Temperatures zoomed to more than 110 degrees July 18-19 in California’s San Joaquin Valley, and forecasters are predicting temperatures above 100 degrees to continue into the week of July 27. The fruit is holding up well, however, grower-shippers said.


The valley’s valencia orange harvest is at its peak, and the heat wave is not going to help the crop, said Bob Blakely, director of grower services for California Citrus Mutual, Exeter.


"We expect to see some sunburning, but the problems are primarily going to be cosmetic," he said.


Another by-product of the hot weather, Blakely said, is a tendency to retard sizing, a problem that is rectified when more normal temperatures return.


The heat is causing only minor problems for stone fruit, said Dale Janzen, director of industry relations for the Reedley-based California Tree Fruit Agreement.


Temperatures prior to the heat wave were peaking in the high 90s, which helped condition the fruit to endure the hotter weather, he said.


"The fruit’s been tempered with enough heat because the temperatures have been building over the last several weeks," he said. "And we are cooling to about 70 degrees overnight."


The hot weather could sunburn some fruit not protected by leaves, but that happens every year, Janzen said.


It is a similar scenario for table grapes.


"California farmers have been growing grapes in the valley for generations," said Jim Howard, vice president of the California Table Grape Commission, Fresno. "The grapes know how to handle the hot temperatures, and the growers know how to handle them as well."


While the summer and early fall crops will apparently suffer only minor problems, there could be challenges for navels. The hot weather will not diminish quality, but it could affect the sizing of navels, Blakely said.


"The effect on the growth rate will be the biggest issue, but we won’t know how significant it will be until it is closer to harvest time," he said.