A scenic trip looking at the luscious green leaves and breathtaking views of California’s wine grape growing regions is an incredible experience. However, the hidden truth remains that many of these grapevines are infected with a disease that reveals its presence during or after véraison (a transitory stage that represents the onset of berry ripening). In case of red wine grape cultivars, the green leaves seen before véraison (Picture A) might transition into red colored leaves after véraison (Picture B). This reddish-purple discoloration observed on grape leaves are the symptoms produced as a result of virus infection.
Virus diseases are a major concern to the wine grape production in California and around the world. A survey of major California wine grape-growing regions (Napa, Sonoma and Northern San Joaquin Valley) has estimated an economic loss of $29,902 to $226,405 per hectare in leafroll disease infected Cabernet Sauvignon vineyards (Ricketts et al., 2015. Am. J. Enol. Vitic. 66:138-147).
Owing to the debilitating effects of these diseases on wine grape production, identifying the causal agent, preventing the disease and minimizing its spread is of utmost importance in order to reduce the economic losses caused by these diseases. Sunburst Plant Disease Clinic Inc. works towards this goal; offering diagnostic services to various grapevine diseases caused by virus, bacteria, fungi, phytoplasma and other pathogens. Besides having diagnostic tests for bacteria, fungi and phytoplasma, we also have diagnostic tests for Grapevine leafroll disease, Grapevine red blotch disease, Rugose wood complex, Fan leaf degeneration/decline, Pierce’s disease, Crown gall, Grapevine fleck virus, Grapevine virus A (GVA), GVB, GVD, Tomato ringspot virus, Tobacco ringspot virus, Arabis mosaic virus and recently reported Grapevine Syrah virus.
Our complete “360 Approach” includes identifying the causal agent at Sunburst Plant Disease Clinic Inc. and developing a remedial program with Fusion 360, Inc. our sister company that provides nutrient products, which are renowned for achieving incredible results; not only by increasing the yield and quality, but by increasing the overall plant health, thereby managing the disease by promoting pathogen resistance. In case of virus diseases, ‘Prevention is better than cure’. With our “360 Approach” we will be able to prevent the future infection and the disease spread as well as minimize the economic loss caused by the disease. Proven results in many cases has shown that this approach has placed the pathogen into remission, thereby allowing the grower to secure an excellent crop with excellent wine quality.
We also perform complete vineyard inspections; work closely with growers towards identifying the problem, collecting proper samples and coming up with a solution to improve overall sustainability of the vineyard.
For further details regarding pricing and testing specifics, please contact our office and lab personnel at (209) 667-4442. Visit us at www.sunburstpdcinc.com