It’s been a while since California growers have experienced a wet year with a plentiful snowpack and water supply. Weather conditions this season, though, have pushed harvest back for most grape growers and powdery mildew pressure has been unusually high for growers that didn’t stay on their spray programs with just the right timing. Watch this brief interview with UCCE Viticulture Farm Advisor George Zhuang as he explains, and read more about it in American Vineyard Magazine.
In addition to frost damage in the spring, San Joaquin Valley vineyards also experienced severe heat stress as well that took a toll on the crop. Watch this brief interview with UCCE Viticulture Farm Advisor George Zhuang as he shares how growers can better prepare their vineyards for future heat waves — as discussed at the recent Grape, Nut & Tree Fruit Expo in Fresno. Read more about it in American Vineyard Magazine.
Please thank this video’s sponsor Suterra for their industry support.
While innovations in vineyard mechanization have come a long way, labor challenges still prevail in the California raisin industry — and those issues have been amplified since the pandemic. Watch this brief interview with UCCE Viticulture Farm Advisor George Zhuang as he shares what labor-saving options growers have to stay in the game. Read more about it in American Vineyard Magazine.
Please thank this video’s sponsor Suterra for their industry support.
Most agricultural news coverage of the wildfire impact last year focused on the wine grape industry. Though raisins don’t share the same concern for smoke taint as wine grapes, the lack of radiant sunlight due to smoky overcast skies had a significant effect on the sugar accumulation and natural drying process for much of Central Valley raisin crop last year. Watch this brief interview with UCCE Viticulture Advisor George Zhuang as he shares some key insights for growers moving into another dry season, and how to better prepare for harvest should last year’s circumstances reoccur. Read more about it in American Vineyard Magazine.
Please thank this video’s sponsor Vmech for their industry support.
Recently planted Pinot Grigio and wondering how much yield to prepare for in its early years? Watch this brief interview with UCCE Viticulture Advisor George Zhuang as he shares some key insights for growers from a San Joaquin Valley perspective. Read more in American Vineyard Magazine.
Please thank this video’s sponsor Suterra for their industry support.
Thinking of planting a new vineyard? Watch this brief interview with UCCE Viticulture Advisor George Zhuang as he shares some important layout considerations to save money and maximize efficiencies. Read more about it in American Vineyard Magazine.
Please thank this video’s sponsor Suterra for their industry support.
Grape growers last summer experienced some pretty significant periods of hot weather that, for some, negatively impacted the health of their vines and crop yield. In the center of much of this heat, Fresno County UCCE Viticulture Advisor George Zhuang has been researching ways to reduce the impact of such temperatures which are sure to return to both the Central Valley and other parts of the state. Watch this brief interview with George, reporting from the Grape, Nut & Tree Fruit Expo as he explains. Read more about it in American Vineyard Magazine.
Kearney, Calif., (August 21, 2017) – Excitement over the new Sunpreme raisins was evident at UC Kearney Grape Day Aug. 8, 2017. As soon as the tram stopped, dozens of farmers and other industry professionals rushed over to the vineyard to take a close look and sample the fruit. Raisins pulled from the vine were meaty with very little residual seed. The flavor was a deep, sweet floral with a muscat note.
Sunpreme raisins drying on their own in a Kearney vineyard.
Sunpreme raisins, bred by now-retired USDA breeder David Ramming, promise a nearly labor-free raisin production system. Traditionally, raisins are picked and placed on paper trays on the vineyard floor to dry. The development of dried-on-the-vine varieties opened the door to greater mechanization. Workers would cut the stems above clusters of grapes, which then dry out in the canopy and are harvested mechanically. The new wrinkle with Sunpreme is that grapes ripen and then start to dry on their own – no cane cutting needed.
UCCE specialist Matt Fidelibus is conducting rootstock and trellis system experiments on Sunpreme raisins.
“We didn’t know a lot about this variety,” Fidelibus said. “We’ve found it to be very vigorous.”
Fidelibus said the raisins take about a month to dry, and one challenge is the tendency for dried raisins to drop off the vine.
“We want to keep the self drying and stop self dropping,” he said.
Ramming discovered the Sunpreme variety in a Thompson seedless table grape variety trial in the mid-1990s. He was going down the row, saw clusters of raisins and screeched to a stop. He had discovered Sunpreme. The variety is not yet available for commercial production.
Fighting nematodes with new solutions
Also during Grape Day 2017, UC Cooperative Extension nemotology specialist Andreas Westphal outlined research underway to keep nematodes at bay.
“There’s no methyl bromide in commercial planting,” Westphal said. The very effective fumigant was banned because of it’s tendency to deplete ozone in the atmosphere and the risk to human health because of its toxicity. Many farmers have turned to Telone as an alternative, however it is expensive and its use is limited by a township cap.
Westphal is comparing alternative treatments for clearing the soil of the tiny worms that feed on vine roots and inhibit vineyard productivity.
“Some companies are coming up with new chemistry,” Westphal said. “Our challenge in the perennial world is that the roots go so deep.”
Seven new products and Telon were drenched in different replicated research plots. Some areas were left alone to serve as control. Three times the number of Sauvignon Blanc vines were planted in the plots compared to a typical vineyard so researchers could take out plants twice and examine the roots for evidence of pests.
“We are excited to see significant growth differences among the treatments,” Westphal said, pointing out a row that was visibly shorter and less vigorous. “It amazed me. Three years after treatment, and it never grew back out of it.”
Work is still ongoing, but Westphal said he believes some chemical treatment could be available in the future to help reduce nematode pressure.
To deal with nematode populations, Westphal encouraged growers to sample soil and communicate with the diagnostic laboratory to determine what pest nematodes are in their vineyards, and then use that information for root stock selection.
“Growers should not forget the value of nematode-resistant rootstocks,” he said. “Plant material needs to be chosen very carefully when different species of nematodes are present.”
UCCE viticulture advisor emeritus George Levitt, left, chats with retired USDA breeder David Ramming at Grape Day 2017.
At the Annual Grape, Nut & Tree Fruit Expo in Fresno, UC Viticulture Farm Advisor George Zhuang provided some timely advise to growers on how to go about their postharvest vineyard irrigation and fertilization. Watch this brief video & read American Vineyard Magazine for more details.
