Phytochemical Screening and Insecticidal Activity of Cyperus iria, Fimbristylis globulosa and Fimbristylis miliacea toward Sitophilus oryzae L.

The rice weevil, Sitophilus oryzae is one of the famous insect pests that cause the low quality of the rice seeds. Fimbristylis miliacea, Fimbristylis globulosa and Cyperus iria are sedge weeds that are common near swampy areas. These weeds are classified as potential due to their high nutritional value and chemical compound content. Natural compounds from plant extracts prove the potential to develop as a new natural bio-insecticide in terms of agriculture usage. Cyperus iria, Fimbristylis globulosa and Fimbristylis miliacea extracts were screened for their secondary metabolite constituents. All extracts at a concentration of 1% were also evaluated for their feeding and fumigant toxicity against Sitophilus oryzae. Phytochemical analysis showed the presence of terpenoids, saponin, and phenolics in Fimbristylis miliacea extract. Fimbristylis globulosa extract contains flavonoids, terpenoids and phenolic. Phenolic and flavonoid compounds are also included in Cyperus iria extract. However, Fimbristylis miliacea extract showed the strongest feeding toxicity against Sitophilus oryzae at a mortality of 100% at the highest concentration starting after 6 hours, while the other extracts had moderate feeding toxicity with a mortality rate (50-80%) at a low of concentration. Fimbristylis miliacea extract also showed a higher repellency in the fumigant toxicity at (100%) maximum in 5 hours.