Antifeedant Effect of Some Medicinal Plant Extracts Against Rice Weevil.

Abstract

At present, insecticides with raw materials of active compounds from plants have become a strategic alternative, because they are easily obtained and produced. In an attempt to find natural and cheaper methods for the control of rice weevil (Sitophilus oryzae L.), some useless waste of local medicinal plant extracts was evaluated. This study aimed to evaluate the antifeedant effect of various medicinal plant extracts on rice weevil (Sitophilus oryzae L.). The experimental study using a completely randomized design of two factors, i.e., source of the extract in 7 types of medicinal plant waste and the exposure time of extracts in 0, 1, 2 and 3 h. The antifeedant effects were evaluated after 3 weeks by measuring feed consumption (FC), feeding deterrent index (FDI) and rice weevils' mortality. Data were analyzed using variance analysis. The statistical analysis showed that the differences in exposure time contributed significant influence (α<0.05) on FC, FDI and mortality. The lowest FC occurred at the 3 h exposure treatment, i.e. on the extract of Amomum cardamom plant, while the highest FC was found in the treatment of Curcuma mangga plant extract. The values of FDI and mortality at the 3 h extract exposure were 31.53-87.16% and 42.4-64%, respectively with the highest value in the treatment of A. cardamomum. At last, these findings inform peoples that the waste of medicinal plants, especially cardamom is possible to be developed as botanical insecticides for rice weevils.