In the first full week of April, catkins began pushing out in the walnut orchards of grower Dan Cummings, Chico, Calif. — not much later than usual.
With a forecast of continued wet weather, he planned to begin blight sprays inthe following weeks. That’s not unusual, either.
“We’ve had wet springs for the past few years and have been applying roughlytwo sprays each season,” he says.
As owner of Cummings-Violich Orchard Management, Inc., he manages several thousand acres of walnuts and almonds in the Sacramento Valley.
Despite rains this past winter, his crews were still able to get into the orchards with pruning towers and mechanical rotary hedging. They finished that work early this month and are now mowing to control weeds.
Last month, Cummings began his annual fertilization program, applying 250 pounds per acre of sulfate of potash. This month, he’ll apply nitrogen in the form of ammonium sulfate and will follow with CAN-17 and UN-32. This summer, he’ll come back with another potassium treatment, fertigating orchards with 15 to 20 gallons per acre of KTS.
Cummings combines his fertility program with precisely-timed irrigation to reduce sun burn of walnuts by encouraging vigorous growth of foliage to shade the nuts. Operation of solid set or micro-sprinklers is tied to the water status of the trees and the soil.
At one time, Cummings used conventional tools, like pressure bombs and Irrometers,to gauge the trees’ water needs and to determine when to irrigate. Four years ago, he replaced that method with a PureSense soil and climate monitoring system.
“It reports soil moisture every 15 minutes at 4-inch intervals to a depth of 5 feet,” he says. “We’re trying to be as specific as we can with irrigation. This technology allows us to meet the water needs of trees as closely as possible “
Later this year, Cumming will use a different type of technology to add a new twist to his codling moth control program. For the first time, he’ll hang pheromone-emitting puffers in the orchards to disrupt mating. The idea is to reduce the need for pesticides to control the moths.
“I like this soft approach to codling moth control,” he says. “Our neighbors have been using puffers, and I believe puffers are more effective, if they are used area-wide rather than in just some orchards here and there. I hope we can expand this practice in the future.”