Raisin grape growers in the San Joaquin Valley are watching their crops develop at a faster pace than last year, when cool, wet weather for much of the season slowed growth.
As of mid-June, berries were developing nicely, says Steve Spate, grower representative for the Raisin Bargaining Association at Fresno, Calif.
“The warm weather has us on a very good growth path. Although the bunch count is down about 19 percent from last year, it’s still pretty good – around 30 bunches per vine in many fields.”
Growers will soon get an idea of crop quality when berries begin softening and start to take on sugar, likely to occur during the first 10 days of July. But, even good sugar levels when grapes are picked in September is no guarantee of good raisin quality. “We won’t know that until the berries dry down,” Spate says.
The more favorable weather this year has also kept powdery mildew pressure down from the high levels of the past few years.
“Powdery mildew has been pleasantly absent,” Spate says. “Growers have been diligent in treating the disease the past several years, so fields were clean at the beginning of the season.
So far, insect numbers have been down as well, which Spate credits to grower control programs — making timely pesticide applications to keep any problems from getting out of hand. Leafhoppers, which can produce three generations a season, appeared early this year in some locations, he says, and he expects mite numbers to start building as the summer heats up.
Like other San Joaquin farmers, raisin growers are dealing with less surface water for irrigating their crop this year.
“Deliveries didn’t start as early as expected and won’t last as long as needed,” Spate says. “So, many growers will probably have to pump water for their last irrigation.” For those who flood irrigate, that would probably be no later than the first part of August, which would allow time for row middles to dry for harvesting and to improve sugar development before grapes are picked.
More disturbing to growers is the possibility of an inadequate supply of labor to harvest the crop, the result of stepped-up efforts to prevent illegal immigration from Mexico.
“Already there have been indications of a shortage of workers for the tree fruit crop this year,” Spate says. “If that carries over to our raisin grape harvest, it could be a real concern for growers.”