Grape (Wine & Juice Viticulture) Archives - Page 2 of 5

The effect of soil parameters on plant-parasitic nematodes of wine grapes in Washington and Oregon

Post author:Abby Clayton-Gearing
Post published:March 5, 2024
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Plant parasitic nematodes are costly pests that cause global crop loss of over $100 billion dollars. Previously it was thought that the large populations of ring nematode in Oregon and Northern root-knot nematode in Washington vineyards were caused by differences in soil characteristics. It was found that soil texture had no influence on both types of nematode population growth. It was found that Northern root-knot nematodes that live inside of the roots thrived in acidic (low pH) soil more than alkaline (high pH) soil. It was found that soil pH had no effect on ring nematodes that live outside of the roots. Also generated was a computer model to automate nematode egg counting. These results will help generate parasitism risk maps, helping wine grape growers make better vineyard planting decisions, and will increase the speed with which scientists can identify plant parasitic nematode eggs.

Risk assessment of nematode-transmitted viruses of small fruit crops in the Pacific Northwest

Post author:Abby Clayton-Gearing
Post published:February 25, 2024
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The Pacific Northwest (PNW) maintains a $840 million small fruit industry susceptible to nepoviruses, which are viruses that are transmitted by dagger nematodes. The association of viruses with nematodes is complicated with many nepoviruses, taxonomic confusion among vector nematodes, and limited data on the ability of Xiphinema spp. populations to vector many of the nepoviruses. Research was conducted to provide an up-to- date assessment of the problem in the region and to develop new molecular tools to improve detection of this disease complex. Over two years, 96 small fruit fields and vineyards were sampled in the PNW. In total 43 vineyard, 24 blueberry, 15 raspberry, 8 blackberry, 5 strawberry and one ribes fields were assessed for dagger nematode and nepoviruses. The highest incidence of dagger nematode was found in grape vines (79 %) followed by raspberry and blueberries. The population densities were 56 and 37 nematodes per 250 cc of soil in grapes and blueberry, respectively. Tomato ringspot virus (ToRSV) was found in three blueberry fields, while, in grape, raspberry and ribes only one field each. Tobacco ringspot virus (TRSV) was found in six vineyards.

Read more about the article Inducement of malolactic fermentation using Lactobacillus plantarum in musts and wines from the Pacific Northwest.

Inducement of malolactic fermentation using Lactobacillus plantarum in musts and wines from the Pacific Northwest.

Post author:Abby Clayton-Gearing
Post published:February 21, 2024
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The completion of both alcoholic and malolactic fermentation (MLF) in red wine are essential to the quality and stability of red wine and to its commercial success in the market. In this study, alcoholic and malolactic fermentations were induced in low and high nitrogen-containing Cabernet Sauvignon musts by adding both yeast (Saccharomyces cerevisiae) and bacteria (Oenococcus oeni or Lactobacillus plantarum) at the same time. While O. oeni was able to complete MLF in the high nitrogen fermentations, only one of the three strains of Lb. plantarum was able to convert the majority of malic acid to lactic acid (<0.5 g/L residual malic acid). Under low nitrogen conditions, neither alcoholic or malolactic fermentation finished in any of the wines. Subsequent fermentations using a synthetic grape juice medium yielded poor growth of bacteria whether inoculated subsequently or concurrently with S. cerevisiae. Additional studies with Lb. plantarum are required to fully evaluate their potential usefulness to Pacific Northwest winemakers.

Botrytis Bunch Rot: Where, When, and What to use

Post author:Abby Clayton-Gearing
Post published:February 15, 2024
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From 2020-2022, eleven sites from nine different vineyards in Oregon, and four in Washington were surveyed for Botrytis by sampling grape inflorescence and developing fruits, vineyard floor debris (prior year grape rachis), and nuisance blackberries. Botrytis on grape inflorescence and fruits varied from site to site and year to year likely due to yearly disease pressure differences and unique site microclimates. Prior year dead grape rachis on the vineyard floor with sporulating Botrytis infestations varied from year to year as well, but generally declined as the season progressed. Incidence of Botrytis on vineyard floor debris in all but one site in 2021 was over 75% in late April and all sites sampled decreased over time to under 25% by September. Wild nuisance blackberry flowers and fruits adjacent to the vineyard were also found to be potential sources of Botrytis inoculum throughout the season. Inoculum estimation from historical spore trap DNA samples originally taken to monitor powdery mildew in the Willamette Valley were re- assayed for Botrytis inoculum.

Epidemiology and Management of Plant-parasitic Nematodes in Winegrapes

Post author:Abby Clayton-Gearing
Post published:February 2, 2024
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Nematodes are root feeding organisms that can cause direct damage and can also be a virus vector. Nematodes can severely limit the successful establishment of vines and vineyards and impact production yields by 5-20%. There are several products available to growers to assist in managing Nematode populations and increase successful vine establishment. This research evaluates combinations of synthetic (at half the recommended commercial rate) and biological nematicides to reduce populations of plant-parasitic nematodes, and increase populations of free-living beneficial nematodes and to increase vine productivity.