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Research Project: Exotic Whitefly Pests of Vegetables and Ornamental Plants

Location: Subtropical Insects and Horticulture Research

Project Number: 6034-22320-003-000-D
Project Type: In-House Appropriated

Start Date: Sep 14, 2015
End Date: Sep 10, 2020

Objective 1: Investigate biological control and ecological interactions of whiteflies with their natural enemies using banker plant systems to promote environmentally sound control in vegetable and ornamental crops. Sub-objective 1b: Determine the compatibility of insecticide regimes with beneficial insects and natural enemies used in banker plant systems. Objective 2: Investigate structural, physiological, molecular and chemical aspects of the whitefly feeding process and identify inhibitor strategies/molecules such as but not limited to feeding disruptors and peptide inhibitors of disease transmission than can be used in the development of novel interdiction strategies envisioned to work either through production of transgenic plants or application of chemical treatments that block feeding/disease transmission. Sub-objective 2a: Develop transgenic tobacco expressing enzymatic inhibitors of whitefly salivary sheath formation test for resistance to Bemisia tabaci feeding. Sub-objective 2b: Test application of discovered small molecule inhibitors of sheath formation for their effect on whitefly feeding on tomato. Sub-objective 2c: Conduct proteomic analysis of salivary exudates to identify salivary sheath structural and biosynthetic proteins. Objective 3: Use molecular strategies to develop disease resistant banker plants to support large numbers of whitefly populations for production of biocontrol agents for use in the greenhouse.

Research will focus on constructing a nonflowering papaya banker plant through biotechnology that is resistant to both papaya ringspot virus and powdery mildew. Strategically timed insecticide applications including neonicotinoids in the rotation regimes will be evaluated against MED (Q-biotype whitefly) for whitefly efficacy and compatibility with two of the natural enemies used in our banker plant systems: the predatory mite, Amblyseius swirskii, and the whitefly parasitoid, Encarsia sophia. Development and testing molecular inhibitors of whitefly feeding processes with specific emphasis on the processes that must occur for the whitefly to develop a successful feeding event. Two main objectives include: 1) Continued characterization of the whitefly salivary sheath biosynthesis and composition. We already have basic compositional data and some knowledge on structural arrangement. Molecular, biochemical and structural analyses will continue to identify key biosynthetic enzymes and sheath structural components. 2) Evaluation of inhibitors of sheath formation as control agents. This evaluation will be performed using artificial diet assays and development of transgenic tobacco expressing inhibitors and conducting bioassays where the whitefly feed on the artificial diet or the transgenic plants.