Kearney Agricultural Research and Extension Center
University of California
Kearney Agricultural Research and Extension Center

Vine Crops

955 - Control of Grape Insect Pests

Principle Investigator: Kent Daane

Affiliation: UC Berkeley

Contact:kdaane@ucanr.edu

Table, raisin and wine grapes constitute one of the most important and widespread commodity blocks in California agriculture.  Control of insect, mite and spider pests pose a considerable cost to vineyard growers.  We propose to study leafhopper, mealybug and black widow pests in vineyards.  In the three year period (2011-2013) our main objectives are to (1) investigate insect vector relationships with plant pathogen (e.g., grape leafroll associated viruses), (2) improve sustainable control for mealybugs (e.g., mating disruption and biological controls), and (3) investigate chemical controls of black widow spiders.

0306 - Raisin Research

Principle Investigator: Matthew Fidelibus

Affiliation: UC Davis

Contact: mwfidelibus@ucanr.edu

Dry-on-vine raisin growers, particularly those with overhead arbor trellis systems, are striving to reduce labor costs associated with pruning while maximizing vine productivity. They are also interested in reducing the proportion of fruit borne on shoots from basal nodes, the position of which presents management problems. Therefore, we conducted several studies to develop cane length, bud fruitfulness, and productivity data to help guide pruning decisions for the important dry-on-vine (DOV) raisin grape cultivars, ‘DOVine’, ‘Fiesta’, and ‘Selma Pete’, and the traditional raisin cultivar ‘Thompson Seedless’. Internode length varied among cultivars such that ‘DOVine’ and ‘Thompson Seedless’, which had the shortest internode lengths, bore approximately 4.25 nodes per foot of cane, whereas Fiesta and Selma Pete, which had longer internodes, bore 3.9 to 3.5 nodes per foot of cane, respectively. Shoot emergence increased sharply with each of the first five to ten nodes, and approached 100% emergence in the most apical nodes. Emergence was slightly greater and less variable on 15-node canes than 20-node canes, regardless of variety. The number of clusters per node generally increased from nearly zero clusters, at the most basal node, to a peak of between 1 and 1.5 clusters at nodes eight through twelve, before leveling off, or declining slightly, toward the end of the 20-node canes. However, for Fiesta, which generally produced more clusters per node than the other varieties, the number of clusters per node continued to increase throughout the length of the cane. Average cluster weight generally increased with each of the first five or six nodes, and then remained about the same until node fifteen, after which average cluster weights increased again, except for DOVine which had relatively large clusters at the first few nodes. Berry weights were not affected by node position, so variations in cluster weights were mostly due to differences in the number of berries per cluster. Soluble solids were inversely correlated with node position, but the mass of soluble solids (cluster fresh weight x soluble solids) from each node generally increased towards the apex of the cane because cluster weights increased at a faster rate than soluble solids decreased. These data are providing useful information that will lead to pruning guidelines that balance labor and productivity.

102A - Wine Grape Cultural Practices

Principle Investigator: Matthew Fidelibus

Affiliation: UC Davis

Contact: mwfidelibus@ucanr.edu

Yield and fruit quality of two newly released red wine varieties and one standard variety will be compared when grown on two contrasting training and trellising systems.  The vines and trellising systems are already in place, and poised to produce their first crop.  Results from the trial will help determine the true potential of these new varieties while also providing useful information on two relatively new training and trellising systems that could be more widely adopted in the San Joaquin Valley.  It is anticipated that the vineyard will serve as both a research and extension resource.

