What is in this article?:
- Walnut grower prepares for a hot, dry summer, increasing pest threat
- Moth battle
- This year’s walnut bloom has been strung out. The straggly bloom may be the result of insufficient chilling hours this past winter.
Pushed by warmer than usual temperatures this spring, the crop on Dave Taylor’s San Joaquin County walnut trees were about two weeks ahead of normal in maturity.
His operation, Anderson Barngrover Ranch, near Linden, Calif., includes 320 acres of walnuts.
This year’s bloom has been strung out. For example, by May 14, the nuts on some of his Chandlers had grown to about three-eighths to one-half inch in length. At the same time, other Chandlers had just finished flowering. Taylor suspects the straggly bloom is the result of insufficient chilling hours this past winter.
His Sunlands have set an average number of nuts, while his Vinas and Hartleys have set more nuts than last year. Meanwhile, the nut set on his Tulares is down from 201, and it’s too early to tell for the Chandlers.
Taylor is reserving any crop size estimate until after the June drop. “Some years it can be a very heavy drop,” he says.
The unusually dry weather, which began at the start of this year, continues. The last measurable precipitation in his orchards was .01 inch of rain on April 16. Eight days before that, a quarter-inch of rain fell.
“That was the last of the storms we’ve had this spring,” he says. “We’ve had very little rain this year, and everyone is concerned about it.”
Although light rainfall in March prompted Taylor to make blight sprays, the dry weather has minimized disease pressures in his orchards. At the same time, though, he expects it will drive up his irrigation costs. All his water for his impact sprinkler systems comes from wells.
“Already this season we’re into very frequent and long irrigations,” he says. “With the dry weather likely to continue, I expect my power bills for pumping water will exceed last year’s by quite a bit.”
Because Taylor is planning on an unusually hot summer, too, he’ll be treating his trees with Surround crop protectant to reduce against sunburn. He may even make a second application later in the season.” Some years, like 2011, that hasn’t been necessary, he notes. Last year, he put on sunblock late in the season and in time to help protect the trees from hot weather shortly before harvest.
He’s ready to respond to any walnut husk fly pressure this season. This tough-to-control pest that damages kernels and stain shells, is becoming an increasingly greater threat in his area. His Hartleys and Vinas are very susceptible to husk fly damage;
About the size of a housefly, husk flies have one generation a year overwinter as pupae in the soil. They emerge between late June and early September. Maggots hatch from eggs laid below the surface of the husk, where they feed. When mature, the maggots drop to the ground and burrow several inches into the soil to pupate. Most emerge as adults the following summer. But some may remain in the soil for two years or longer.