INSECTICIDAL PROPERTIES OF MARIGOLD (TAGETES ERECTA) PLANT EXTRACT AGAINST RED FLOUR BEETLE, TRIBOLIUM CASTANEUM (HERBST.) (TENEBRIONIDAE: COLEOPTERA)

Abstract

The study was carried out in the laboratory of the Department of Entomology, Hajee Mohammd Danesh Science and Technology University (HSTU), Dinajpur during March to August 2017 to evaluate the toxicity, residual and repellent effects of marigold leaf and flower extracts in methanol solvent against the red flour beetle, T. castaneum. Four doses of marigold plant extract were applied viz. 80, 60, 40, 20 mg/ml on adult and 10, 5, 2.5 and 1.25 mg/ml on larva of the red flour beetle. Result revealed that both the marigold leaf and flower extracts were toxic to red flour beetle. Marigold flower extract showed higher toxicity than marigold leaf extract at different hour after treatment application (HATs). Marigold leaf and flower extracts showed strong repellent effects against both the adult and 5th instar larva. The marigold flower extract showed the higher repellency (80.74%) and the lower repellency (74.44%) was found in marigold leaf extracts on adult beetle. Similarly, on 5th instar larva, the higher repellency (85.56%) was found in marigold flower extract and the lower repellency (67.41%) was recorded in marigold leaf extract. Marigold leaf and flower extracts also showed result of wheat flour by reducing adult emergence over control. Based on the adult emergence, the marigold flower extract showed the higher residual toxicity. Considering the toxicity, repellency and residual effect, marigold plant extracts were effective against red flour beetle.