The pistachio orchards of S&J Ranch in Madera County started blooming the first week of April, about the normal time, says Kevin Olsen, vice president of S&J Ranch, a farm management company that also produces citrus and other permanent crops in the San Joaquin Valley.
The start of bloom followed an usually dry winter. In fact, for the first time in several years, S&J Ranch turned on its micro-sprinklers in January and February. Last year, no irrigation was needed until the end of April.
“Our surface water allocations are down this year,” Olsen says. “But, we get much of our water from wells and the groundwater supplies seem to be holding up.”
This past winter also featured more than adequate chilling for flowers and leaf buds to develop normally this spring. Between Nov. 1 and Feb. 29, CMIS weather station data for the county shows 1,544 cumulative hours of temperatures below 45 degrees and 1,146 hours of cumulative temperatures between 32 and 45 degrees.
“That’s a lot of chilling hours for us,” Olsen says. “Normally, we get somewhere around 950 to 1,000 chilling hours.”
This is an on-year for the alternate-bearing pistachio trees. “There are a huge number of fruit buds on the trees this year,” he says.
How many marketable nuts are produced will depend on bloom quality and pollination, he says. Typically, pistachio bloom lasts 10 to 14 days, but it could linger longer this year due to cool, wet weather. That could lower pollination success and increase the threat of both botrytis and botrysphaeria.
Last year, botrysphaeria pressure was a little higher than it has been in recent years, Olsen says. Because of the rainy weather during bloom this year, he treated for both botryosphaeria and botrytis. He may spray a couple more times this season for botrysphaeria, as well as alternaria, depending on weather and disease levels.
After nut set, he’ll begin monitoring for lygus bugs, leaffooted plant bugs and stink bugs. “Last year, we had a fair amount of pressure, in general, from these insects,” he says. “We do a lot of monitoring of population levels so we don’t spray unnecessarily.”
S&J Ranch pistachio trees range in age from seven years old to 40 years. The orchards are located on the east side of Madera County where boron levels in the soils are characteristically low. He applies boron in the spring, either as a broadcast treatment or, if possible, in combination with a herbicide application to save a trip through the fields.