Location: Subtropical Plant Pathology Research2013 Annual Report
1a. Objectives (from AD-416):
To characterize crop and weed hosts, and insect vectors of Groundnut ringspot virus to facilitate development of better management options for this newly emerging virus infecting Florida fresh-market vegetables including tomato and pepper.
1b. Approach (from AD-416):
The nucleic acid-based diagnostic test for Groundnut ringspot virus previously developed by ARS Scientists will be used to analyze natural and/or experimental plant hosts (crops and weeds) for this virus to develop a host range for the virus. Locally important thrips species will be analyzed for their ability to transmit the virus. The information generated from this research should be useful to fresh-market vegetable growers, the specialty crop industry, Florida Cooperative Extension Service, private crop consultants and FDACS to guide development of management strategies for this newly emerging virus.
3. Progress Report:
This research relates to inhouse project objectives 1). Characterize ecology, biology, epidemiology, molecular genetics, and vector and host (crop and weed) interactions of domestic, exotic, newly emerging, and re-emerging pathogens, 2). Develop/refine rapid, sensitive reliable detection/sampling methods for pathogens, and 3). Develop or improve comprehensive integrated disease management strategies. Additional thrips transmission experiments using thrips populations collected by ourselves and collaborators. Processing of thrips and plant samples continues to refine methodology and obtain additional information on which local thrips species may transmit GRSV in Florida. This represents substantial progress in project efforts to determine which local thrips species are important for GRSV transmission in Florida. Preliminary thrips transmission experiments with TCSV have been initiated to extend previous project work with GRSV. An experimental host range test with GRSV was completed. Over 45 plant species have been tested, representing multiple genera and families. Field and transplant house sampling of tomato and other vegetables by ourselves and collaborators has continued to confirm presence of GRSV in many peninsular Florida vegetable production areas. The closely related Tomato chlorotic spot virus (TCSV) has been identified multiple times in tomato field plants in multiple Florida counties suggesting that TCSV has become established in south Florida and make it important for us to continue to monitor tomato production for this newly detected relative of GRSV. Modifications have been made to GRSV detection protocols to allow for detection of TCSV in addition to GRSV and Tomato spotted wilt virus (TSWV), another related virus that is widespread in Florida. An experimental host range for TCSV has also been initiated to extend our previous work with GRSV. Weekly thrips counts and GRSV/TCSV incidence data from disease hotspots have been collected by collaborators. Field testing of updated AgScouter smartphone-based online scouting and decision support system continues to record thrips counts and GRSV/TCSV incidence. These data will be used to prepare distribution maps of thrips and GRSV/TCSV for subsequent analysis. This activity will continue each season through the conclusion of the project. Resistant and susceptible tomato cultivars for field tests have been identified from greenhouse host range testing and field surveys of different tomato cultivars for use in the 2013 fall growing season. Data collected show reduced incidence of TCSV in TSWV-resistant tomato. Multiple requests from growers and Extension personnel for GRSV and TCSV diagnosis and information have been responded to by us and collaborators throughout the year. Multiple grower, in-service training and scientific presentations have been made by ourselves and collaborators, and several popular press and Extension publications have been printed.