Plant-pathogenic nematodes that cause yield loss in California and European vineyards are found in over 85% of Oregon vineyards. Population densities of Xiphinema americanum (dagger nematode) and Criconemella xenoplax (ring nematode) were found in 37% of vineyards at levels reported to cause 10-25% loss in California vineyards. However, these nematode...
The introduction of new clones and rootstock varieties has played an important role in the development of the Oregon wine grape industry. The OSU Grapevine Mother Block has been an integral part of this overall vine improvement program providing a readily accessible source of specific pathogen tested grapevine plant material...
Pinot noir and Chardonnay are the two main winegrape varieties in Oregon. In 1998, they comprised approximately 59% of the Oregon winegrape acreage, and 57% of the total production for a value of $10,803,000 (62% of total) (1). Internationally, clonal selection of Pinot noir and Chardonnay have made available, for...
Most quality wines are produced in areas where annual precipitation is below 700 to 800 mm (Jackson & Schuster, 1994), and evidence suggests that high rainfall or excessive irrigation lowers quality. Excessive irrigation is reported to slow ripening, increase yields partially berry enlargement, elevate juice pH and acid content, and...
With new vineyard planting and the replanting of older vineyards on phylloxera-resistant rootstock on the rise, grape growers are looking for rootstocks that are good fits for a particular site and management style. Making an informed decision on rootstocks before planting can help create a vineyard that will be manageable...
The wine grape industry is rapidly growing in Oregon. By the year 2005, we could predict that Oregon will have over 10,000 acres in wine grape production. At a meeting last year, the Grapevine Improvement Committee acknowledged that little was known about the presence of potential pest and beneficial insects...
To provide educational programming in support of the Oregon winegrape industry through delivery of educational seminars, newsletters, the Northwest Berry & Grape Information Net, Extension publications, site visits, and telephone consultations.
Traditionally, winemakers have relied upon 'spontaneous' malolactic fermentation (MLF) from indigenous species which may take weeks or months to go to completion depending upon the wine and the cellar conditions. Control of MLF has increased with the development of pure MLF bacterial starter cultures. Pure cultures started from slants generally...
Increasing ecological awareness led to the conceptualization and implementation of sustainable production systems such as Integrated Production. Integrated Production (IP) aims at achieving optimum yields of high quality fruit utilizing environmentally safe procedures. Priority is given to the utilization and enhancement of natural regulating processes and to the reduction of...
RESEARCH OBJECTIVES:
1. Determine differences in microbial community structure and microbial biomass among Oregon vineyard soils using phospholipid fatty acid (PLFA) analysis.
2. Assess the relative importance of several environmental factors affecting microbial community structure in Oregon vineyard soils.
3. Test the ability of PLFA analysis to distinguish differences in...
Stuck and slow fermentations are a major concern of winemakers. If the levels of fermentable nitrogen in juice are too low, fermentations will be slower and may stop or 'stick' before all the fermentable sugar is utilized by the yeast. Sluggish and stuck fermentations are also sometimes accompanied by production...
Several macerating pectinase enzyme preparations are currently being used by Oregon wineries to enhance color, color stability and phenolic extraction of red wines. Previous research on the use of commercial pectinase enzymes in Oregon Pinot noir and Cabernet Sauvignon wines showed that some enzyme preparations were capable of reducing red...
A broad range of factors influence wine grape quality and manipulation of these factors has stimulated interest among grape growers, wine makers, and research scientists alike. One such factor affecting wine grape quality is crop level, particularly for Pinot noir. Since the capacity of a vine to ripen fruit depends...
Agrobacterium vitis is a bacterium that causes crown gall in grapevines. Plant injury from freezing temperatures or mechanical damage during cultivation often provide wounds required for infection to occur. Crown gall may kill grapevines and a new shoot is often brought up from the root to replace dead vines. Discovery...
The introduction of new clones and rootstock varieties has played an important role in the development of the Oregon wine grape industry. The OSU Grapevine Mother Block has been an integral part of this overall vine improvement program providing a readily accessible source of specific pathogen tested grapevine plant material...
Develop a cost-effective system for identifying potential biological control agents of powdery mildew on grape that are efficacious in the Pacific Northwest. 2. Begin a primary screening program to develop biological control agents specifically adapted to the Pacific Northwest.
Soil and vineyard vegetation management are tools that may be used to create stable growing conditions for the grapevine roots and to preserve soil fertility for high grape quality in future years. The use of cover crops is commonly practiced in viticultural areas where precipitation exceeds 600-700 min (24-28 in)...
