Nutritional indices of Tribolium castaneum (herbst) and its response to plant extracts in relation to three types of flours

Abstract Tribolium castaneum is a major pest of stored grains and processed commodities. The present experiments were conducted to check the nutritional indices of T. castaneum reared on corn, wheat and barley flour. Mortality effect of acetone extracts of various concentrations (5.0, 10.0 and 15.0%) of Nerium oleander from three different cultivars (yellow, pink and white) was also evaluated against T. castaneum at different exposure intervals (24, 48 and 72h). Maximum Consumption Index (CI) (15.57 mg/t), Relative Growth Rate (RGR) (0.027mg/t) and Approximate Digestibility (AD) (78.42 %) were observed in Corn flour and minimum CI (6.6 mg/t), RGR (0.024 mg/t) and AD (35.02%) was recorded in barley flour. Maximum and minimum value of Efficiency of conversion of ingested food (ECI) was observed in barley and corn flour respectively. Maximum and minimum adult weight and flour loss weight was observed in corn and barley flour respectively. The mortality of T. castaneum increased with increase in concentration and with increase in time interval. The results also revealed that highest percent mortality (24%) was achieved when extract of yellow cultivar of test plant with (15%) concentration apply for 72hrs and with white cultivar of test plant resulted in (0.0%) mortality at 5% concentration after 24hrs of application. From these results, it was concluded that corn flour could be a suitable rearing medium for the growth of T. castaneum, while yellow cultivar of N. oleander could be placed in IPM for the control of this pest.