Pistachio split bloom could mean double harvest

This could be a double harvest year for some pistachio growers — at least that’s how veteran pistachio grower and consultant Carl Fanucchi, Fanucchi Diversified Management, Inc., Bakersfield, Calif., sees the crop shaping up.

That’s his assessment from the chilling hours this past winter and unusual leaf-out patterns and a split bloom in some areas this spring.

Reports indicate that pistachio orchards had well over 1,000 chilling hours. “But, did we have as much chilling as we thought?” he wonders.

Despite years of research on pistachios, chilling is a tough issue to nail down. The quality of the chilling may be more important in affecting crop outcome than the actual number of chilling hours, he believes.

“Do 100 hours below 45 degrees in fog have the same effect on the trees as the same temperatures and duration on a clear day?” Fanucchi asks.

“There is some thinking that sunlight may affect the physiology of the tree differently than a cloudy day, even though the ambient temperature is the same. No one really knows yet the magic number of chilling hours for pistachios and how to measure it.”

This year the leaf-out and bloom of pistachios — long thought to be related to chilling hours — point to a possible double harvest, he says.

The leaf-out and bloom in many orchards in Kern, Kings and Tulare counties were perfectly normal, he says, but there were a number of spots where he describes the leaf-out as “weird.” Some parts of a tree leafed out way ahead of the rest of the tree, he says. “And these were trees where no oil had been applied to help mitigate lack of chilling. Also, these areas experienced big up-and-down swings in temperature, which caused a split bloom. In some cases, there was a good three-week spread in the bloom.

“If the crop ends up looking as big as it does now, pistachio growers with substantial acreages of older trees will probably be harvesting their orchards twice this year to get optimal quality,” Fanucchi says.

TAGS: Tree Nuts
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