Abstract
The anitifeedant activities of crude extracts and a major compound (andrographolide) of Andrographis paniculata against female adults of the green rice leafhopper, Nephotettix cincticeps were tested using artificial diet and root-immersion methods, and were compared with the feeding-deterrent activity of commercial insecticides (cartap, bensultap, imidacloprid and nitenpyram). The crude extract and andrographolide suppressed feeding of the female adult on an artificial diet at concentrations of as low as 1 ppm. The lowest concentration of the crude extract that suppressed feeding activity by the root-immersion method was 1, 600 ppm. The antifeedant activity of andrographolide was similar to the feeding-deterrent activities of cartap and bensultap, but it was lower than those of imidacloprid and nitenpyram.
