Abstract

Tenebrio molitor commonly known as yellow mealworms are major diverse group of insects. Both adults as well as larvae of T. molitor are ravenous feeders on a vast range of grains. This study was undertaken for approximation of the insecticidal effect of medicinal plants neem (Azadirachta indica) and tulsi (Ocimum tenuiflorom) against major stored product insect. The different amount of methanolic leaf extract of neem and tulsi were prepared and was analyzed for their insecticidal properties in laboratory against the larva as well as adult of T. molitor. At the dose of 10ml/kg grain, the larval mortality of T. molitor fluctuated from (32 to 57%) whereas adult mortality showed range from 27 to 52% The value at 25ml/kg and 50ml/kg grains fluctuated from (56 to 70%) and (67 to 82%) respectively in case of larval mortality, On the other hand adult mortality showed a slightly lower mortality range from 51 to 65% and 62 to 78% respectively. The chi-square test showed a substantial (p < 0.05) insecticidal effect of both the plants leaf compared to both larval and adult pest of stored grain but the neem had strong insecticidal effect as compared to tulsi against the larva and adult of T. molitor. The result of both the plants leaf extracts was promising as they retard larval growth as well as adult oviposition. Therefore, this led to explore the possibilities of use of medicinal plants leaf extract for insect control with due consideration to stored grains protection along with environment protection from the harmful synthetic insecticides.

Keywords

Tenebrio molitor, Insecticide, Yellow mealworm, Medicinal plant extract.

Received on 23/11/2020, Accepted on 01/12/2020, Published on 16/12/2020