The neem tree (Azadirachta indica), whose seed and leaf extracts are known to kill more than 60 types of insects, has recently been the subject of several interesting studies. Researchers at Virginia Polytechnic Institute and State University effectively control the Colorado Potato Beetle (CPB) in eastern Virginia using extracts from seed kernels of the tree. Meanwhile, in Louisiana, USDA researchers have found that leaves from the India native may block fungi from producing aflatoxins in stored grains. Another study in Israel conducted on pest and predacious mites indicates that neem extracts are considerably more toxic to the pest than to the predator.

IRRI and Neem Cake Production

International Rice Research Institute entomologist R.C. Saxena and others are researching the effects of neem on green leafhoppers that attack rice crops. Studies show that leafhoppers feed less, grow poorly and lay fewer eggs on rice plants that have been sprayed with the oil. Neem cake applied to ricefields reduces nitrogen loss and may also encourage nitrogen fixation in rice. IRRI has developed a process of producing neem seed 'bitters' from crushed kernals using water.

Write R.C. Saxena at IRRI, P.O. Box 933, Manila, Philippines. Tropical Pest Management, 1988, 34 (3) p. 358.