As his raisin crop moves closer to harvest, Fresno County raisin and currant producer Dennis Wilt likes what he sees.
“The grapes are looking very good,” he says. “I think packers are going to be happy with the quality of the raisins this year.”
He and his wife, Johnell, own D& J Farms at Biola, Calif., with 142 acres of Thompson seedless and 30 acres of Zante currants. Some of the vines were planted by his grandfather 97 years ago.
This year’s crop stands in marked contrast to the 2008. “Last year, we couldn’t get sugar,” Wilt says. “Many growers waited really late to pick grapes and still only got 18 to 20 Brix. Quality was generally poor.”
Had he picked his grapes earlier this month, before they matured, he figures they would still have made better raisins than the mature grapes he harvested last year. This year, by the first week of August, they were averaging around 18 sugar; exposed grapes on the canopy tops tested as high as 22 and 23.
“Since you’ll gain about 1 to 1.5 points a week, the overall crop should be pushing about 22 when we begin harvesting around Labor Day,” Wilt says. “These grapes will make nice raisins.”
It’s a similar story with his currants, which began coloring unusually early, in mid-July. To boost sugar even more, he’ll wait to start picking until the third week of August, by which time he expects sugar levels to be around 23 to 25.
Wilt attributes the high quality of his grapes this year to weather — mild, even temperatures in the spring and a summer characterized by warm days and cool nights. “The vines didn’t stress a lot this year,” he says.
The weather, he figures, also dampened activity of his two main pests, mites and leafhoppers. An unusually heavy rain in late May and cool weather since then evidently disrupted their reproduction.
“Mite damage in this area has been much less than normal, and we’ve had very few leafhoppers,” Wilt says.
As a result, unlike normal years, when he sprays the pests in late June or early July, he had applied no insecticides as of early August and doesn’t expect he will need to do so for the remainder of the season.
Pesticides include sulfur and products derived from natural pyrethroid sources, which he uses on 100 acres of his Thompson seedless that qualified for organic certification this year. This follows a three-year transition from conventional practices using manufactured chemicals.
His main reason for adopting organic practices is a much more attractive price for these raisins. For example, last year when he was selling non-organic Thompson seedless for $1,200 a ton, organic growers were receiving an extra $800 a ton premium, Wilt says.
“I don’t expect that spread to stay as wide, as more growers start producing organic raisins,” he says.
Meanwhile, a portion of the higher price is helping pay for the extra work involved in producing an organic crop. While Wilt can mow weeds within the rows of his vineyards, he uses a propane burner to clean up weeds around the irrigation valves at the row ends. Controlling mildew is more intensive in organic production than with conventional practices. Instead of using synthetic compounds to control mildew, Wilt applies sulfur.
On the other hand, one application of a manufactured chemical at bloom can protect against mildew for up to about three weeks. “With conventional chemicals I can buy three weeks of sleep at night,” Wilt says.
Are his organic grapes worth the additional expense of time and labor? “I’ll find out this fall when I get my check for the raisins” he says.