Positive Signs for California Grape Harvests

The 2016 Mendocino County wine grape harvest got underway the first week of August as growers began picking Chardonnay and Pinot Noir for sparkling wines. The harvest for still wine production is expected to start by the last full week of the month, according to Zac Robinson.

Robinson is a co-owner of his family’s Husch Vineyards. They grow 30 acres of Chardonnay, Pinot Noir and Gewürtztraminer in the Anderson Valley and make wines from grapes grown here and elsewhere in the county.

While beginning some two weeks later than the record-early start in 2015, this year’s harvest is, nonetheless, coming on several days earlier than usual, Robinson notes. He attributes that to a uniformly warm growing season.

“The vineyards look wonderful,” says Robinson, who, as a wine maker, admits to being an eternal optimist. “This season has been going well. The canopies are healthy. Insect and disease pressures have been low this season, and the fruit looks really pretty.”

Rains that fell frequently but in relatively small amounts throughout the winter and early spring filled area ponds. That hasn’t happened since 2012. “The past three years were hard droughts,” Robinson says. “Rainfall this year has been average. But, given the previous dry seasons, it’s seemed like a plethora of water.”

The red grapes he crushes hadn’t yet reached full size by the second week of August. Weights of clusters he sampled then indicated yields are likely to come in no higher than average at best. Meanwhile, production of his white varieties appears be average or better

Although always on the watch for any flare up of powdery mildew, usually this fungal isn’t a major threat to his vineyard, Robinson notes. And, that was the case this year.

His main insect pest, leafhopper, hasn’t been much of a concern to him this year, either.

His IPM program, which dovetails with his efforts to control the quality of his grapes, focuses on pre-emptive action to limit any buildup in leafhopper numbers.

“We try to stay ahead of leafhoppers all season long by removing the food source for the first and second generation,” he says. “We do that by removing the first and second leaves on each shoot to expose the fruit to some sun. These are the same leaves where the first several generations of leafhoppers live.

“If we get the timing right, the nymphs are on the leaves that we drop on the ground where predators feed on the nymphs. Knocking the populations back like that up front can lead to a big benefit in controlling leafhoppers late in the season.”

If prolonged, such high temperatures and sun burn could challenge wine makers by dehydrating the grapes and pushing sugar readings above desired levels and by breaking down the skins and altering tannin content. It would also force growers to pick up the pace.

“Instead of a leisurely harvest where the ripening and harvest work fits a certain schedule, suddenly everything would be ready to be picked tomorrow,” Robinson says. “Then you have to race and make logistical compromises to salvage the crop rather than concentrating on picking the grapes at peak quality.”

Early Central Coast results

The first week of August marked the start of this year’s Central Coast wine grape harvest. That’s a little earlier than usual. But it’s not as early as some had been expecting several months ago. That was after vine and berry growth had shot off a fast start, but before some hot weather in June and again in July slowed things down in the vineyards, notes veteran grower John Crossland.

The harvest kicked-off in such areas as the Edna Valley, in the southern part of San Luis County, with growers picking Pinot Noir and farther north in Monterey County as crews began bringing in the first of the Chardonnay, Pinot Gris and Pinot Noir crops, Growers in the Paso Robles area of San Luis Obispo County followed in mid-August as they began harvesting their earliest white grapes, mainly Sauvignon Blanc.

“So far, it hasn’t been a large crop. That’s for sure,” says Crossland, who’s been growing grapes for more than three decades.

His company, Vineyard Professional Services, Inc., manages more than 3,000 acres of grapes in the Paso Robles-Templeton area and consults with other Central Coast growers and vintners.

Growers here, who rely entirely on ground water to irrigate their vineyards, have had to struggle through another rain-short year.

“We’re still in a drought,” Crossland says. “What rain we got this past winter wasn’t nearly as significant as growers in the North Coast received.”

For example, annual rainfall in the area east of Paso Robles averages from 10 to 12 inches. From July 1 of last year to June 30th of this year rainfall totaled about 8 inches, Crossland notes.

Meanwhile, as water tables continue to drop, irrigation water is becoming saltier forcing growers to deal with higher salinity levels in their soils.

“Compared to last year’s very small crop, the clusters this year are filled out better with more shouldering and more berries per cluster.”

What’s more, after sitting on the sidelines waiting to get a better idea of the size of this year’s crop, buyers are back on the phones, securing supplies for their wineries and bidding up grape prices, he adds.

