Sac Valley Orchards

Walnut production costs remain elevated, and overall profitability continues to hinge on how well growers can manage key cost drivers. With margins still tight, understanding where costs have increased over time could benefit growers in identifying areas where savings may be possible.

Crown rot and root rot caused by Phytophthora species are diseases of great concern for walnut growers. Many people believe that irrigating with surface water puts your trees at risk of Phytophthora, and that irrigating with groundwater is the best way to prevent these diseases. However, a recent study of Phytophthora in irrigation water and orchard soils tells a different story.

A lot of factors impact the planting decision. Once a site is selected, the three critical decisions in establishing a new walnut orchard are variety selection, rootstock selection, and tree/row spacing. The spacing should be determined after the variety and rootstock are chosen because that combination will determine the ultimate size of the tree, along with the soil type and orchard management. Rootstocks are the foundation of a walnut orchard. Selecting one that tolerates or resists site problems, while providing vigor for optimum tree performance, is key to orchard productivity, health, and longevity.  As pesticide and fumigant options become more limited and restrictive, rootstocks that resist or tolerate soilborne pathogens offer a pathway to long-term management.

Curt Pierce, UCCE Irrigation and Water Resources Advisor, Glenn, Tehama, Colusa, and Shasta Counties Deciding when to start irrigating your prune orchard can be difficult. The weather starts to get warm, the soil surface looks dry, and we want to make sure our trees have the best start to the season that we can give them. However, ...

Over the past few years, Sacramento Valley Orchard Advisors have received several calls about flatheaded borer damage concerns in walnut orchards. While most of those farm visits were found to be unrelated to flatheaded borer, it certainly underscored the need for awareness and accurate diagnosis of flatheaded borer and other problems.