Arizona pistachio grower Steve Seplak expected his production would go down in 2011 — an off-year for the alternate bearing crop. He just didn’t expect it to drop as far as appeared likely in the early days of August.
One of about 30 pistachio growers in the Sulfur Springs Valley near Bowie, Ariz., he grows about 20 acres of pistachio trees in his SAS-Z Nuts orchard near Willcox, Ariz. He also grows a small variety of fruit: apples, apricots, nectarines, pears, peaches, and plums.
Seplak bought the orchard 10 years ago and estimates the pistachio trees are about 16 years old. Between the on-years and the lower-producing off-years, the trees yield an average of 1,850 pounds of nuts per acre annually. In a good year, that can reach 2,500 to 2,850 pounds.
Last year was an exceptionally productive one; his yields shot up to 3,550 pounds per acre. The weather may help explain that, he says.
“Winter before last, we had a lot of rain and a mild spring, and everything came out strong. Even the fruit orchard crops were out of this world.”
This year, however, Seplak doubts that he’ll bring in much more than about 1,500 pounds of nuts per acre when he harvests the crop, probably beginning the first week of September.
“I can go through the orchard and find one tree loaded with nuts, like last year,” he explains. “But, the next two or three trees may have only two or three clusters, with only four nuts in a cluster.
“I don’t think the trees sprouted any new growth last year to support this year’s crop. All the trees’ energy went into producing nuts. I think the trees over-produced and needed to rest this year.”
Also, the trees had no rain for this year’s crop from the middle of last October until the last week of July, when the first summer monsoon dropped about 2 inches of rain on his orchards.
Water for his micro-sprinkler systems comes from wells. The dry winter forced him to advance the normal start of his irrigation season from mid-April to late March.
Seplak’s production prospects contrast sharply with those he saw during a tour of several California pistachio orchards in the last week of July. “They’re going to have a good crop this year,” he says.
The lack of rain this spring may have had an upside for him by keeping stink bug numbers down. “Usually, they’re a problem,” he says. “But, so far, we haven’t had to apply any pesticide to control them.”
Any grasshoppers probably won’t show up until about the third week of August.
Typically, diseases are minimal. “This area has at least 600 hours of below-freezing temperatures during the winter and that tends to pretty well hold down any disease.”
Much of Seplak’s attention is now focused on the weather forecasts and the two-month monsoon season, which usually ends by late August. Depending on hurricanes in the Gulf of Mexico and the winds, wet weather this month could lead to a pre-harvest leaf drop. Last year, one monsoon rain soaked his trees with 5.5 inches of rain.
“If the humidity gets high and moisture gets in the trees, the leaves tend to wither and can fall off as early as the first week of September instead of mid-October, when they normally fall,” Seplak says. “My big concern now is just getting the crop to harvest.”