Vineyards haven’t been under any unusual pressure from such pests as leafhoppers and spider mites this year, Crossland notes. However, despite this season’s heat spells, growers saw more outbreaks of powdery mildew than usual.

A long-time advocate of sustainable farming practices, Crossland is a member of the non-profit Vineyard Team, a grower group dedicated to sustainable winegrowing, and helped write the Code of Sustainable Winegrowing Practices developed by the Wine Institute and the California Association of Winegrape Growers (CAWG) to promote environmental stewardship and social responsibility in the California wine industry.

Interest by growers in farming in a more economically and environmentally sustainable way has continued to increase over the past few years, Crossland says. This includes more participation in the Vineyard Team’s Sustainability in Practice (SIP) Certification Program and the Certified California Sustainable Winegrowing (CCSW-Certified) offered by the California Sustainable Winegrowing Alliance.

These growers are also focusing more attention on their human resources, a key component of sustainable farming, he adds. “With the declining number of farm workers, growers are realizing the value of developing the type of relationships needed to keep these workers,” he says. “So they’re showing their workers greater respect and providing them the training they need to work safely and the conditions, including such basics as plenty of water, shade and adjusting schedules to avoid working in extremely hot temperatures, needed to protect their health.”

Fresno County grape crop

It’s too early to say for sure, but the quality of this year’s raisin-type grape crop in Fresno County, the heart of California’s raisin production, appears to be much improved over last year.

The sugar content of a berry is associated with bigger berries and higher soluble solids (º Brix), which result in a better-quality raisin. This season, both measures are higher, reports George Zhuang, University of California Cooperative Extension viticulture advisor for Fresno County.

“Growers are telling me the sugar accumulation by Thompson seedless and other raisin grapes looks really good,” he says. “Of course, that can vary, depending on the vineyard and cultural practices.”

Last year, many growers were disappointed by the quality of raisins that came out of their vineyards. That may have reflected the stress on the vines from four years of drought and limited supplies of irrigation water, he says.

Then, again, both poor strategies for sampling grapes collected to measure soluble solids just prior to harvest as well as variations in fruit maturity within a vineyard can affect the determination of raisin quality, he adds.

One key to maximizing raisin quality is to maintain a healthy canopy during the growing season.

“This will help the leaves maintain the photosynthetic activity needed to produce the carbohydrates that the vine uses to grow the berries and accumulate sugar,” Zhuang says.

This year’s Fresno County raisin-type and wine grape crops have been ripening at a quick pace, he notes.

Typically, growers begin harvesting Thompson seedless grapes when sugar levels reach about 20º to 21 ºBrix readings.

The Selma Pete variety is popular for DOV (dried-on-the-vine) production, where the canes are cut to allow the grapes to dry for several weeks before the clusters are harvested with machines. This year Fresno growers began cutting canes in late July or early August. That’s similar to last year.

The county’s 2016 wine grape harvest also began a little earlier than in 2015 with such white varieties as French Colombard for high acid programs and Pinot Gris.

Unlike the production of most wine grape varieties in Fresno County, which has remained stable or declined in the past few years, acreage planted to Pinot Gris, is on the rise. From 2014 to 2015, the number of county acres planted to this variety increased by 26 percent.

This is in response to increasing demand from wineries for Pinot Gris grapes, Zhuang notes. However, yields of this variety tend to be low – from eight to 10 tons per acre. That compares to French Colombard production which, typically, ranges from 15 to 20 tons per acre.

To explore possible options for boosting Pinot Gris yields and fruit quality, Zhuang is planning to begin field trials to evaluate productivity and fruit characteristics of 12 different Pinot Gris clones from Foundation Plant Service.

This year Fresno County vineyards were under unusually high pressure from powdery mildew and growers had to adopt a very aggressive spray program. Growers should always monitor and base their management plans on the powdery mildew pressure in their own fields. However, combining the use of various tools, such as the UC-developed Powdery Mildew Risk Index, to determine the need for treatment with proper timing of spray applications can help growers control powdery mildew in their vineyards, Zhuang says.

Meanwhile, the vine mealybug threat to Fresno County vineyards continues to grow. In the past, most growers have been able to control this pest with a single application of Movento between early-May and mid-June.

“This year, the vine mealybug was their biggest insect control challenge,” Zhuang says. “Populations were pretty high. In addition to their Movento treatments, many growers sprayed another insecticide, like Admire or Applaud, in April to keep numbers down.”

Source: Western Farm Press

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