Three forecasting programs for scheduling fungicide applications were selected for comparison with the standard Oregon phenology based program. The California (Gubler-Thomas, UC-Davis) program used leaf wetness and temperature early in the year to predict ascospore infection periods and only temperature during the summer to predict conidial infection periods. The New...
To provide educational programming in support of the Oregon winegrape industry through delivery of educational seminars, newsletters, the Northwest Berry & Grape InfoNet, Extension publications, site visits, and telephone consultations.
Five different trellis and training systems were compared in their effect on yield components, fruit composition, fruit set, and shoot morphology in Pinot noir grapevines in 1996 and 1997. This trial was performed on established vines planted on a low-vigor valley floor site, in the Willamette Valley of Oregon. The...
For this trial, established Pinot noir vines, located on the valley floor of the Umpqua Valley in Oregon were used. In 1996 and 1997 sixteen vines trained to the Scott Henry trellising system were separated into four different quadrants, determined by shoot orientation: Bottom canopy, shoots trained toward the ground;...
Pinot noir and Chardonnay are the two main winegrape varieties in Oregon. In 1997, they comprised approximately 58% of the Oregon winegrape acreage, and 60% of the total production for a value of $14,171,000 (66% of total) (1). Internationally, clonal selection of Pinot noir and Chardonnay have made available, for...
It is anticipated that at least one additional clone (Merlot 347) will be added when it becomes available in 1999. All clones are being propagated on 101-14 rootstock. Plots will be located in 5 vineyards from Ashland to the Applegate Valley. Each vineyard will have 20 vines of each clone,...
Five different trellis and training systems were compared in their effect on yield components, fruit composition, fruit set, and shoot morphology in Pinot noir grapevines in 1996 and 1997. This trial was performed on established vines planted on a low-vigor valley floor site, in the Willamette Valley of Oregon. The...
Plant-pathogenic nematodes that cause yield loss in California and European vineyards are found in over 85 % of Oregon vineyards. Population densities of Xiphinema americanun (dagger nematode) and Criconemella xenoplax (ring nematode) were found in 37% of vineyards at levels reported to cause > 10-25% loss in California vineyards. However,...
Crown gall can develop on grapevines wounded by freezing temperatures, mechanical damage or grafting. Pathogenic agrobacteria residing within the vascular system are able to initiate tumor growth in damaged plant cells. Sampling from 21 sites in Oregon vineyards and nurseries yielded diverse populations of pathogenic agrobacteria. Most of the pathogenic...
Commercial fermentation practices have been evaluated for several vintages to determine their effects on anthocyanin and phenolic extraction, wine color intensity, color stability, and sensory characteristics of Oregon Pinot noir wines. Trials have included fermentation processing practices (1994), the use of different commercial yeast strains (1995 and 1996), the addition...
For this trial, established Pinot noir vines, located on the valley floor of the Umpqua Valley in Oregon
were used. In 1996 and 1997 sixteen vines trained to the Scott Henry trellising system were separated
into four different quadrants, determined by shoot orientation: Bottom canopy, shoots trained toward the
ground;...
OBJECTIVES:
To determine the effects of commercial enzyme and tannin additions on the appearance, aroma and flavor profiles of Pinot noir processing trials. The wines were made by Barney Watson as part of the experimental wine program at Oregon State University (see Fermentation Processing Effects of Anthocyanin and Phenolic Composition...
Degenerative diseases of aging such as cancer, cardiovascular disease, and brain dysfunction are increasingly found to have, in part, an oxidative origin. As a result, dietary antioxidants play a major role in minimizing this damage and preventing or delaying the pathophysiology. Population groups that generally do not smoke (a significant...
Over the last several years 'stuck' and 'sluggish' fermenations have become a ma or concern of winemakers in Oregon as well as in Washington and California. During the 1996 vintage we began a preliminary survey of Oregon musts and juices at harvest and showed that many were low or marginal...
The Northwest Berry & Grape InfoNet (NBGI) went online December 29, 1995, and since that time it has become an important information and communications resource for the winegrape industry of the Northwest. It was accessed more than 14,000 times during its first year, and it is routinely used by grape...
For over 14 years there has been a Area Horticultural Extension Agent available to assist winegrape growers in Jackson and Josephine Counties with production problems by conducting educational programs and applied research projects. While the salary for this position is paid by Oregon State University Extension, support funds which pay...
