EFFECTIVENESS OF SPINOSAD AGAINST TRIBOLIUM CASTANEUM (HBST) (COLEOPTERA-ENEBRIONIDAE)

Abstract

Studies were conducted in the Grain Research Training and Storage Management Cell (GRTMC), Department of Agri- Entomology, University of Agriculture Faisalabad, to evaluate the effect of Spinosad (0.25%, 0.50%, 0.75% and 1.0%) at different doses with different exposure times against Tribolium castaneum. Spinosad at 1%, 0.75%, 0.50% and 0.25% concentrations killed 61.85%, 55.56%, 45.93% and 32.59% Tribolium castaneum adults respectively which were statistically different (P=0.05) than the percent kill of the test insect in the control. The toxicity of spinosad to the test insect was also dose dependent, the higher the concentration, the significantly more mortality of the insect. Exposure of the test insect to spinosad for different time intervals (24, 48 & 72 hours) resulted into different percent mortality of T. castaneum. The percent mortality of the insect after 72hours (51.33%) exposure was significantly different from the percent mortality after 48hours (40.89%) and 24hours (25.33%) exposure. The interaction effect of 1% spinosad and 72 hours exposure gave 75.55% kill, which was significantly (P=0.05) more than the percent kill of the other concentrations & exposure time except the interaction effect at 0.75% spinosad exposed for 72 hours. The population build-up of T. castaneum after exposure to Spinosad at different concentrations and different exposure time was significantly lower than that in the control. The negative effect of the chemical on the population build up of T. castaneum was dose and exposure time dependent.