“Although our 2009 walnut crop is at the infancy stages of development, the potential is there for a decent walnut crop this year,” says veteran Sacramento Valley walnut producer Dave Keyawa.

He and his brother, Ron, own Keyawa Orchards, Inc., which includes about 1,500 acres of producing walnuts, 250 acres of almonds and 5 acres of pecans in California’s Butte and Glenn counties. They also process about 7,000 tons of walnuts annually through their Tri Counties Walnut Hulling facility located in Ord Bend.

One factor that will determine crop size will be the amount of pistillate flower abscission (PFA) that develops. The condition, which typically occurs two to three weeks after bloom, already has affected some of their early varieties, such as Serr, Chico, Vina, and Ashley. The problem is associated with high pollen loads during bloom, and it varies year to year.

“Because PFA is enhanced by dry weather, its appearance this year isn’t unexpected,” Dave says. “During bloom in wet weather, the pollen is naturally removed by the rain.”

Mid- to later varieties, such as Tehama, Howard, Hartley and Chandler, are showing very little PFA, but it’s still a little early to evaluate, he says.

“With the recent storms, however, the later varieties may suffer from lack of pollen, as the intensity of the storm systems may remove too many catkins. While this can cause nut drop, usually it’s not as significant as PFA.”

One of their water districts is allocating only 10 percent of normal water this year, but a new well should enable them to meet water requirements on that particular ranch.

Dave has been seeing moderate to heavy coddling moth numbers since trapping started in March. He treats his early varieties with a relatively new pyrethroid. “It seems to lessen the flare in mites when used early and is compatible with copper and Manex, which we use to control blight,” he says.

“We’ll also be treating for sunburn with products containing mostly kaolin clay. When properly applied, it reduces the amount of sunburned nuts, which not only results in more harvestable nuts, but also lessens the potential of secondary pests, such as navel orangeworm. However, sunburn prevention products are not standalone — you also need adequate water. That’s the primary defense against sunburn.”

Dave expects to treat for other pests, such as mites, in late May or June and for husk fly in late July through September.

“We’ll treat fields with ethephon to advance harvest,” he says. “I apply it in late August through September to improve crop quality and help with harvest coordination.”