Survey data compiled in 1995 showed that plant-pathogenic nematodes that cause yield loss in California and European vineyards are found in over 85% of Oregon vineyards. In over 37% of the samples collected, population densities of Xiphinema wnericanwn (dagger nematode) and Criconenw1la xenoplax (ring nematode) were greater than levels known...
Three forecasting programs for scheduling fungicide applications were selected for comparison with the standard Oregon phenology based program. The UCDavis (California) program used leaf wetness and temperature early in the year and only temperature during the summer. The New York program was based on rainfall and temperature. The German Oi...
Pinot noir and Chardonnay are the two main varieties in Oregon. Together they comprise approximately 60% of the Oregon winegrape acreage, and 64% of the total production for a value of $10,482,000 (69%). Internationally, clonal selection of Pinot noir and Chardonnay have made available, for each variety, an array of...
Five replicated rootstock trials established in Oregon's three main viticultural regions were evaluated for the effect of rootstock on Pinot noir performance. All the trials except Alpine included the following seven rootstocks: ungrafted Pinot noir, 3309 Couderc, 101-14 Millardet et De Grasset, 44-53 Malegue, 420 A Millardet et De Grasset,...
Training descriptive analysis panels can be very costly, taking months to select and train panelists, develop descriptors and standards, and finally collect and analyze the data. Recently, the Oregon State University wine program has utilized industry winemakers to gather descriptive data on experimental wines. From 10-20 winemakers visit the university...
For over 14 years there has been a Area Horticultural Extension Agent available to assist winegrape growers in Jackson and Josephine Counties with production problems by conducting educational programs and applied research projects. While the salary for this position is paid by Oregon State University Extension, support funds winch pay...
The nng nematode, Cnconenwlla xenoplax, has been reported to depress the vigor and yields of grapevines in Europe, California, Washington, and Michigan. Population densities of 500 C. xenoplax per kg of soil have reported to reduce vine yield 10-25% in California. A survey of Oregon vineyards found C. xenoplax in...
Five different trellis and training systems were compared in their effect on yield components, fruit composition, fruit set, and shoot morphology in Pinot noir grapevines. The treatments were: upright vertical, cane pruned (Guyot); upright vertical, spur pruned (Bi-lateral Cordon); Scott Henry, cane pruned; Lyre, cane pruned; and Geneva Double Curtain...
Degenerative diseases of aging such as cancer, cardiovascular disease, and brain dysfunction are increasingly found to have, in part, an oxidative origin. As a result, dietary antioxidants such as Vitamins C and E and carotenoids play a major role in minimizing this damage and preventing or delaying the pathophysiology. Population...
Pinot noir vines, trained to the Scott Henry trellising system were separated into four different quadrants: Bottom canopy, trained toward the ground; Top canopy, trained upwards; East orientation, receiving the morning sunlight; and West orientation, receiving afternoon sunlight. Yield components and fruit composition were measured for each canopy, orientation, and...
Crown gall can develop on grapevines wounded by freezing temperatures, mechanical damage or grafting. Increased demand for grape varieties grafted to phylloxera resistant rootstocks has led to increased incidence of crown gall at graft unions. Therefore a search for plant material that is resistant to crown gall has been undertaken....
Over the last several years many Oregon winemakers have expressed concerns over the frequency of 'stuck' and sluggish yeast fermentations. These problems are probably due to low nitrogen status of musts at harvest. Malolactic fermentations may also be affected by low levels of fermentable nitrogen in juice and wine. Low...
During the 1994, 1995, and 1996 vintages we designed a series of trials to evaluate the effects of commercial Pinot noir fermentation practices in Oregon on wine composition and quality. Differences have been observed in anthocyanin content, color intensity, polymeric pigment content, phenolic content, and in aroma, flavor, body, and...
A factorial design was used to vary leaf canopy structure of mature Pinot noir grapevines during two consecutive seasons: shoot tipping at full bloom (yes or no), lateral shoot length (no laterals, laterals cut back to 4 leaves at full bloom, laterals allowed to grow undisturbed) and cluster zone leaf...
Three different cover crop treatments were compared for their effects on vine growth, leaf gas exchange, yield parameters and fruit composition. The treatments were: resident plants, an insectary plant mixture and a grass cover. At veraison (August 2 1), photosynthesis rate was lowest for the vines with the grass cover...
