Insecticidal actions of several Philippine plants with emphasis on Vitex negundo L.
Water and organic solvent extracts of ten plants - "makabuhai" (Tinospora crispa (L.)), "lagundi" (Vitex negundo (L.)), "lagunding dagat" (Vitex trifolia (L.) Ssp. littoralis Van Steem), wild sunflower (Tithonia diversifolia A. Gray), derris (Derris elliptica (Rosch.) Benth), "kakawate" (Gliricidua sepium Jacq.), "hagonoi" (Chromolaena odorata (L.) R.M. King and H. Robin), "alagaw gubat" (Premna nauseosa Blco) and "alagaw" (Premna odorata Blco.) were evaluated for their insecticidal action against brown planthopper, green leafhopper, diamondback moth (DBM), and corn borer. Water extracts of "makabuhai" showed systemic and ovicidal toxicities and growth inhibitory effect (IGR). "Lagundi" and wild sunflower showed contact and ovicidal toxicities and IGR effect. Derris spp. and "luyang dilaw" showed contact and ovicidal toxicitis. Hexane (HE) and six volatile oil (VO) fraction of "lagundi" were further evaluated for larval and ovicidal toxicities on DBM. Three HE and VO fractions at 100 mg/ml reduced hatching of 70-80 percent of the eggs while two VO fractions were topically toxic to the larvae. The ethyl acetate extract caused larval abnormalities on DBM and corn borer. The active principle responsible for the ovicidal activity from the volatile oil is Beta-eudesmol. Nine of the ten plant extracts were practically nontoxic to rats when administered singly by oral or dermal routes. Derris spp. was determined to have an acute oral LD50 of 56.6 mg/kg (male rats) and 160 mg/kg (female rats) and dermal LD50 of 2000 mg/kg.
Rejesus, B. M., Maini, H. A., Ocampo, V. R., Dayrit, F. M., & Quintana, E. G. (1993). Insecticidal actions of several Philippine plants with emphasis on Vitex negundo L. Philippine Agriculturist, 76(4), 355-371.