A shortfall of winter chilling hours may be taking a toll in some pistachio orchards

A shortfall of winter chilling hours may be taking a toll in some pistachio orchards

“The uncertainty of the blanks is still overshadowing everyone’s crop prediction,” says well-known pistachio consultant Carl Fanucchi, Fanucchi Diversified Management, Inc., Bakersfield, Calif.

As the 2014 season got underway, many pistachio growers saw their female trees, such as Kerman, Golden Hills and Lost Hills, flowering earlier than the males, like Peters and Randy.  Most observers attributed this to an insufficient number of chilling hours over the winter to release the trees from dormancy. This poor synchrony raised concerns that pollination success may have suffered, resulting in more blank nuts at harvest.

Whether or not that’s actually the case once growers start bringing in the crop – which is expected to begin the last week of August in the south end of the San Joaquin Valley – may depend on the make-up and location of the orchard.

“The uncertainty of the blanks is still overshadowing everyone’s crop prediction,” says well-known pistachio consultant Carl Fanucchi, Fanucchi Diversified Management, Inc., Bakersfield, Calif. “I’m probably more optimistic than most growers and field men in that the Kern County crop in the lower elevations, which is the bulk of my consulting area, looks fairly normal for blanks. The maturity will be prolonged because of the extended bloom period, caused by the erratic chilling received last winter.”

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Meanwhile, farther north in Fresno County, University of California Cooperative Extension farm advisor Gurreet Brar sampled nuts from five West Side pistachio orchards on Aug. 12. None appears to have suffered any water stress this year.

“In Kerman orchards where Peters was the only male, some clusters had more than 50 percent blank nuts, with the average blank percentage around 30 percent,” he reports. “However, in Lost Hills and Pete 1 orchards having other males besides Peters there were fewer blanks.”

Pete 1 is a new cultivar that has shown a high percentage of blanks in previous years. In the one orchard Brar sampled that included Pete 1, 30 percent of the nuts on this cultivar were blanks. That compare to the 15 percent to 17 percent of blanks he found on Lost Hills.

The overlap of bloom of Randy and Chico males with many cultivars this year was good, Brar notes.

“Nut blanking can also occur during the nut-fill stage due to lack of water and nutrient availability, which is very critical during this period,” he adds.

The day Brar collected his samples, he noted that hulls on Lost Hills trees were slipping off easily, while hull split was just starting in Kerman. The growers he visited were planning to start harvesting during the first week of September, Brar says.

Hulls started to loosen in Fanucchi’s area of Kern County the first week of August.

“I know a lot of harvesters will be starting as early as the 25th of this month,” he says. “We’re all anxious to see what we really have out there. Most growers have managed to adequately irrigate the pistachios, with some very expensive water purchases.

“Many almond orchards are looking pretty rough as a result of growers having to use a lot of unsuitable, saline well water.”

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