Oregon is a leader in production of premium wines in the United States and the industry has been expanding rapidly over the past few years. However, continued production and expansion of vineyards are threatened by infestation of phylloxera, Daktulospaira vitifoliae, an insect that feeds on roots. Most grapevines in Oregon...
For over 14 years there has been a Area Horticultural Extension Agent available to assist winegrape growers in Jackson and Josephine Counties with production problems by conducting educational programs and applied research projects. While the salary for this position is paid by Oregon State University Extension, support funds which pay...
To develop a computer-based information system for grapes and small fruits that will facilitate and increase access to information, and encourage increased communications among everyone involved in the industry.
Objectives 1. Survey Oregon vineyards for the presence, identity and abundance of plant-parasitic nematodes. 2. Relate the distribution and abundance of potentially pathogenic species to viticultural practices and site characteristics. 3. Evaluate the efficacy of Nemacur for reducing populations of plant-parasitic nematodes. 4. Document seasonal changes in the abundance of...
Five replicated rootstock trials established in Oregon's three main viticultural. regions were evaluated for the effect of rootstock on Pinot noir performance. All the trials except Alpine included the following seven rootstocks: ungrafted Pinot noir, 3309 Couderc, 101-14 Millardet et De Grasset, 44-53 Mal6gue, 420 A Millardet et De Grasset,...
During the 1995 harvest season Pinot noir development during ripening was monitored at Woodhall Vineyards (WHV) in Alpine and at three commercial vineyard sites at Croft (CR) Vineyards in Monmouth, Rex Hill Kings Ridge Vineyard (RHKR) in Newberg, and Erath Vineyards (ER) in Dundee. Cluster samples (25) were taken weekly...
Enology Extension at OSU with support from the Oregon Wine Advisory Board provides technical assistance to winery personnel including wine analysis, consultation on production problems, and training through workshops and winery site visits. The Oregon wine industry has grown rapidly in recent years to over 100 wineries. There is a...
The effect of shoot tipping, lateral shoot length and cluster zone leaf removal on yield, yield components, fruit composition and soundness were evaluated on mature Pinot noir grapevines. Shoot tip removal at bloom improved percent fruit set, number of berries per cluster and cluster weight. Elimination of lateral shoots also...
Winemakers commonly attribute differences in color, color stability, and phenolic composition to different fermentation practices. The extraction of anthocyanin pigments and other phenolic compounds from the skins, pulp, seeds, and stems to a large degree determines the composition and quality of red wines.
During the 1994 vintage we designed a...
Grafted grapevines will become increasingly important in Oregon vineyards in order to prevent loss of plants to phylloxera infestations. Several rootstocks are now being evaluated in Oregon for horticultural traits and characteristics related to wine quality. Resistance or tolerance to other plant diseases affecting grapevines needs to be examined as...
Inflorescence Necrosis (IN) has been an unpredictable problem for grape growers in Oregon. The
industry has seen significant losses due to this fruit set disorder in several out of the eight years since its
first description in 1988, particularly in Pinot noir. Little is known of how to prevent the...
Three different green cover treatments were compared in their effect on leaf gas-exchange, vine growth, yield and fruit composition. The treatments were: grass cover, resident plants, and an insectary plant mixture. Photosynthesis, transpiration, and water use efficiency were lower for vines with a grass cover. Leaf area and shoot growth...
Pinot noir and Chardonnay are the two main varieties in Oregon. Together they comprise 60% of the Oregon winegrape acreage, and 61% of the total production for a value of $8,906 (66%). Clonal selection of Pinot noir and Chardonnay have made available a wide range of productivity and quality levels....
One of the goals of the Integrated Production approach is an overall reduction of pesticide use, including the application of fungicides for disease control. Powdery mildew is the most frequently sprayed disease in Oregon vineyards. Losses to powdery mildew vary from year to year, but may be substantial. Because little...
Wines, specifically those in which lactic acid bacteria can grow can cause transient toxic effects due to the formation of biogenic amines such as histamine and tyramine. Some people specifically avoid red wines because they are more often associated with headaches and other discomforts. An understanding of the origin, occurrence...
In 1994-95, the Oregon Wine Advisory Board supported a cooperative study entitled "Crown gall and phylloxera in Oregon grape vines: Biology and treatment of planting stock with hot water dips" with Bernadine Strik and Marilyn Canfield (Larry Moore) as co-principal investigators. We will report our findings on hot water dips...
