EFFECT OF BISHKATALI PLANT (POLYGONUM HYDROPIPER) EXTRACT AGAINST RED FLOUR BEETLE, TRIBOLIUM CASTANEUM

Abstract

An investigation was carried out in the laboratory of the Department of Entomology, Hajee Mohammad Danesh Science and Technology University, Dinajpur during March-August, 2006, to evaluate the toxicity, repellency and residual effect of Bishkatali plant extracts in two solvent (chloroform and ethyl alcohol) against red flour beetle, Tribolium castaneum. Five doses (500mg/ml, 250mg/ml, 125mg/ml, 62.5mg/ml and 31.25mg/ml) of plant extract were used in the experiments. The plant extract in both solvent were moderately toxic to T. castaneum. The order of toxicity was- ethyl alcohol extract>chloroform extract after 24 and 72 hours treatment on the insect. Bishkatali plant extract in both solvents showed strong repellent effects against 7. castaneum. Extracts in chloroform showed better repellency than in ethyl alcohol. The highest repellency 87.3% was observed in chloroform extract at the beret dose of 500mg/ml. While with the same dose (500mg/ml) in ethyl alcohol extract, 80.3% repellency was observed. Bishkatali plant extract in chloroform and ethyl alcohol against 7. castaneum had remarkable residual effect in progeny reduction. The lowest numbers of F; adult progeny (32.7, 25.3 and 27.0) emerged from the wheat flour treated with 500mg/10g chloroform extract when parent released at 7, 12, 17 days after treatment respectively. Whereas with 500mg/10g ethyl alcohol extract, 38.0, 29.7 and 30.3 F; adult progeny emerged when parent released at 7, 12, 17 days after treatment respectively. The highest inhibition rate was observed 59.3% and 52.3% in chloroform extract and ethyl alcohol extract, respectively when treated with 500mg/10g dose and the adult released 12 days after treatment. Therefore, Tribolium castaneum can be managed effectively with Bishkatali plant extract.