Assessments on Insecticidal and Fungicidal Activities by Aerial Part Extracts from Several Compositae Plants

Methanol leaf extracts from 16 species of compositae plants were tested for their insecticidal and larvicidal activities against Tetranychus urticae Koch, Panonychus citri, Aphis gossypii Glover, and Myzus persicae (Sulzer) by leaf-dipping method and foliar application. Plant extracts at 5,000 ppm had higher insecticidal activity against Tetranychidae than Aphididae. Among 16 different plant extracts Youngia sonchifolia, Gnaphalium affine and Artemisia princeps extracts showed higher insecticidal and larvicidal activities against T. urticae. Strongest insecticidal activity against T. urticae was observed from the extracts of Youngia sonchifolia 72 days after application. The methanol extracts from Kalimeris yomena and Siegesbeckia glabrescens showed excellent efficacy against Pyricularia oryzae Cavara, and Artemisia iwayomogi and Bidens frondosa extracts against Botrytis cinerea Persoon ex Person while no antifungal or antibacterial activity of all the extracts were observed against Xanthomonas oryzae pv oryzae and Pseudomonas solanacearum (Smith) Smith. This results show that the methanol extracts from Compositae plants had potent insecticidal and bacterial activities against agricultural insects and pathogens even though the activities from plant extracts showed lower than synthetic pesticides