Glenn County, Calif., walnut growers are continuing to see a good crop developing, even after a brief of June hot spell.
For several days, the thermometer soared above 100 degrees, sending evapotranspiration rates and water demand ‘way up. But fortunately, that was soon followed by much cooler weather, says Bill Krueger, recently retired University of California Cooperative Extension farm advisor for the county.
“The trees have been looking pretty good,” he said as he closed a 32-year career at the end of June. “The Chandler crop seems to be off a bit compared to last year, when they had a really good season. The older varieties, like Ashley, Vina and Chico, are looking pretty good, and so is Serr.”
He’s received reports of walnut blight occurring on the earlier-leafing varieties. In addition to rains this year when trees were leafing out, the incidence of the disease may also reflect a buildup of bacteria from the wet spring weather of the last few years.
“We’ve seen some pretty good trap catches of codling moth, so it looks like there’s a fair amount of pressure from that pest this year,” Krueger says. He’s expecting the second generation of the insect to start showing up soon.
Normally, growers don’t begin seeing the husk fly until around the middle of July, but by the last week of June he had already heard of some growers who already caught the pest.
Meanwhile, growers continue adding to walnut acreage in Glenn County and surrounding areas. “There’s a tremendous expansion going on in the Sacramento Valley,” Krueger says.
It includes traditional walnut growing areas with deep, well-drained soils near the Sacramento River, where the new plantings are replacing almond and prune orchards, as well as well areas farther west.
“A lot of the new walnut orchards are being planted on ground where trees haven’t been grown before,” Krueger says. “In some cases, they’re even planting walnuts in former rice fields.”
Counting all the new plantings, he estimates that the Sacramento Valley now accounts for at least half of California’s total walnut acreage. Among the area’s drawing cards are lower land costs and more available water than in the San Joaquin Valley, he says.