Three weeks after catkins fell at the end of March, the nutlets on Darren Ventura’s walnut trees in Stanislaus County had grown to about one-quarter inch in diameter.
“The nut set looks pretty good and is similar to last year when we had an average size crop,” Ventura says. “This year, the Chandler (variety) might look a little better than the Tulare’s.”
Ventura manages 80 acres of walnut trees, split evenly between these two varieties, along with 240 acres of almonds for the Hudelson Company, located near Modesto, Calif.
The walnut orchards and a 100-acre block of almonds are located in the Modesto Irrigation District (MID). The remaining almond acreage receives surface water from the Oakdale Irrigation District (OID).
“Right now, the outlook for this coming irrigation season is really good,” Ventura says. “After four years of drought, we finally had an average amount of winter rainfall. Our water allocation for both districts this year has gone up.”
His MID allocation has increased from 18 acre-inches last to 30 acre-inches this year.
“This year, water deliveries from OID are based on data including soil characteristics and weather conditions to determine when and how much water the trees should need,” Ventura adds. “We get this amount and no more.”
In 2015, dry soil conditions prompted him to begin irrigating the trees in early March. This year, due to improved soil moisture levels, he started irrigating with his solid set and low volume systems in mid-April.
The nearly two inches of rain that fell the weekend of April 9-10 added to his soil moisture readings. Ventura uses a soil probe and a potentiometer to monitor the soil drying rate. Often, that’s every other day early in the season.
Usually, codling moth pressure in his orchards isn’t on the high side. Ventura uses trap counts to monitor populations and applies sprays as needed based on degree days. He expects the first codling moth flight in the walnut blocks this season starting the first week of May.
He rates walnut husk fly as the most worrisome insect threat to his walnut crop. Stands of black walnut trees growing along the banks of the Stanislaus River next to his walnut orchards drop an ample supply of nuts for this pest to overwinter.
“Last year, walnut husk fly got a little bit out of control, especially in our Chandlers,” Ventura says. “But, we’re starting to get a handle on it.”
“In addition to winter sanitation, we start our insecticide spray program in May, based on when we trap the first adult females. Then we usually spray the trees every 10-14 days until hull split, when husk flies are no longer a threat to the nuts.”
Ventura views the dramatic price downturn in the walnut market, which began when prices began sinking last September to levels in 2016 which are less than what they were a year earlier, as necessary medicine to remedy an imbalanced market.
“We’ve had market fluctuations before,” the walnut grower notes.
In 2008, walnut prices dropped to about 50 cents a pound; making it hard for some growers to pay the bills. Ventura says higher prices in recent years were great but were inflated and “sustainable.”