Field performance of wine grape rootstocks and fumigation during the establishment phase of a chardonnay vineyard in Washington

Authors: EAST, K - Michigan State University; Zasada, Inga; TARARA, J - Ste Michelle Estates; MOYER, M - Washington State University

Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2020
Publication Date: 4/1/2021
Citation: East, K.E., Zasada, I.A., Tarara, J., Moyer, M.M. 2021. Field performance of wine grape rootstocks and fumigation during the establishment phase of a chardonnay vineyard in Washington. American Journal of Enology and Viticulture. 72:113-125. https://doi.org/10.5344/ajev.2020.20023.
DOI: https://doi.org/10.5344/ajev.2020.20023

Interpretive Summary: Management of plant-parasitic nematodes, microscopic roundworms that feed on the roots of plants, in grape vineyard replant situations in Washington state is often approached by injecting a poisonous gas into the soil. An alternative nematode management strategy is needed. This study evaluated both the impact of nematodes on vine productivity and also the potential to use rootstocks (grafted plants) to manage nematodes. This publication reports on the first 3 years of data from a long-term experiment. It was found that rootstocks supported fewer nematodes compared to industry standard own-rooted vines. Additionally, own-rooted vines had lower productivity in the presence of nematodes compared to vines grown in soil with few nematodes. These results will be used by grape growers to select appropriate planting material when establishing a new vineyard.

Technical Abstract: Management of plant-parasitic nematodes in vineyard replant situations in Washington state is often approached with the use of preplant soil fumigation. The majority of wine grape acreage is planted to own-rooted Vitis vinifera, which is susceptible to the plant-parasitic nematodes Meloidogyne hapla and Xiphinema americanum (in the broad sense). Using resistant rootstocks to manage nematodes has not been evaluated in Washington vineyards. A long-term vineyard trial was established to evaluate the effects of soil fumigation and rootstock genotype on M. hapla and X. americanum population dynamics and vine growth during vineyard establishment (first three years). Vines in an existing V. vinifera ‘Chardonnay’ vineyard were first treated with foliar glyphosate. Randomized areas within the vineyard were then either fumigated or not with drip-applied metam sodium. Following fumigation, vines were removed in late fall 2014. In spring 2015, the vineyard was replanted to a Chardonnay scion on the following rootstocks: 1103 Paulsen, 101-14 Millardet et de Grasset, Teleki 5C, and Harmony. Self-grafted and own-rooted Chardonnay were included as controls. Fumigation reduced M. hapla soil second-stage juvenile (J2) population densities on own-rooted and self-grafted Chardonnay for only the first year after fumigation. One year after fumigation, the self-grafted and own-rooted vines had higher population densities of M. hapla J2 than rootstocks. However, all rootstocks supported measurable densities of M. hapla J2, which increased over time, indicating that these rootstocks were hosts for M. hapla, though poor hosts relative to V. vinifera. Fumigation was very effective in reducing population densities of X. americanum with few nematodes recovered up to 3.5 years after fumigation. As expected from the rootstock genotypes, none were resistant to X. americanum. Vines grown in fumigated areas had lower pruning weights through year 2, but not in year 3. By year 3, all rootstocks had higher pruning weights than own-rooted vines. There was no difference in yield between fumigation treatments, but yield in year 3 differed between rootstocks by 2.25 tonnes per hectare (1 ton per acre). After three years of vineyard establishment, the use of fumigation did not appear to have a measurable impact on vine health, and the use of rootstocks appeared to have a longer-term influence on vine vigor when grown in the presence of M. hapla.