Read more about the article Fungal microbiome associated with grapevine trunk diseases in Oregon vineyards

Fungal microbiome associated with grapevine trunk diseases in Oregon vineyards

Grapevine trunk disease (GTD) is a disease complex that consists of the largest group of fungal pathogens causing disease and progressive vine decline. Due to the complex nature of GTD pathogens, understanding the disease as a phenomenon of single species or multiple species infection is always challenging. In addition, the environmental variables play a greater role in the dominance of one species over another. It is important to understand the species that are predominant in a region and their causal role in GTD development so that targeted disease management programs can be developed. In this research project, we study the diversity of GTD pathogens in grapevines of Northern and Southern Oregon; as well as to compare the different disease management practices including vineyard floor management and pruning wound protection.

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Read more about the article Differentiation and detection of blueberry scorch strains

Differentiation and detection of blueberry scorch strains

The Blueberry scorch virus (BlScV) was first identified in Oregon and Washington in 1987, and later in British Columbia in 2000. It has been found in over 140 blueberry fields in British Columbia. BlScV isolates exhibit a wide range of sequence diversity, with the 'Northwest' strains showing similar diversity to all blueberry scorch virus isolates. Cranberries have been identified as a host of BlScV, with infected bogs found in British Columbia, Washington, and Oregon. In British Columbia, the close proximity of cranberry and blueberry crops allows for efficient transmission of the virus. However, in Oregon and Washington, where cranberries are grown far from major blueberry production areas, transmission by aphids from cranberry to blueberry is limited. Efforts are being made to identify and remove infected bushes and implement control measures to eliminate the virus from affected fields in Oregon and Washington. The diverse strains of blueberry scorch virus make tracking and eradicating the virus challenging. Research efforts are underway to establish a reliable detection method and compare the 'Northwest' strain of the virus with more severe strains found in the northeastern U.S. and British Columbia. This research aimed to investigate the potential for eradicating BlScV from infected fields in Oregon and Washington.

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Read more about the article Risk assessment of nematode-transmitted viruses of small fruit crops in the Pacific Northwest

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

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.

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

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.

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Read more about the article Botrytis Bunch Rot: Where, When, and What to use

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

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.

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