For 2019-2020, the OWB allocated $417,000 for the support of these research grants. Below are the nine funded projects. Updates on these projects will be reported throughout the year.


Laurent Deluc, Associate Professor, Department of Horticulture, Oregon State University.
Determining the role of Auxin-Response Factor 4 in the timing of ripening initiation in Vitis vinifera

Control of the timing of ripening of wine grapes is an important research topic for the wine industry. We are working on one potential protein candidate (Auxin Response Factor 4) that may impact when grape berries enter the ripening. Using genetic engineering we want to determine if the activity of ARF4 can affect the length of ripening to maturity. The genetic characterization of the ripening initiation is of great importance to the development of innovative practices in the field aimed at advancing or delaying the fruit ripening process in order to withstand rapidly evolving climatic conditions.


Achala KC, Plant pathologist and Assistant Professor, Department of Botany and Plant Pathology and Southern Oregon Research and Extension Center, Oregon State University
Grapevine trunk diseases in Oregon vineyards: A pilot project on epidemiology and management

A pilot project on epidemiology and management of Grapevine Trunk Diseases (GTDs) will be initiated in Oregon vineyards. The trunk disease management in Oregon mostly relies on information generated in neighboring states. However, the epidemiology of every GTD is influenced by regional climatic conditions. At the end of this project we hope to understand the most common type of GTDs in two distinct wine grape growing regions in Oregon and their seasonal development as affected by weather variables in these regions. With this study we expect that the Oregon wine industry will benefit from having local-level information on GTDs and addressing management practices accordingly.


Walt Mahaffee, Research Plant Pathologist USDA-ARS-HCRL
Persistence of fungicide resistance in grape powdery mildew

This research will determine if resistance to strobilurin fungicides impact the growth rate, germination, sporulation of grape powdery mildew in relation to the temperature and UV exposure.  These results will allow us to determine how long after ceasing strobilurin use in a vineyard the genetic resistance will persist is vineyards and when it will be suitable to begin using strobilurins again. It will also aid in the development of resistant mitigation strategies for other fungicides in the future.


Marcelo Moretti, Assistant Professor, Department of Horticulture, Oregon State University
Moving away from herbicides and towards sustainable vineyard weed management

There has been increased consumer interest on the environmental and human health risks associated with herbicides. Non-chemical weed control alternatives have mostly been studied in vineyard alleyways. This project will evaluate the impacts of under-vine cover crops, cultivation, and mowing on soil moisture, weed control, vine vigor, and crop quality. In a second study, a range of cover crop species will be evaluated for weed suppression, persistence, and potential resource competition with the vine. We aim to answer if growers are better off tilling or mowing under the vine, and what plant species are better suited for under-vine cover crops.


James P. Osborne. Extension Enologist, Department of Food Science and Technology, Oregon State University
Utilizing malolactic fermentation as a tool to prevent Brettanomyces bruxellensis wine spoilage

B. bruxellensis causes wine spoilage through the production of horsey or barnyard-like smelling volatile compounds. During and shortly after malolactic fermentation (MLF), wine is particularly susceptible to Brettanomyces since sulfur dioxide (SO2) cannot be added until MLF is complete. Because of this, it is recommended to conduct a rapid MLF with inoculated cultures to minimize the time that wine is without SO2 protection. This project investigates an additional benefit of conducting a rapid MLF: the prevention of B. bruxellensis growth due to inhibitory interactions with O. oeni. This information will aid in the development of strategies to better utilize MLF to reduce the risk of wine spoilage by B. bruxellensis.


Michael Qian, Professor, Department of Food Science and Technology, Oregon State University
Identification of smoke odorants by gas chromatography/olfactometry and assessment of smoke odorants in grapes and wine

Smoke taint has become a serious concern for the wine industry, particularly in Southern Oregon. Smoke taint is an off-aroma describing the wine with smoky, medicinal, and ashy characters, and this unpleasant taint is caused by grapes or grapevine exposed to bushfire smoke before grape harvest. Various chemical compounds such as guaiacol, 4-methylguaiacol, and cresols have been identified to be correlated or contribute to the smoke taint, but the actual root cause(s) of smoke taint in wine has not been fully understood. The project for the first year will systematically investigate the characteristic compounds responsible for smoke taint in wines using gas chromatography-mass spectrometry-olfactometry technique.


Patricia Skinkis, Professor and Viticulture Extension Specialist, Oregon State University
Characterizing Willamette Valley soil moisture and grapevine response under drying seasonal conditions

Prior research shows that vineyards experience late season water stress that may be limiting vine growth and production in the Willamette Valley, depending on soil type and season. There is a need for producers to understand how to manage vineyard soil water, whether through irrigation or vineyard floor management. Through this project, we will conduct a three-year study to monitor the effects of soil moisture on Pinot noir grapevine growth, water stress, and fruit impacts across three soil types that are common to Willamette Valley wine grape vineyards. This work will help inform future research into soil moisture management that will advance our vine balance guidelines based on soil and productivity potential.


Vaughn Walton, Professor and Horticultural Entomologist, Oregon State University
Improved understanding of virus transmission and management of key vector(s) associated with Grapevine Red Blotch Virus

Grapevine red blotch virus (GRBV) is the causal agent of grapevine red blotch disease affecting wine grape production in Oregon and California. The three-cornered alfalfa hopper Spissistilus festinus (Hemiptera: Membracidae) was shown to vector GRBV under greenhouse conditions in California. While S. festinus was found in low numbers in certain wine grape production regions of Oregon, its apparent absence in areas where GRBV appears to be spreading suggested that one or more related treehopper species may vector the virus in different geographical regions. The goals of this proposal are to: 1. determine virus status of plants subjected to transmission biology assays from 2016-2018; 2. conduct refined transmission biology trials; 3. evaluate conventional and cultural control strategies of key treehopper species; and 4. evaluate behavioral management techniques for key treehopper species.


Jeremy B. Weisz, Associate Professor of Biology, Linfield College
Terroir and Microbiomes: Examining the impacts of environmental variations and farming practices on wine grape microbiomes

The wine grape microbiome, the community of bacteria, yeast, and other microbes living on them, is important in the vinification process. Any microbe that is on the grape may end up in the fermentation, which may influence the progression of this process. This research continues to investigate how differences in geography and farming practices influence the microbiome of grapes, leading to a specific microbial terroir. Building on previous work, we are expanding the scope of our study to include vineyards throughout the state and to track microbiomes through the vinification process. Vineyard managers and winemakers can use the results from this project to help make decisions about how terroir and its management influence the microbiome and the resulting wine.