under constant conditions in rearing room at 27±2ºC, 65±5 R.H and 14 D: 10 L photoperiod. In contact tests for T. castaneum the maximum mortality rate was achieved with 500 ppm of spinosad after 72 h exposure. Application of 400 ppm of spinosad after 72 h caused maximum mortality in S. oryzae. For contact treatment the complete control of O. surinamensis was obtained with 500 ppm spinosad at 72 h exposure time. It is possible to recommend 500 ppm of spinosad for complete control of the tested insects through contact application. Estimated LC50 values of spinosad in 72 h after exposure for adults of T. castaneum, S. oryzae and O. surinamensis were 1287, 279 and 53.17 ppm, respectively. Results showed that O. surinamensis is most susceptible insect to spinosad in these experiments

Keyword :

Spinosad, Bioassay, Tribolium castaneum, Sitophilus oryzae, Oryzaephilus surinamensis

Author(s) : Sadeghi, G. R., Jahromi, M. G., Pourmirza, A. A., Abdolmaleki, A., Ebadollahi, A.
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Published Issue : 2011 Vol. 6 Number 1

2011 Vol. 6 Number 1