Frutas y HortalizasAgo. 3, 2016
California: Altas temperaturas pueden afectar cosechas de pasas, nueces y tomates
RED BLUFF, Calif. — Afternoon temperatures that have soared to near 110 degrees in the Central Valley have caused headaches for fruit, nut and tomato growers.
Young, vigorous walnut orchards have sustained heat damage to leaves, portending a harvest season in which darker, damaged kernels further sap growers’ income, said Rick Buchner, a University of California Cooperative Extension adviser.
“I think we’re going to have to deal with quality issues this year,” said Buchner, who is based in Red Bluff. “That’s problematic because the prices are generally down and handlers want good quality.
“That’s the big deal and we probably won’t know that until we see the grade sheets … probably around the first week of October,” he said.
Walnut orchards were being treated with sunburn spray last week as well as for codling moth and husk fly, according to the National Agricultural Statistics Service. Walnuts are one of many crops that have shown signs of wilting in the searing sunshine.
Temperature spikes in July also caused instances of blue prune, in which plums for prunes dropped from trees prematurely, Buchner said. Prune production in California is already expected to be less than half of what it was last year because storms in March disrupted the bloom.
“It’s way off weight-wise just because of the poor set,” Buchner said. This year’s crop is expected to weigh in at about 45,000 tons, down from the 107,000 tons that came out of driers in 2015, according to NASS.
The trouble follows a stretch in which parts of the Central Valley closed out July with eight or nine straight days of triple-digit afternoons, spiking at 111 degrees in Redding and 110 in Red Bluff on July 28, according to the National Weather Service.
Elsewhere during that period, temperatures got as high as 107 in Modesto and 109 in Fresno, the weather service reported. With 14 days in triple digits, Fresno averaged a high of 100 degrees for the month.
Among the crops impacted by the high temperatures are tomatoes, which have started to soften, Arbuckle, Calif., grower Darrin Williams said. If such high heat persists in August, growers may see a little more sunburn and diminished quality, he said.
“I don’t think it’s going to have a devastating effect because everyone is on drip these days and it mitigates the impacts of the heat,” said Williams, a California Tomato Growers Association board member. However, the heat could cut yields, he said.
“It’s a problem,” he said. “It’s hard to quantify loss in yield because every variety is handled differently. With my crop, it’s probably going to cost me a ton or two in paid yield (out of a 60-ton crop) … It depends on how much longer the heat wave lasts.”
The heat is hastening the ripening of some summer fruit, including peaches at R and K Orchards in Corning, Calif. Heat in past years has caused peaches to drop or even cook on the tree, but the orchards have made it through this heat wave largely unscathed, co-owner Karen Mills said.
The timing of this heat spell was fortunate in that harvest was already proceeding, she said.
Some strawberries in the Central Valley sustained damage, growers said. But temperatures remained cooler in the prime growing regions on the Central Coast, parts of which are also shrouded by smoke from the more than 62-square-mile Soberanes Fire near Big Sur, California Strawberry Commission spokeswoman Carolyn O’Donnell said in an email.
Among other crops, according to NASS in Sacramento:
• The high temperatures are causing re-greening of Valencia oranges, which prompts growers to treat them and divert them to domestic markets as some trading partners won’t accept chemically treated fruit.
• Pistachio harvests are expected to be early this year with good yields, as new almond and pistachio plantings are leafing out well in response to the warm temperatures and irrigation. Stone fruit and grape harvests are also a couple of weeks ahead of schedule.
• Hot conditions are taking their toll on rangelands, with non-irrigated pasture and range in lower elevations rated from fair to very poor. Foothill forage is in fair condition, according to the agency.
The federal Climate Prediction Center expects temperatures to dip below normal in much of Northern California in early August, but the month as a whole is expected to be hotter than normal throughout the West.
The agency in mid-July issued a watch for La Nina, noting there’s as much as a 60 percent chance that the oceanic phenomenon that favors northern storms develops during the fall and winter.