Reducing leaf chlorosis of ‘Concord’ vines: Effects of FeEDDHA and rootstocks

‘Concord’ vineyards in central Washington are plagued by a leaf chlorosis problem that occurs around bloom. It significantly reduces vine size, vine uniformity, and productivity, and even causes vine death. Chlorotic leaves from WA vineyards have significantly lower active Iron (Fe) compared with green leaves whereas total leaf Fe is the same or even higher; 2) high soil pH induces leaf chlorosis in Concord vines; 3) leaf active Fe content is a better indicator of Concord vine Fe status than total Fe. This project is a continuation of the work. The objectives were to determine the effects of FeEDDHA (a chelated form of Fe) and different rootstocks on reducing leaf chlorosis. A field trial in central WA over 3 years clearly showed that FeEDDHA application significantly decreased the degree of canopy leaf chlorosis; and that Concord vines grafted onto 3309, 5C and 110R had better growth, higher photosynthesis, and less chlorosis than the own-rooted vines at high soil pH (7.6).

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Developing a Spray-Induced Gene Silencing (SIGS) method for the control of Grape Powdery Mildew (Erysiphe necator)

Powdery Mildew development in vineyards in the Pacific Northwest is one of the greatest impacts to grape and wine quality and the economic health of a grape grower is severely impacted by the number of sprays required to control the disease or loss in fruit sales if a severe infection develops. In high wine-producing regions, Grape Powdery Mildew (GPM) accounts for 75% of total pesticide use applications. If the grapevines are not properly treated until harvest, the presence of GPM in harvest grape clusters substantially depreciates the value of the entire crop. This project aims to develop a methodology to turn off specific grapevine genes (susceptibility genes [MLO]) and Powdery Mildew-related genes essential for the pathogen’s life cycle.

Continue ReadingDeveloping a Spray-Induced Gene Silencing (SIGS) method for the control of Grape Powdery Mildew (Erysiphe necator)

Epidemiology and Management of Plant-parasitic Nematodes in Winegrapes

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.

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Attraction and retention of beneficial insects through enhanced plant biodiversity in irrigated vineyards (Vitis vinifera L.)

The success of both integrated pest management and organic production is critically dependent on naturally occurring insect biological control agents. Numerous studies (including some in vineyard systems) have indicated that populations of beneficial insects can be increased by increasing plant diversity (e.g., through cover cropping). Research targeted specifically at the situation in eastern Washington irrigated vineyards is therefore urgently needed.

Continue ReadingAttraction and retention of beneficial insects through enhanced plant biodiversity in irrigated vineyards (Vitis vinifera L.)