0405A - New Winegrape Varieties for the San Joaquin Valley

Principle Investigator: Matthew Fidelibus

Affiliation: UC Davis

Contact: mwfidelibus@ucanr.edu

A wine grape variety trial, consisting of 55 16-vine plots, each planted to a different red or white wine grape variety selected from warm-climate Mediterranean regions, was established at the Kearney Research and Extension Center.  Most of the varieties tested were recently released to the industry from Foundation Plant Services so, in many cases, certified selections of these varieties have never been evaluated in California.  All vines were spur pruned, leaving 8 or 9 two-bud spurs per meter of cordon.  We attempted to harvest all white varieties at 22 Brix, and reds at 24 Brix, though inclement weather forced the harvest of a few slow ripening varieties in early November, before they were completely ripe.  At harvest, yield components, rot incidence, and basic chemistry were determined and, for 25 of the 55 varieties, wine lots were made at Constellation Brand’s experimental winery.  The varieties were harvested across a wide range of dates starting with a white cultivar, ‘Fiano’, on 18 August, and ending with 15 red and white varieties which were harvested in the first week of November.  Yields ranged from a meager 2.32 kg per vine from the red cultivar Carmenere, to more than 35 kg of fruit per vine from the white cultivar ‘Trebbiano Toscano’.  Harvest date was poorly correlated with yield, but there was a relatively strong positive correlation between rot incidence and harvest date.  Yield of red and white varieties was more strongly correlated with cluster weight than with the number of clusters per vine, and cluster weight was more strongly correlated with the number of berries per cluster than with berry weight.  Red and white varieties varied widely with respect to pH and titratable acidity.  Other fruit composition data were collected by Constellation and will be shared in a future report.  Wines from the trial will be made available for tasting and analysis in 2012.

0504 - Evaluation of Grape Rootstock Selections

Principle Investigator: Matthew Fidelibus

Affiliation: UC Davis

Contact: mwfidelibus@ucanr.edu

This research project compares 22 nematode resistant selections from the USDA grape rootstock breeding program to the rootstock Freedom, the prevalent nematode resistant rootstock in use in the San Joaquin Valley.  The selections are grafted to Syrah, a black wine grape.  This project will determine if the selections are superior to Freedom in the quality and yield of the fruit produced on their scions.  Data to be collected will be pruning weight, trunk caliper, cluster counts and weight, and berry weight and composition.  Superior selections will be released as new grape rootstocks.

0604 - Rootstock Mothervine Evaluations

Principle Investigator: Matthew Fidelibus

Affiliation: UC Davis

Contact: mwfidelibus@ucanr.edu

In this research project 738 nematode resistant selections from the USDA grape rootstock breeding program are grown in the vineyard.  These selections have been screened for nematode resistance and are being evaluated for propagation ability and to confirm nematode resistance.  Growing the vines in the Kearney Research and Extension Center vineyard will provide cuttings for propagation ability testing and for the production of grafted vines for rootstock trials.  The vines in this project will be grown as own-rooted vines and not grafted.  They are head trained and spur pruned.  Once vineyard testing of the selections is completed (in separate vineyards) superior selections will be released as new grape rootstock varieties.

663 - Pesticide & Nitrate Distribution in Vadose Zone

Principle Investigator: Thomas Harter

Affiliation: UC Davis

Contact: ThHarter@ucdavis.edu

The unsaturated zone is the link between the crop management zone and groundwater. In the San Joquin Valley it includes the root zone (upper six feet) and the deep unsaturated zone, which can be several tens of feet thick. The unsaturated zone acts as a critical buffer to protect groundwater from nonpoint and point sources of pollution. Percolation of water through the unsaturated zone is a major component of recharge to local groundwater systems in all of California’s agricultural basins. Under various state and federal regulatory guidelines, agriculture is increasingly assessed for its quantitative contribution to nonpoint source pollution of groundwater. Currently, the effects of agricultural management practices on groundwater quality are evaluated by assessing the bulk nitrogen (and pesticide) leaching from the root zone but little is known about the role of the deep unsaturated zone in mitigating and transferring contaminants to groundwater. The overall goal of this project is to improve our understanding of the role of the unsaturated zone as the link between agricultural management practices and groundwater quality. The field site is providing a realistic laboratory to study in particular the transport of nutrients to groundwater. Over the past six years, we have developed and published a detailed characterization of the vadose zone at this field site, which is now the most detailed characterized vadose zone research field site in California. Our objective is to maintain this field site as a live laboratory for related follow-up research. We are open to working with any cooperator interested in putting the field site under production.

1103 - Grapevine Water Use

Principle Investigator: Larry Williams

Affiliation: UC Davis

Contact: lewilliams@ucanr.edu

Grape growers need to become more water use efficient as fresh water may become limited in the future due to limited due to inadequate rainfall in California.  The proposed research will provide wine grape growers in the San Joaquin Valley objective metrics on the water use efficiency (yield per unit of water used) of numerous wine grape cultivars grown in a common vineyard at the Kearney Agricultural Research and Extension Center.  This project will also examine the effect of several irrigation techniques on water use efficiency of those cultivars and effects those irrigation treatments may have on grape and wine quality.

Webmaster Email: kcbyrum@ucanr.edu