By the end of May, Steve Kister’s raisin crop was off to the best start in three years.
His 300 acres of raisin grapes near Kerman, Calif., include field-dried Thompson seedless and an increasingly larger share of dried-on-the-vine Fiesta and Selma Pete on flat overhead trellises.
Above average April rains didn’t seem to have hurt his crop, and he reports very little pressure from powdery mildew. In fact, he suspects warmer than normal March and April temperatures helped his vines, and they are on target for producing a good crop in terms of yield, maturity and quality,
“The bunches look good and berries are even and sizing nicely,” says Kister, the third-generation of his family to grow raisin grapes. “The canopy growth of the flat overhead vines is way ahead of the last two years — that’s another indication that this season the crop is starting earlier and is much better.”
During the previous two springs, cool, wet weather resulted in a late, erratic bloom. “Then, we knew we were off to a really light start,” he says. “It seemed to take forever for the vines to finish blooming, but this year the bloom started early and finished quickly.”
Normally, he looks for his vineyard to begin blooming in mid-May. This year, some of his Fiestas and Selma Petes were sporting blooms May 6.
While his Thompson fields are looking good, the developing crop is not as even as the other two varieties, and bunch counts on the Thompsons are down from last year. He attributes that to the variety’s big but somewhat disappointing crop in 2011. Because it matured so late, weight of the individual berries was down.
“With an early spring this year, we should have good maturity and good crop weight when it comes time to cut the canes of our Fiesta and Selma Pete grapes,” he says.
A large leafhopper hatch in the week beginning May 20 prompted Kister to spray an insecticide to control them. He expects one treatment will be enough to contain the leaf-feeding insect, whose numbers tend to vary from one year to the next.
During June he’ll continue to dust vines with sulfur for powdery mildew control and to train canes on the flat overhead trellises. This includes some young Selma Pete vines, which have replaced Thompson seedless.
He controls weeds in the replanted fields and in the Thompson blocks with mowers. His most troublesome weed is nutsedge.
“We call it nutgrass, and we’re seeing a lot of pressure from it,” he says. “This year, it seems to be worse than usual. We think it’s developing resistance to Roundup, so we’re adding other herbicides, like Goal or Shark, when we apply Roundup.”
Concerns about availability of surface water for irrigation this year have eased somewhat. Earlier, Kister was expecting his local irrigation district to deliver water only in April, May and June. But, that was before the welcome late spring rains. “Now, based on what I’m hearing from the district, I think our water season will be extended — that will really help.”
While the supply of irrigation may be improving, he is beginning to question how much labor will be available to harvest the grapes.
“I haven’t heard anyone say there has been an abundance of labor for picking tree fruit this spring,” Kister says. “Also, I’ve already seen local advertisements from apple growers in Washington looking for farm workers this fall.”