The 18 winegrape varieties in this trial were in sixth leaf in 1995. Vines were pruned in February to either a Scott Henry (3-4 permanent arms on a vertical trellis using two fruiting wires 12 inches apart at 30 and 42 inch height) plus 2 extra disposal canes on some...
Pinot noir is Oregon's most important wine grape variety, representing 38% of the state's total wine production. Oregon State University began importing Pinot noir clones from California and France in the 1970's to insure that Oregon growers had access to the full range of clonal types. Almost all of the...
The Chardonnay clonal trial was harvested on September 29th this year at the end of a week of unusually hot and dry weather. Most of the vines had been pruned to 20 nodes per vine but crop load was light due to small clusters. Yields ranged from less than 0.5...
The new varietal trial at the Southern Oregon Experiment Station was monitored during the growing season and during ripening by David Sugar and Porter Lombard. Most of the varieties in the trial ripened well this vintage compared to 1993 where not all of the varieties developed adequate maturity. Unusually warm...
Objectives 1. Survey Oregon vineyards for the presence, identity and abundance of plant-parasitic nematodes. 2. Relate the distribution and abundance of potentially pathogenic species to viticultural practices and site characteristics. 3. Evaluate the efficacy of Nemacur for reducing populations of plant-parasitic nematodes. 4. Document seasonal changes in the abundance of...
For over 14 years there has been an Area Horticulture Extension Agent available to assist winegrape growers in Jackson and Josephine Counties with production problems by conducting educational programs and applied research projects. While the salary for this position is paid by Oregon State University Extension, support funds which pay...
During the 1994 growing season, 1,998 dormant wine and table grape cuttings and 2,552 mist propagated plants were distributed to 33 growers from the OSU Mother Block. Sixteen new clones were added to the Mother Block in early spring. This included rootstock, wine and table grape cultivars. The trellising system...
For several years thrips have been suspected of causing shoot damage in the form of reduced leaf size and stunted vine growth in a vineyard in the Cave Junction area of Southern Oregon. While the symptoms described above can be caused by several problems, it was decided in 1992 to...
The Oregon wine industry has grown rapidly in recent years to over 100 wineries. There is a strong need for enology Extension, technical assistance, and technology transfer of relevant research for commercial application. Enology Extension at OSU provides technical assistance to winery personnel including wine analysis, consultation on prodution problems,...
Minimal pruning is a vine management system developed in Australia and now widely used for wine grape production around the world. Porter Lombard started a minimal pruning trial in Cabernet Sauvignon following his visit to Australia in 1988. A replicated trial in Chardonnay was established at Woodhall vineyard in the...
We have studied commercial fermentation practices for three vintages in order to learn how they affect
extraction and stability of anthocyanin pigments and other phenolic compounds in Pinot noir. Wines
were monitored during fermentation, processing, and aging for anthocyanin and phenolic content, color
intensity, and for phenolic profiles using high...
Thirty five vineyard blocks of Pinot noir were sampled at harvest by taking a two hundred cluster sample in 1993. Commercial wines from these blocks were analyzed by HPLC at two and nine months of age. Cluster weights ranged from 72 to 148 g, berry weights from 0.55 to 0.90...
The objectives of this study are to isolate and characterize pathogenic agrobacteria that cause crown gall in grapevines and test hot water dips as a method for eradicating the infectious bacteria . Crown gall is commonly found among Oregon vineyards and the causative agent, Agrobacterium vitis, is known to be...
Wines, specifically those in which lactic acid bacteria can grow can cause transient toxic effects due to the formation of biogenic amines such as histamine and tyramine. Some people specifically avoid red wines because they are more often associated with headaches and other discomforts. An understanding of the origin, occurrence...
Variability in fruit set and yield is a serious problem in Oregon viticulture, particularly with Pinot noir. Climatic variation during the flowering period contributes significantly to this problem by affecting fruit set and cluster weight. Cool wet weather during bloom results in poor set, small clusters, and low yields. Seasons...
Poor set and low yields in 1988 and 1990 were, in part, attributed to Inflorescence Necrosis (IN), a disorder that results in death of flowers and rachis tissue near bloom-time. In isolated areas, IN has caused significant loss of crop in each year since then. Past research at OSU has...
The 18 winegrape varieties in this trial were in fifth leaf in 1994. Vines were pruned in February to either a Scott Henry (4 arms on a vertical trellis using two fruiting wires 12 inches apart at 30 and 42 inch height) or a guyot (a double arm on a...
