Insecticidal and Antifeedant Activity of Andrographis paniculata as Rice Grain Protectant against Red Flour Beetle (Tribolium castaneum Herbst)

Abstract

The red flour beetle (Tribolium castaneum Herbst) is the most common stored-product insect pest infesting rice, which acts as vector for several fungal post-harvest diseases. To eradicate such pest, fumigation with chemicals is often used. As a natural alternative, this study explored the potential of Andrographis paniculata, an indigenous herb in the Philippines, as an antifeedant agent against T. castaneum. Three treatment groups were prepared, consisting of 2kg infected rice with 50 starved unsexed adult red flour beetles. Two grams of A. paniculata crushed leaves were placed inside a teabag (5.5 cm x 7 cm). Different amounts of A. paniculata tea bags (2 g, 4 g, and 6 g) were used for each treatment to determine its toxicity and antifeedant effect. Gathered data were further analyzed by analysis of variance (ANOVA) to compare the significant differences among treatments. Results of the study showed that among the treatments, three teabags (6g) of A. paniculata crushed leaves exhibited the highest percent insect mortality (50%) and lowest percent weight loss (1.87%) of rice. Therefore, this study suggests that three teabags of A. paniculata powder may be used for the efficient management of T. castaneum infestation and reduce the weight loss of rice in storage.