By the last week of April, developing almonds in Stanislaus County had reached the clear jelly stage of filling.
“We’re probably running a good week behind usual,” says Roger Duncan, University of California pomology farm advisor for the county. “But, it’s hard to know what ‘usual’ is any more. Relatively speaking, the crop is making normal progress.”
Should the cool weather continue, other development stages for this year’s crop, including hull split, harvest, and insect activity, would also be delayed. That wouldn’t be a problem unless there’s a repeat of last year’s late harvest start and early start of fall rains.
“That caused some real headaches for growers with the latest varieties to mature,” Duncan says.
Nut set in the county’s orchards has been is spotty, but overall, the crop looks pretty good, he says. The variation among orchards reflects differences in such factors as time of bloom, tree nutrition and last year’s crop load.
“Overall, it appears that many of the orchards will have average yields, while some will have better than average production,” Duncan says. “As you travel farther south in the San Joaquin Valley, where they didn’t get as much rain this spring, I understand the crop is better.”
As in other almond-growing areas of the state, cold temperatures combined with wet spring weather increased the incidence of bacterial blast. The blossom blight is caused by the bacterium, Pseudomonas syringe, the same one that causes bacterial canker and bud drop.
“The problem was worse this year than I have seen in many years,” Duncan says. “It’s particularly a problem in low spots or where cold air drains into an area, or in orchards with a tall cover crop. It’s difficult to control with a spray because fungicides are ineffective in combating a bacteria-caused disease.”
Currently, Stanislaus County growers are irrigating orchards and continuing fertilizer applications. Over the past few years, more of them have been switching their potassium source from potassium sulfate (also called sulfate of potash or SOP), a dry powder banded down tree rows in the fall, to a liquid material, potassium thiosulfate (KTS), applied through drip or micro-sprinkler systems during the growing season.
The liquid fertilizer probably offers a more efficient way to get more potassium into the tree per pound of material applied, Duncan says. KTS is roughly twice the price per pound of potassium.
“The question is, whether or not injecting KTS is twice as efficient in getting potassium into the tree compared to the dry, banded method of potash application,” he says. “University of California trials are currently under way to determine that.”