Walnuts Archives - Page 2 of 9 - West Coast Nut



Predicting and Managing Walnut Blight

Timing spray applications to protect walnut trees from blight infection can be done based on orchard history with the disease and monitoring buds along with the forecasting tool Xanthocast. (more…)

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Economic Benefits of Using Improved Walnut Rootstocks

Walnut production is a long-term commitment of resources in land, labor and management. Because of the lag time from field preparation and planting to first harvest, walnut production is a fiscally demanding endeavor. During production operations, orchard management is a critical factor for improving yield; this includes tree protection from soil-borne maladies. Soil-borne plant diseases include plant-parasitic nematodes (root lesion nematode, Pratylenchus vulnus, root-knot nematodes, Meloidogyne spp.), crown gall (Agrobacterium tumefaciens), and Phytophthora root and crown rots (Phytophthora spp.). Among the biotic stresses there is also the so-called “replant problem”, where the walnut...

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In Search of Chandler 2.0

It’s been more than 40 years since the University of California’s Walnut Improvement Program released a variety as successful as Chandler, which today comprises more than a third of California’s walnut acreage and is the standard to which all others are compared. That’s not for lack of effort. As Chuck Leslie, who has worked for the program for 35 years, said: “Chandler is a tough competitor.” Because of its good yields, premium quality and desirable growth characteristics, even today, California growers continue to plant Chandler in high numbers. In 2017, for example, there were more than 16,000 acres of nonbearing...

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Regional Board Rules Put Walnut Hullers Under the Microscope

Over the past year, the agricultural industry has observed as the Central Valley Regional Water Quality Control Board (Regional Board) make sweeping changes to discharging regulations specific to agricultural regions and specific processing facilities.  With the passage of SB 200 – Safe Drinking Water Fund (Monning), as well as the passage of the Central Valley Salinity Alternatives for Long-Term Sustainability Program (CV-SALTS) by the Regional Board, water quality and discharges from agricultural operations are now even further under the microscope.  Late last year, a notice was sent to interested stakeholders that the Regional Board would be taking up a vote...

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The Next Generation of Walnut Rootstock Aims at Resistance to Soil-Borne Pathogens

A multi-disciplinary collaboration is underway to develop and deploy walnut rootstocks with resistance to the major soil-borne pathogens, specifically crown gall (Agrobacterium tumefaciens), Phytophthora root/crown rot (Phytophthora spp.), and lesion nematodes (Pratylenchus vulnus). According to Dr. Ali McClean with the USDA’s Crop Pathology and Genetics Research Unit at UC Davis, a significant proportion of the walnut industry uses either seedling or clonal ‘Paradox’ rootstocks, which is susceptible to disease caused by several soil-borne pathogens. McClean said since there are limited preplant and post-plant management strategies for these stresses, rootstocks with elevated levels of genetic resistance/tolerance to these pathogens offer the...

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