Investigation of the Fungicidal Properties of Neem Tree Extracts as a Control for Mango Anthracnose
The production of fresh fruits and vegetables grown for local markets is severely limited by several insect pests and fungal diseases within the Commonwealth of the Northern Mariana Islands. Due to the economic crisis now present in the Commonwealth, the immediate need is to reduce dependence on off-island imports, increase the income of local producers and provide a safe and sustainable food supply. This project started in April 1999 with funding from EPA OPP/BPPD and AFT to evaluate the potential of indigenous neem, chinaberry and curry leaf plant extracts as effective, easily-applied and environmentally sound means for growers to manage insect pest and fungal pathogens in the field. However, due to difficulties in developing bioassays and handling plant extracts, the project cooperators decided to focus most of their attention on neem tree extracts as a control for anthracnose on mango. The additional funding and continuation of the project has focused on completing in vitro tests with neem leaf extracts, application techniques and field trials, and the propagation of large numbers of neem plants through tissue culture to distribute to growers.
Project goals and objectives
Comparative field trials to 1) evaluate the potential of indigenous neem; 2) determine sot-effectiveness; and 3) deliver information to local and regional producers.
Bacterial contamination of the in vitro studies continues to plague the project since neem extracts are not effective against bacteria. The aqueous in vitro studies still need to be completed. Work on application techniques will begin June 2001. The neem extraction preparation protocol for growers works very well. The neam leaf tissue is mascerated with liquid in a household blender and allowed to steep one hour for ethanol extraction and 24 hours for water. The supernatant is poured off for crop spraying and the plant debris (neem cake) is then dried and used as a natural fertilizer. The tissue culture work started in August 2000 and ran into difficulties due to new U.S. federal regulations governing shipment of "hazard materials." The basic tissue culture media contains potassium hydroxide and inorganic nitrates that are classified as "hazard materials." However, the materials can be shipped to Guam so they are now being shipped to the University of Guam and then delivered by hand to Saipan. While EPA funding has now ended for this project, it continues with USDA state Hatch funds through December 2001.
As of 2002, on Rota, two farmers have incorporated SA techniques into their farms. A farmer who has planted Neem and Chinaberry trees is using water extracts from these plants as a botanical pesticide. By growing his own insecticide, he has reduced the need for costly
commercial insecticides, which saves money and helps maintain the environment. On Saipan, four farmers have planted Neem and Chinaberry trees with the intent to use water extracts of seed and leaves as a botanical pesticide. Two farmers have completely eliminated commercial insecticides in their plantations by spraying water extracted Neem and Chinaberry on a monthly basis.