ANTIFEEDANT ACTIVITY OF CONSTITUENTS OF ANDROGRAPHIS-PANICULATA (ACANTHACEAE) AGAINST THE GREEN RICE LEAFHOPPER, NEPHOTETTIX-CINCTICEPS (HEMIPTERA, CICADELLIDAE)

The antifeedant activities of crude extracts and a major compound (and rographolide) of Andrographis paniculata against female adults of the green rice leafhopper, Nephotettix cincticeps were tested using artifi cial diet and root-immersion methods, and were compared with the feedi ng-deterrent activity of commercial insecticides (cartap, bensultap, i midacloprid and nitenpyram). The crude extract and andrographolide sup pressed feeding of the female adult on an artificial diet at concentra tions of as low as 1 ppm. The lowest concentration of the crude extrac t that suppressed feeding activity by the root-immersion method was 1, 600 ppm. On the other hand, andrographolide was still effective at a c oncentration of as low as I ppm. The antifeedant activity of andrograp holide was similar to the feeding-deterrent activities of cartap and b ensultap, but it was lower than those of imidacloprid and nitenpyram.