Catkins on the 2,200 acres of walnut trees in Lake County, Calif., were very visible by the end of the third week in April, says Rachel Elkins, University of California Extension pomology farm advisor for Lake and Mendocino counties.
At that point, the pollen load was just starting, the trees were beginning to leaf out and the pistillate buds had not yet opened.
Even though most of the county’s walnuts are at elevations ranging from nearly 1,400 feet to 2,200 feet or higher, that’s still a little later than normal, Elkins says.
As in other California walnut-producing areas, the 2011growing season started out cool and wet, following a cold, rainy winter. Rainfall totals for Lake County ranged from 8 to nearly 20 inches in March and from about 33 to 60 inches or more, depending on location, since last July 1. If the rains continue into May, growers could begin seeing some walnut blight as pistillate bloom emerges. That’s the only disease of any real significance, except for deep bark canker in the Hartleys.
“I wouldn’t be surprised if we have a little this year,” Elkins says. “It occurs only very intermittently here, and isn’t the concern that it is in the Sacramento Valley, because we grow only the late-blooming varieties. We had some blight last year, so the inoculum could be out there in some orchards, but most growers here don’t even own a sprayer.”
In fact, she says, a delayed bloom this year could reduce the disease threat, since rainfall normally declines after May 1.
The three main varieties grown by Lake County farmers — the older Franquettes and Hartleys and the newer Chandlers, all of which bloom late — also help reduce the incidence of walnut blight.
Organic production is a key factor in the county’s walnut economy, Elkins notes. “The premiums offered organic growers have been very good, but dropped last year, due we think to increased imports of organic walnuts. Our growers would like to see those premiums stay high or even increase.”
The strong walnut market of the past few years has led to an expansion in Lake County’s Chandler acreage.
“In some cases, that represents new orchards,” Elkins says. “But, most of the new plantings have replaced pears. Because of low pear prices, some farmers are looking at alternatives. Walnuts seem a better choice now than wine grapes, because the trees are not as expensive to establish and maintain.”