Source: Cecilia Parsons; Ag Alert

Color, sugar content and berry size of many early table grape varieties hit harvest targets last week in the southern San Joaquin Valley.

Harvest in the Arvin area of Kern County is a week to 10 days earlier than normal this year, according to grape grower Ryan Zaninovich. Harvest of the San Joaquin Valley’s 70 to 80 varieties of red, green and black table grapes will continue through November.

Zaninovich, chairman of the California Grape and Tree Fruit League and manager at Vincent B. Zaninovich & Sons Inc. in Richgrove, said warm spring weather is driving earlier harvests in all grape-growing regions of the state. The desert region table grape harvest began in late April and will wind down this month, as harvest transitions to the southern San Joaquin Valley.

Coming off a record-production year of 117.4 million 19-pound boxes for all growing regions in 2014, Zaninovich said yields from this crop are estimated to be about average to larger with excellent quality. An updated crop estimate will be released in July, prior to the peak of the California harvest. Coachella contributes about 5 million boxes to the total.

Zaninovich and retired Kern County Cooperative Extension viticulture advisor Don Luvisi said no serious pest or disease issues are looming for growers. Grape quality is expected to be excellent again this year, with only minimal sunburn where canopies are light.

“When we have good spring weather, that generally means the quality will be high,” Zaninovich said. Grape mealybug is always an issue, but growers have been able to keep them under control, he added. Growers keep up with pest control and suppress powdery mildew early, Luvisi said.

The biggest challenges this season for growers will be water and labor. Most depend entirely on groundwater supplies for irrigation. Adequate water not only ensures higher yields, but also protects vines from stress that invites pests and disease.

“We’re all relying on groundwater and hoping the wells don’t go dry. I’ve heard of a few growers who are having issues with their wells,” Zaninovich said. “We all have strategies for best water use and to protect the longevity of the vines.”

Zaninovich said different varieties of table grapes use different amounts of water during the year. Varieties that are harvested early in the season or have lighter yields use less water than heavier producers or varieties harvested later in the season.

Labor will cost more this harvest season and availability could become a problem for growers later in the season, and many varieties and other hand-harvested crops demand labor, said Barry Bedwell, president of the California Grape and Tree Fruit League.

“There are no reports of shortages now, but the crunch time comes in August and September, when we’re competing with other harvests,” he said.

Harvest crews are paid by the hour with bonuses per box. Bedwell said they average higher than minimum wage, but growers base their pay on the state minimum wage. The harvest requires skilled labor, and crew members can average $10 to $14 an hour, he said. Table grapes are field packed into boxes and trucked to cold storage prior to shipping.

California’s approximately 500 table grape growers are looking at strong prices and robust export sales this year, according to Bedwell. The trend for both is upward, as growers are coming off two strong sales years.

Kathleen Nave, president of the California Table Grape Commission, said table grape growers have been extending their harvest season with new early and later varieties of grapes. Red grapes dominate the top five. Flame, Scarlet Royal and Red Globe are the top three varieties in acres planted. Autumn King and Sugarone are two of the most popular green grapes, while Autumn Royal is the most popular black grape.

“With a longer harvest season and promotion efforts, we expect exports to be up,” Nave said.

Canada, Mexico and China are top export destinations for California table grapes. Bedwell pointed out that while California products are popular in China, that country’s table grape production far outpaces California. With annual production hitting 1 billion boxes, their Red Globe varieties alone equal all of California’s production.

China has begun the process of exporting grapes to the United States, Bedwell noted, and is currently in the pest review process—which could take another three years.

Luvisi said the biggest change in table grape production over the past 20 years has been the development of many seedless varieties.

“Seeded grapes are really hard to find now,” Luvisi said. Older varieties like Thompson Seedless are also being replaced with varieties that hit certain market windows. He noted Kern County table grape growers have planted a newer green variety, Superior Seedless, after taking out Thompson Seedless vineyards. Zaninovich said he has planted another newer green variety, Autumn King, which is a heavy producer.

In the past few weeks, Luvisi said, Kern County growers were checking vineyards for color, sugar and berry size to determine when to harvest. Market demand and prices also drive the decision, he said.

Recent weather has been an advantage. Temperatures above 95 degrees slow down development; cooler days with 85 to 95 degrees push maturity. When bunches of red grapes are 95 percent colored, Luvisi said harvest will begin. Green grape maturity is determined by sugar content. Berries will continue to size until picked, he added.

“We’ve had perfect weather for making sugar,” he said.