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Lack of rain may sap California wine grapes’ reserve

Lack of rain may sap California wine grapes’ reserve
California vineyards will likely need irrigation much earlier than normal. It’s a good time to assure that water will be delivered to wine grape crops as temperatures warm. Adding too much nitrogen can spur vegetative growth that means even more demands for water.

The lack of rain that has punctuated California’s fall and winter could have sapped some of the reserve for the state’s wine grapes and could lead to uneven bud break and other challenges.

And it’s a good time — well before those grapes start to form — to take a look at how to assure that water will be delivered to the crop as temperatures warm.

That was among advice given to those who attended a grape grower tailgate meeting in the Parlier area presented by the San Joaquin Valley Winegrowers Association and California Sustainable Winegrowing Alliance.

The Running Luck Ranch meeting was one of three sessions at which topics included tractor safety, sustainable growing practices, crop insurance, irrigation management for a dry season and pest and disease management. The other meetings were held in Bakersfield and Ceres.

“I guess we can’t hear too much about water this year,” said Bill Chandler, a Fresno County grower, after the program ended.

Indeed, participants in the tailgate session got their fill — not their fill of water perhaps, but of talk about it.

In his discussion of pest and disease management, consultant Ron Brase warned that the dry fall and winter could mean decreased carbohydrate accumulations in vines, which could be problematic.

“It could mean increased susceptibility to freezing, though that has not been a problem this year,” he said. “And it could mean erratic bud break, reduced spring vigor and an early season boron deficiency.”

Moreover, the erratic growth in vines “could raise havoc with phomopsis,” Braise said. And he suggested use of a boron foliar might be in order.

Brase, president of AgQuest Consulting Inc. in Fresno, said it’s important growers assess the moisture levels in their vineyards with instruments that could include hand probes and augers.

“Vineyards will likely need irrigations much earlier than normal,” he said.

As with several other speakers, Brase recommended growers use Internet searches to find a wealth of information, including assessment of powdery mildew risk.

His pointers included:

• Don’t wait to take preventive steps for phomopsis or leaf spot. “If rain is forecast, treat,” he said, pointing out that rain can spread the fungus.

• Combating powdery mildew, which has been a major problem the past three years, means assessing risk and having a treatment plan. Once it has evolved to a full-blown infection, it may be impossible to clear out of grape clusters.

• Vine mealybug can be controlled with chemicals that include Movento and Admire. Movento has the added quality of suppressing nematodes.

• Some treatments can be lumped together. For example, treatment for omnivorous leaf roller and vine mealybug and application of foliar zinc spray can be done with powdery mildew treatment.

Apply additional water

Deborah Miller, president and owner of Deerpoint Group Inc. in Fresno, echoed Brase’s point that growers should know the moisture levels in their fields and may need to apply additional water to shore up vines that lost some reserve storage of carbohydrates, particularly if they skimped on post-harvest irrigation.

“This is a bad time to be low on water,” she said.

Aside from the soil itself, Miller said, it’s important to look at vine stress and to be aware of just how much water is being applied per acre.

Adding too much nitrogen, she said, can spur vegetative growth that means even more demands for water.

Now is a good time to flush irrigation systems and look at filters. She warned against opening too many lines too quickly while testing them because it can reduce water pressure and prove ineffective: “It can cost several days of labor and result in nothing being accomplished.”

Miller said growers may need to consult with water district officials if they have water quality issues. She cited as an example problems that are developing as districts cut back on costly chemical treatments. Instead, Miller said, they may use a system called “chaining,” in which a chain is used to manually remove aquatic weeds and algae.

In other presentations at the tailgate meeting:

Jack Passarella, safety consultant with The Zenith, a workers compensation insurance company in Fresno, talked of tractor safety.

He said growers should have a manual for every tractor they operate, and one source for those manuals could be the Internet. He also recommended using the Internet to scope out Cal-OSHA requirements.

“They have a very good website, some really good information,” he said.

Passarella said considerable emphasis is being placed on heat illness, and growers should have training programs and outlines for emergency procedures — including how to direct emergency responders to the work site.

A relatively new emphasis this year is on “confined spaces” such as standpipes because of a spate of 13 deaths last year.

Growers should also have a speed limit for their farms, he said. He also emphasized a need for rollover protective structures, seatbelts, shields for moving parts and avoidance of riders on tractors.

Multiple peril crop insurance

Guri Bangu, with Rain & Hail Insurance Services, talked of multiple peril crop insurance.

He said grapes are insurable in the fourth growing season. For grafts, it’s the third season after grafting. The vineyard must have produced 2 tons of grapes per acre in one of the last three crop years in most cases.

Lisa Francioni, program manager for the Sustainable Winegrowing Alliance, said that a third edition of a self-assessment workbook is being developed on sustainable wine grape growing.

The program is seeking input on chapters on human resources and “neighbors and community.”

Francioni also said it is important growers have a handle on “performance metrics,” that they know, for example, how much water and energy they use to produce a crop.

She said it can be expected that there will be great variability in those resources used, due in part to wide variability in types of soils.

Francioni said growers can participate in performance metric workshop webinars from 10 a.m. to 11 a.m. April 26 and May 22. Those webinars are being sponsored by the California Association of Winegrape Growers and the Wine Institute.

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