Identification of Grapevine Trunk Diseases in Virginia and Implementation of Control Strategies.

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1 Identification of Grapevine Trunk Diseases in Virginia and Implementation of Control Strategies

2 Grapevine Trunk Diseases Worldwide diseases Fungal diseases (Ascomycetes) Economic impact -$260 million per annum Decrease longevity of vineyards Decrease in yield and quality of grapes Increase management costs Net income = Revenue (yield x grape market price) Total Expenses

3 Causal Agent(s):. Eutypa lata. Diatrypaceae fungi Eutypa Dieback Symptoms:. Wedge canker. Stunted shoots, small chlorotic cupped leaves.poor fruit set

4 Bot Canker Causal Agent(s):. Botryosphaeria species Symptoms:. Wedge canker. No foliar symptoms. Fruit symptoms with some Botryosphaeria species

5 Esca Causal Agent(s):. Phaeoacremonium species. Phaeomoniella chlamydospora. Cadophora species Symptoms:. Black spots, gumming, streaking in wood. Tiger-stripe pattern on leaveses. Necrotic spots on berries

6 Causal Agent(s): Young Esca. Phaeoacremonium species. Phaeomoniella chlamydospora Symptoms:. Black spots, gumming, streaking in wood. Chlorotic leaveses. Decline of young grapevines

7 Diseases in old plants vs. young gplants Diseases identified in nursery plants Esca Bot canker Others? Diseases identified in grapevines Eutypa Esca Bot canker Others Net income = Revenue (yield x grape market price) Total Expenses

8 Identification of Grapevine Trunk Diseases in Virginia Virginia Vineyard and Winery Market Analysis Year Tons Produced $ per Ton Planted Acres ,000 $1,530 2, ,600 $1,300 1,900 Sampling Size 6vineyards 92 wood samples pe 6grape varieties ranging from 1to 30 years-old Merlot, Cabernet Sauvignon, Vidal, Pinot Grigio, Sauvignon Blanc, Chardonnay

9 Identification of Grapevine Trunk Diseases in Virginia

10 11 U.S. states & and 2 provinces of Canada 50 vineyards 700 wood samples 30 grapevine varieties including Vitis vinifera, Vitis species and inter-specific hybrids

11 Distribution of Grapevine Trunk Diseases in Northeastern United States

12 Distribution of Grapevine Trunk Diseases in Northeastern United States

13 Mendocino Colusa Yolo Sonoma Napa Sacramento El Dorado Amador Solano Marin San Joaquin Stanislaus Santa Merced Clara Madera Fresno San Benito Tulare Monterey B. australis dothidea B. L. theobromae dothidea B. N. lutea australe N. B. obtusa luteum N. B. parva parvum D. B. rhodina seriata B. D. stevensii mutila D. B. viticola corticola ii l B. D. iberica viticola D. iberica Distribution of Bot Canker and Eutypa Dieback in California San Luis Obispo Kern Santa Barbara Riverside

14 Factors Affecting Disease Distribution Landscape Vineyard Ecology Weather Varieties planted Viticultural practices Factors inherent in the disease

15 Disease Management. Start with clean plants. Do not stress grapevines after planting 15

16 Disease Cycle Spores Wind Rain Wounds Fruiting Bodies Decay

17 DISEASE MANAGENT REMOVE INOCULUM 17

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20 DISEASE MANAGENT - PRUNE IN DRY WEATHER 20

21 DISEASE MANAGENT DOUBLE PRUNING One mechanical pruning after harvest One hand pruning before bud break 21

22 DISEASE MANAGENT PROTECT WOUNDS Mechanical Frost Pruning 22

23 Field Evaluation of Fungicides Percent infection of pruning wounds treated with 4 selected fungicides 23

24 Field Evaluation of Fungicides Percent infection of pruning wounds treated with 4 selected fungicides 24

25 DISEASE MANAGENT PROTECT WOUNDS Use of Biofungicides Bioworks Inc. Trichoderma harzianum Bio-agent can be sprayed on pruning wound surfaces. Natural Industries Streptomyces lydicus Bio-agent will last for the entire period of pruning wound susceptibility No soil contamination Agraquest Inc. Bacillus subtilis 25

26 Conclusions The main trunk disease in Virginia is Esca. In northeastern US vineyards, there is a high diversity of fungal taxa associated with grapevine trunk diseases. Some fungal taxa are similar as the ones found in Mediterranean climates but some taxa are also unique. The geographical distribution of some of these fungi can be specific or broad. To control these diseases, plant clean material to start a vineyard, use sanitation and cultural practices and protect wounds. 26

27 Acknowledgements USDA - Crops at Risk Kendra Baumgartner (UC Davis), Wayne Wilcox (Cornell University) Tony Wolf, Mizuho Nita (Virginia Tech) Extension specialists, growers, consultants, vineyard owners, etc 27

28 Questions? Q 28