What is in this article?:
- California pistachio growers were served up advice on topics that ranged from new regulations on food safety and nitrates in ground water, an epidemic year for navel orangeworm in 2012, a new biopesticide to reduce aflatoxins and new cultivars that could hold promise.
NOW, mealy bug
Other presentations at the pistachio day included:
• Joel Siegel, with the USDA’s Agriculture Research Service in Parlier, talked of a “blowup year” in 2012 for navel orangeworm despite a record statewide pistachio crop of more than 555 million pounds.
Siegel looked at three years of heavy infestations for the pest: 2001, 2007 and 2012. He said research indicates the number of degree days for those years was high, meaning that warmer weather could be “fuel for the fire” of an infestation.
Moreover, he said, growers who have had no damage in certain years may relax their management efforts. “It’s man’s fallible nature,” he said. He added that the timing of sprays for the pest is critical.
Damage from navel orangeworm was highly variable in the Central Valley, with Tulare County hit significantly more than Fresno County last year.
• Craig Kallsen, UC farm advisor for Kern County, talked of new pistachio cultivars that include Golden Hills, Lost Hills and Kalehghouchi.
The male “Randy” is the preferred pollenizer for both Golden Hills and Lost Hills.
Kallsen gave some advice on pruning those two varieties differently than the common Kerman variety, for example not tipping the trees late. Both of the newer cultivars are harvested 10 days to two weeks earlier than Kerman. Monitoring for pests should also start sooner in those newer varieties, he said.
• David Haviland, UC advisor in Kern County, talked of problem with mealy bug management in pistachios.
He said it is important for growers to distinguish between the Gill’s mealy bug in pistachios, which can damage trees, and the grape mealy bug, which does not. The grape pest, he said, commonly “goes away, bio controls get it.”
Haviland said now is a good time to monitor orchards for the Gill’s mealy bug, which is indicated by cotton candy-like masses on the trunks of trees.
He said the pest causes kernels that are smaller, nuts that don’t split and sooty mold and honeydew.
Pesticides that can have varying degrees of effectiveness in controlling the pests include Centaur, Movento, Assail, Admire and Sevin.
Haviland said it is important to wash equipment and bulk containers to avoid spread of the pest.
• Beede recommended at least annual leaf tissue sampling as a way to get a handle on nutrient use.
He said that the time of greatest demand for nitrogen is when the kernel is filling. “Don’t put on nitrogen too early,” he said. He said limited amounts should be applied during the spring flush in late March to mid-May.
Beede also said the greatest demand for potassium comes during kernel fill.