During the last two years thrips have been suspected of causing shoot damage in the form of reduced leaf size and stunted vine growth in one vineyard in the Cave Junction area of Southern Oregon. While there can be several problems that can cause this symptom in grapes, it was...
We harvested the first significant crop from the Woodhall clonal trials in 1993. Early results from clonal trials can be misleading but there are differences between clones that are already quite apparent in some cases. Many of the clone types could be readily identified this season by plant growth habit...
Four year old vines of 18 varieties were cane pruned, trained to a Scott Henry, thinned before veraison, and harvested in October and November 1993. Two of the varieties, Chardonnay and Cabernet Sauvignon, were used as standards. Only four varieties were spur pruned to reduce cropping or cluster size: Dolcetto,...
Objectives: 1. Survey Oregon vineyards for the presence, identity and abundance of plant parasitic nematodes. 2. Document seasonal changes in abundance of species of important plant parasites in order to identify optimum times for sampling. 3. Evaluate the efficacy of Nemacur for reducing populations of plant parasitic nematodes.
For over 13 years there has been an Area Horticultural Extension Agent available to assist winegrape growers in Jackson and Josephine Counties with production problems by conducting educational programs and applied research projects. While the salary for this position is paid by Oregon State University Extension, support funds which pay...
The Oregon wine industry has gown in recent years to over 100 wineries. There is a strong need for enology Extension, technical assistance, and technology transfer of relevant research for commercial application. Enology Extension at OSU provides technical assistance to winery personnel including wine analysis, consultation on production problem, training...
Since phylloxera's discovery in a commercial vineyard in August of 1990, nine infestations have been verified in Oregon. With over 95% of Oregon's vineyards planted with ownrooted, Vitis vinifera, non-resistant vines, understanding the insect's biology under our conditions has become important for determining management strategies that minimize rate of spread....
Nisin, bacteriocin produced by Lactococcus lactis, Nisin may have the potential to replace (or reduce) sulfiting agents traditionally added to wines to prevent the growth of spoilage lactic acid bacteria. This may be valuable since sulfites are believed to cause toxic responses in sensitive individuals. As a result, the U.S....
The new varietal trial at SOES was monitored during the growing season and during ripening by David Sugar and Porter Lombard (see Winegrape Variety Trial in Southern Oregon). The 1993 vintage was a late ripening season and not all the varieties developed sufficient maturity for experimental wine production. Tempranillo, Viognier,...
Riesling, Chardonnay, and Pinot noir wines from the 1992 vintage were fermented with several different commercial yeast strains. Differences were observed in fermentation rates, wine composition, and aroma and flavor. Preliminary results were reported on in the OSU Wine Grape Research Progress Reports, 1992-1993, Special Report 929, June 1993, OSU...
In experiments in grape skin light transmission in 1991, we found that quercetin (a phenolic compound found in many plants) accumulates in sun exposed grape skin. The accumulation of quercetin in grape skins appeared to be a protective response to solar radiation and we were able to show that quercetin...
Minimal pruning continues to look like a production system worthy of consideration in small scale commercial trials. In 1993, in a trial on Chardonnay at Woodhall vineyard, minimal pruning was compared to standard cane pruned vines on a vertical trellis. This was the second year of the trial.
Oregon Pinot noir wines differ greatly in their color and phenolic profiles and this variability is due to both vineyard and to fermentation management practices. We have observed that Pinot noir fruit composition can vary significantly with vintage, with degree of maturity, with yields, with trellis systems, and with the...
The connection between the fruit-set disorder Inflorescence Necrosis (IN) and high ammonium (NI14+) in affected tissues has led to an investigation of NH4+ assimilation enzymes (principally glutamine synthetase (GS) and glutamate synthase) in grape tissues. Previous work in this department has suggested that toxic levels of NH4+ build up in...
The easiest way to introduce phylloxera to a site is by infested plant material. If a grower can effectively remove any existing phylloxera on new plants, the rate of spread of phylloxera. in Oregon vineyards will be significantly decreased.
The objectives of this study are to determine methods for dipping...
Our objective is to develop methodologies to allow winemakers to precisely control the malotactic fermentation and to prevent spoilage of wines by undesirable bacteria.
There have been significant changes in personnel assignments in the OSU Viticulture program during the past year, resulting in shifts in assignments and responsibilities affecting both research and extension in viticulture. Some of these changes are temporary and the current Extension program in viticulture should be considered an interim program....