Field day: Use of Protective Covers to Reduce Fungicide Usages in (Organic) Wine Grape Production in Virginia
5 September 2018
1 – 4 pm
595 Laurel Grove Rd.
Winchester VA 22602
Mizuho Nita, Ph.D, Virginia Tech
The total acreage of certified organic grape production in the US has increased from 12,575 acres in 1995 to 38,664 acres in 2011. However, only three Virginia vineyards have been approved by the USDA for their organic management practices for wine grape production, and only two have a winery as of 2018. The main reason why organic wine grape production is not common in VA or any other states located the east of Rockies is fungal diseases, which are driven by frequent rain events during summer months. Thus, the Nita lab has established two experimental vineyards with financial aid from the USDA/NIFA VDACS Specialty Crop Research Initiative Block Grant in 2012. Although we identified several cultivars that may do well with the organic practice, there are two significant challenges: a disease called black rot, which none of the OMRI-certified chemicals works sufficiently, and a potential loss of copper fungicides due to a trend of tighter regulations in other countries.
Rather than searching for other chemical components, which is usually in the hands of chemical companies, we proposed to the USDA’s Southern Region Sustainable Agriculture Research and Extension (SARE) on-farm grant to examine the efficacy of various paper bags or umbrella to individually protect grape clusters (grant ID: OS17-107). These bags and umbrellas are made out of water-resistant paper, designed to fit grape cluster, easily applicable with an embedded wire, with small holes for ventilation and water drain, and expected to last for a whole season.
Based on 2017 data, the bagging practice significantly reduced disease incidence and severity of black rot. Also, it showed that the earlier the timing of bagging, the better the result. Although application will be very labor intensive, a conversation with our farmer cooperator, Mr. Hambsch at Loving Cup Vineyards, revealed an extremely high cost of intensive removal of disease berries is necessary for his production. Thus, this method can be a good alternative method to reduce the intensity of the diseases. Although we tested out the bagging for the organic practice, it can be used for the conventional grape growing, especially if you are concerned about disease and fungicide residues on berries.
In this field day, I would like to invite you to visit our experimental plots in the AHS AREC to see these bags in action and discuss our findings.