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.

Continue ReadingEpidemiology and Management of Plant-parasitic Nematodes in Winegrapes

Evaluating Commercially Available Technologies for Weed Management in Blueberries: Saturated Steam and Rotary Brush

Washington and Oregon account for 85% of national raspberry production and 15% of worldwide production. Growers from Washington and Oregon harvest over 80 million pounds of raspberries on about 12,000 acres. Tomato ringspot virus (ToRSV) continues to be a problem in raspberry production in the Willamette Valley in Oregon, and in southern Washington. The predominant mode of spread of ToRSV is via the nematode vector Xiphinema americanum, also known as “Dagger” nematodes. Methyl bromide is often a method of choice for managing ToRSV and other nematode-borne plant viruses because it kills the nematode vectors. However, ToRSV often reappears within 3-4 years of fumigation with methyl bromide.

Continue ReadingEvaluating Commercially Available Technologies for Weed Management in Blueberries: Saturated Steam and Rotary Brush

Detection and monitoring of Tomato Ringspot Virus in red raspberry and Xiphinema americanum.

Washington and Oregon account for 85% of national raspberry production and 15% of worldwide production. Growers from Washington and Oregon harvest over 80 million pounds of raspberries on about 12,000 acres. Tomato ringspot virus (ToRSV) continues to be a problem in raspberry production in the Willamette Valley in Oregon, and in southern Washington. The predominant mode of spread of ToRSV is via the nematode vector Xiphinema americanum, also known as “Dagger” nematodes. Methyl bromide is often a method of choice for managing ToRSV and other nematode-borne plant viruses because it kills the nematode vectors. However, ToRSV often reappears within 3-4 years of fumigation with methyl bromide.

Continue ReadingDetection and monitoring of Tomato Ringspot Virus in red raspberry and Xiphinema americanum.

Heat stress in wine grapes: acclimation and potential mitigation

Heat stress poses challenges for the sustainable production of premium wine grapes in the Pacific Northwest. The intensity of heat waves has been increasing. For example, the series of heat wave events in 2021 broke temperature records in many locations in this region, and heat waves were again common during the 2022 and 2023 growing season. Growers need knowledge of how grapevines adjust to heat waves or sudden temperature changes to make informed management decisions. We grew potted grapevines in environmentally controlled growth chambers under different temperature regimes (simulating cool and warm growing seasons) before exposing the vines to sudden temperature changes with maximum temperatures varying from 77°F to 104°F. Photosynthesis measurements showed that grapevines might tolerate a sudden rise in temperature better in a warm than a cool season. During extended heat waves, however, the cool season-acclimated vines recovered faster than the warm season-acclimated vines.

Continue ReadingHeat stress in wine grapes: acclimation and potential mitigation