Investigation of the Fungicidal Properties of Neem Tree (Azadirachta indica) Extracts as a Control for the Mango Anthracnose Fungus (Colletotrichum gloeosporioides)
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 will 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; determine the cost-effectiveness of using this management system; and disseminate the resulting information and the means to produce plant extracts to local and regional producers.
Project goals and objectives
In FY99, investigated ethanolic extracts of neem in the lab to determine the relationship between concentration and fungicidal activity
In FY2000, tested aqueous neem extracts
Due to the difficulties in developing bioassays and handling plant extracts, the cooperators decided to focus most of their attention on neem tree extracts as a control for anthracnose on mango. They first conducted a bioassay of neem leaf extracts to determine the relationship between concentration and fungicidal activity. They then conducted laboratory trials using ethanolic and aqueous neem leaf extracts against Colletotrichum gloeosporiodes and Phomopsis magiferae, the causal agents of anthracnose and stem-end rot, respectively, on mango. Ethanolic extracts were 100 percent effective within seven days. They are now fine-tuning the ethanolic extract for the most effective, least amount required and completing the aqueous trials. Concurrently, they developed a simple neem extract preparation protocol for growers. They simply macerate leaf tissue with liquid in a household blender, let it steep for an hour and use the supernatent for crop spraying. They also developed application techniques and began to field test neem extracts for their effectiveness to control athracnose. They plan to begin rapid propagation of neem trees via tissue culture for distribution to the public for planting in Fall 2001. Because of good press coverage on the project, requests for neem trees are already piling up. This will be the first time that tissue culture has been used in the Northern Marianas Islands.