- Fruits: grapes
- Crop Production: crop improvement and selection
- Education and Training: demonstration
- Pest Management: integrated pest management
Washington State is the second-largest wine grape producing region in the United States, with nearly 60,000 acres of “self-rooted” Vitis vinifera in the Columbia Valley. Contrarily, wine grapes worldwide have been produced using vinifera grafted onto rootstocks tolerant of devastating soilborne pests, such as phylloxera (Daktulosphaira vitifoliae) and parasitic nematodes, as well as to mitigate abiotic stressors.
Washington vineyards were first established in land mostly absent of significant populations of phylloxera and nematodes. The next greatest production challenge defaulted to cold injury; vinifera are more cold-sensitive than rootstock varieties. If a self-rooted vine is injured, new growth from the trunk and root system is retrained back to the trellis. If the scion of a grafted vine is injured, the healthy rootstock either needs to be regrafted or replanted, incurring costs that historically outweigh the benefits.
Parasitic nematodes have since established, and in 2019 and 2020, significant pockets of phylloxera were discovered across Columbia Valley vineyards. The only management solution for phylloxera is rootstock use. However, limited knowledge of rootstock characteristics in the Columbia Valley has caused a risk barrier in selection and adoption among producers. This project aims to “take the plunge” by planting a grafted demonstration vineyard where stakeholders can see and learn about establishing, growing and thriving with rootstocks. Through our results, which will be presented at industry field days, meetings and media outlets, producers will be prepared with applicable knowledge on how to select rootstocks for sustainable future wine grape production in the Columbia Valley.
Project objectives from proposal:
- Evaluate different grapevine rootstock cultivars to determine which have the most promise for Washington wine grape producers in terms of growth, nutrient, and hardiness characteristics. (Years 1- 3).
- Determine how different rootstock cultivars influence scion fruit characteristics, such as cluster weights, berry size, brix, titratable acidity (TA) and pH. (Year 3).
- Develop demonstration trials and deliver rootstock evaluation results to wine grape producers to promote rootstock adoption for sustainable future vineyard plantings (Years 2-3).