With good control of earlier disease and insect threats, little sunburn injury, and a sizeable nut set, this season has all the makings of an excellent crop for San Joaquin County walnut growers. But they’re likely to be delayed in starting the harvest.
Although the crop could still make up some of setback in nut maturity caused by cool weather this year, growers probably won’t begin shaking their earliest varieties until about Sept. 15-20. That’s a good 10 days to two weeks later than usual, says Joe Grant, University of California farm advisor for San Joaquin County.
“Pretty much all of our varieties have set a decent crop this year,” he says. “The exception is Serr. We don’t have a lot of it, but where growers didn’t use the growth regulator ReTain to help correct for pistillate flower abortion, the crop is noticeably on the light side.”
Concerns about an unusually heavy early season nut drop in Vina orchards have vanished now that the trees are bearing a good-size crop, Grant says.
Despite the abnormally wet spring, the amount of walnut blight in orchards has been surprisingly low, he says. Growers have been able to keep codling moth under control despite significant population pressure from this pest earlier in the season. And, unlike areas farther south in the San Joaquin Valley, navel orangeworm is not expected to cause big problems unless harvest is delayed after hull-split begins.
The lack of too many 100-degree or hotter weather in July has also been good for San Joaquin country walnut growers. “We’re not seeing a lot of the sunburn injury that we normally observe,” he says. “So, barring any bad weather between now and harvest, quality of the crop should be excellent.”
Even then, though, weather could still cause major headaches with a delayed harvest. As of the fourth week of August, it appeared that the mid- to late-maturity varieties — which represent the bulk of San Joaquin County’s walnuts — won’t be ready for picking until the last half of October, Grant says. “That’s also when it normally starts raining here, which is the big concern. Rain then would slow the harvest and cause a backup for hullers and hydrators.”