Location: Crops Pathology and Genetics Research
Project Number: 2032-22000-015-29-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2013
End Date: Aug 31, 2015
1. Identify leafhopper vectors in Napa Valley involved in the transmission of GRBaV and establish transmission characteristics. 2. Determine reservoirs of the leafhopper vectors and GRBaV in the vineyards. 3. Localize virus in insect and plant tissues.
Collect leafhoppers on grapevines that exhibited red blotch disease symptoms and tested positive for GRBaV and grapevines with green canopy that tested negative for GRBaV during surveys conducted in fall 2012. Release adults and nymphs onto healthy grapevines (tested to be free from GRBaV) and establish leafhopper colonies. Collect adults and nymphs reared on GRBaV-free grapevines, starve them for 1 hour and release them onto GRBaV-infected grapevines. Monitor the grapevines for GRBaV infection by PCR tests. Once a vector is confirmed, conduct surveys in vineyards to locate alternate hosts. Examine the weeds prevalent in the vineyards and plants present in adjacent riparian areas to determine foraging activity of the insect vector and test these hosts for GRBaV infection. Produce antibodies for synthetic oligopeptides derived from the predicted amino acid sequences of the GRBaV capsid protein and conduct immunosorbent electron microscopy (ISEM) for GRBaV on fixed thin sections of insect vectors and plant tissues. Finally, using this information, initial disease management recommendations will be generated and distributed to growers, nursery managers and pest control advisers.