- Fruits: bananas, general tree fruits
- Pest Management: disease vectors, economic threshold, field monitoring/scouting, integrated pest management, prevention, sanitation
Hawaii is the major banana producer in the U.S., with a total area of 1,500 acres planted on 200 farms; the commodity value for the state is US$10.6 million. The U.S. banana market is large. In 2002 the country imported US$1 billion worth of bananas from countries in Central/South America and Southeastern Asia. The major threat to the Hawaii’s banana industry is banana bunchy top disease (BBTD). This is the most serious viral disease of banana. Bunchy top occurs throughout the Pacific Basin and is caused by the phloem-limited nanovirus banana bunchy top virus (BBTV). Plants infected with BBTV do not produce fruits, and the pathogen also spreads to suckers through the rhizome, eliminating production on the infected plant. BBTV is naturally spread only by an efficient vector, the banana aphid (Pentalonia nigronervosa), in a persistent manner. This disease, accidentally introduced into Hawaii in 1987, is now established all the major islands in the State, and currently is a production limiting factor for banana growers. In Hawaii, control of BBTD is done by roguing symptomatic plants and applying insecticides to entire plantations. It has previousy been shown that insecticides are not efficient in controlling the spread of BBTV. Because aphid vectors are usually present only on suckers, pesticide application to all plants is i) inefficient, ii) expensive, and iii) environmentally harsh, among other associated problems. Roguing of symptomatic plants, the current strategy to eliminate pathogen sources, does not preclude the spread of disease because vector transmission of the pathogen can occur during a period when symptoms are not present on infected plants. Hawaii growers have been able to manage BBTD spread in only a few instances, and the disease remains the primary limiting factor for banana production in the state. Development of economically and environmentally sustainable approaches to control BBTD is essential for the survival of the banana industry in Hawaii. We propose to gather basic information about BBTD in Hawaii, including disease spread and aphid biology and ecology. Once results have been obtained and analyzed, it will be possible to determine disease spread characteristics, and test management hypotheses developed from epidemiological models. Researchers, extension agents, and growers will be involved in all elements of the project, since most of the work is field-oriented with immediate application.
Project objectives from proposal:
Objectives include mapping of diseased plantations, studies on aphid biology and ecology, and testing of disease control strategies together with growers. The development of new bunchy top disease control guidelines is an objective, which will be made available to growers through our College's extension office.