Walnuts Archives - Page 5 of 9 - West Coast Nut



Preparing Walnut Trees for Winter

Fully dormant mature walnut trees can tolerate temperatures into the low 20’s or below, so long as trees are in full dormancy, according to University of California Cooperative Extension (UCCE) farm advisor, emeritus, Wilbur Reil. While it’s tempting to push young tree growth as long as possible in the fall, it’s also risky. Freezing temperatures can cause die back in young trees, sometimes almost to the roots. Freeze events can also severely damage trees in mid-winter if the soil is dry. Fully dormant walnut trees can withstand temperatures well below freezing, but young trees are more susceptible to damage. It...

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Grower Profile: Vanella Farms

In 1968, Bob Vanella bought ten acres in Chico, California. His son, Ryan Vanella recalls the story of when Bob came to look at the property with a house and a huller in the back. He had always wanted a huller. After he bought it, he went to tell his wife Sue, that he bought a huller with a little house in the front. She of course asked about the house. In which he replied “I don’t know, I didn’t look at the house. But there is a huller in the back”. Sue always knew Bob wanted to be a...

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Nitrogen in Walnuts—What, When, Where and how Much

To know how to correctly use nitrogen in walnut orchards, you first have to know some of the basic principals of nitrogen, according to Katherine Jarvis-Shean, University of California Cooperative Extension area orchard systems adviser for Sacramento, Solano, and Yolo counties. Jarvis-Shean shared this information during the Nickels Soil Lab Annual Field Day in her presentation—Nitrogen in Walnuts: What, When, Where and How Much? Nitrogen Principals Jarvis-Shean said growers have a few different forms of nitrogen as options of use in their agriculture systems. “Nitrogen is one part of soil organic matter, one part of urea, as in ammonium, and...

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The Call of the Wild: Taming the Sleeping Dragon Bot of Walnut

In the last decade or so, we observed an unusual high incidence of diseases caused by fungi in the family of Botryosphaeriaceae known as Bot cankers and blights. It was in 1985 when Dr. Michailides as a postdoctoral researcher started working with Bot of pistachio which initially was discovered in a few orchards in Butte County and was very severe in the first pistachio commercial orchard planted in Durham California. It took about 10-12 years until the disease became an epidemic among the pistachio growing acreage from the north (Butte, Glenn, and Tehama Counties) and Central (Merced, Madera, and Fresno...

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Ethephon Applications

Two objectives in using the plant growth regulator Ethephon in walnut production are an earlier harvest and a more efficient harvest. Ethephon, sold as Ethrel, is converted to ethylene a gas that is responsible for changes in texture, softening, color and other maturation processes. The systemic properties of Ethephon allow it to penetrate plant tissues and decomposed to ethylene. In walnuts, ethylene accelerates walnut hull cracking and separation from the shell, advancing harvest by a week to ten days, depending on season and variety. Harvest efficiency is improved as more uniform maturity is achieved and only a single shake is...

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