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United States Department of Agriculture

Agricultural Research Service

Research Project: CONTROL OF MINOR CROP PESTS AND DISEASES

Location: Tropical Crop and Commodity Protection Research

2011 Annual Report


1a.Objectives (from AD-416)
1. The objectives of this cooperative agreement are to develop economical and environmentally friendly pest and disease management strategies for Hawaii’s economically important and potentially important crops, all classified as minor crops. 2. Develop and implement multidisciplinary biologically based pest/disease management technologies which are environmentally acceptable and have low cost/benefit ratios. • Vectored vegetable and fruit viruses. • Management of insect pests and diseases to meet yield, quality, and quarantine standards. 3. Analyze and evaluate the significance of current disease and pest management strategies and policies, and develop changes in strategy or new policies that will "level the playing field" with competitors (e.g. quarantine regulations, U.S. governmental assistance to foreign countries, proprietary information, pesticide regulations, and the export of competitive technology).


1b.Approach (from AD-416)
The approach to this project is to address the development of economical and environmentally friendly pest and disease management strategies for Hawaii’s economically important and potentially important crops. Utilize traditional breeding techniques and genetic engineering to develop horticulturally acceptable cultivars resistant to major disease and insects of Hawaii’s most important crops. Develop pre-harvest and post-harvest disease and insect management systems for Hawaii’s most important crops that are environmentally acceptable and have low cost/benefit ratios. Identify and characterize any environmental, social and economic impacts of technologies and processes for pest and disease control in order to allow the production and interstate and international movement of Hawaii agricultural products. Analyze and evaluate the significance of current disease and pest management strategies and policies, and develop changes in strategy or new policies that will “level the playing field” with competitors (e.g. quarantine regulations, U.S. governmental assistance to foreign countries, proprietary information, pesticide regulations, and the export of competitive technology. Documents SCA with University of Hawaii; formerly 5320-22430-021-06S (8/09). Formerly 5320-22430-023-11S(06/11).


3.Progress Report

This project supported 7 subprojects covered under this progress report. It was found that Maize mosaic virus (MMV) infection on corns modulated the density and dispersal of the planthoppers according to the stage of a plant infected. At an early stage of infection, the virus may trigger the vector population to produce more short winged form (brachypters); however, at the late stages of infection, the virus may promote the vector to disperse by triggering the development of a larger proportion of the long winged form (macropters) in an aphid population. This finding stresses the importance of proper field management such as rouging of infected plants and volunteer growths. Transgenes derived from over 52 transgenic lines of Mexican lime (Citrus aurantifolia) shown resistance to Citrus tristeza virus (CTV) were introduced into the Mexican lime genome in a variety of configurations, including sense, antisense, inverted repeat, and stacked. All lined assayed appeared to have harbored between 1 and 6 copies of transgene. These 52 transgenic lines were exposed to the brown citrus aphid (Toxoptera citricida) harboring CTV. Of these lines, 17 remained uninfected by CTV. Volkamer lemon (Citrus volkameriana) displaying symptoms resembling citrus leprosies was examed and found that the suspected virus on the Volkamer lemon was HGSV (Hibiscus green spot virus), a previously undescribed disease of citrus in Hawaii. An aphid-specific parasitoid that attacks and kills melon aphids was successfully imported and released on Kauai. The new natural enemy has become established in the field at three taro-growing sites on that island. Results of the project showed that the new parasitoid could also attack several other aphid pests in the State, which will add to its potential for aphid control. Releasing the aphid-specific parasitoid would not pose any environmental risks against non-target species as all aphid species in Hawaii are invasive. Finally, using polymerase chain reaction (PCR), the gut contents of predaceous nematodes, Mononchus and Mesodorylaimus which were feeding on burrowing, reniform, or microbivorous nematodes were anlayzed. Initial results showed that amplification of reniform nematode DNA occurred in the gut contents of 49.5% of the predators tested. In addition, 57% of Mononchus and 42% of Mesodorylaimus were tested positive of reniform nematode DNA, indicating that Mononchus is more efficient predator of reniform nematodes than Mesodorylaimus. The project was monitored via meetings, site visits, and telephone and email communications.


Last Modified: 11/24/2014
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