Chilling Hours Update 2021-Yuba City
Because there is not a CIMIS station close to Yuba City, Janine Hasey calculates chilling based on a temperature recorder at the UCCE office in Yuba City. Chill data will be updated weekly. Continue reading
Author Archives: Janine Hasey
2022 Walnut Crop Loss and Poor Nut Quality – What happened?
There are those years we like to leave behind, and 2022 will be at the top of the list for the walnut industry. Read for more information on the most likely environmental conditions that led to 2022 crop damage and subsequent yield losses and poor nut quality. Continue reading
Spring- Preparing for Extreme Events: Frost
An April frost can have potentially devastating results. The last severe spring frost occurred in April 2008. During a frost event, there are many factors that influence whether or not frost damage will occur in a particular orchard. This article provides guidelines should a spring frost occur. Continue reading
Advisor Retirement
I am retiring on July 1st after nearly 38 years working for UC Cooperative Extension and over 36 years as an Orchard and Environmental Horticulture (EH) Advisor in Sutter-Yuba Counties. What an honor to work with all of you growers, PCAs, and others in the Ag industry, and such a privilege to collaborate with so many talented UC colleagues solving challenging problems together. Continue reading
Mesophyll Collapse
We have been seeing walnut leaves showing browning (necrosis) on the leaf area between the veins in some orchards since about mid-May. Sometimes the leaves will then twist and defoliate in very severe situations. We call this problem mesophyll collapse and believe it is a physiological problem associated with sudden temperature changes. Continue reading
Chilling Hours Update 2019 – Yuba City
How are we doing on chill so far this year? Because there is not a CIMIS station close to Yuba City, Janine Hasey calculates chill based on a temperature recorder at the UCCE office in Yuba City. Chill data will be updated weekly. Continue reading
Cost and Expense Considerations in a Lean Price Year
Since last summer, coffee shop talk has been centered on the low price of walnuts. We all hope to see improvement in pricing soon. Even if prices increase, there are cultural and pest management options to improving your profit margin. … Continue reading
Early Walnut Tree Training: How to Handle Different Nursery Products
Updated 10/25/18; Originally posted July 2018. Janine Hasey, UCCE Tree Crops Advisor Sutter/ Yuba/ Colusa Counties; Bruce Lampinen, UCCE Walnut Specialist, UC Davis; Katherine Jarvis-Shean, UCCE Orchard Advisor Sacramento, Solano & Yolo Cos. Early walnut tree training begins at the time of … Continue reading
Chilling Hours Update 2020 – Yuba City
How are we doing on chill so far this year? Because there is not a CIMIS station close to Yuba City, Janine Hasey calculates chill based on a temperature recorder at the UCCE office in Yuba City. Chill data will be updated weekly. Continue reading
End of 2017 Season Flooded Orchard Damage Update
This article briefly reviews our observations since early June in orchards either directly flooded in the river bottoms or those indirectly flooded with standing water for months via under-levee seepage. Continue reading
Impacts and Recovery on Walnuts from 2017 Flooding
Janine Hasey, UCCE Farm Advisor, Sutter/Yuba/Colusa Counties, Greg Browne, USDA Plant Pathologist, UC Davis, Astrid Volder, Plant Sciences, UC Davis and Bruce Lampinen, UCCE Walnut Specialist, UC Davis 2017 brought unprecedented high and fluctuating water flows in the Sacramento and Feather Rivers, damaging … Continue reading
Summer Flooded Orchard Damage Update, Part 2: Management Considerations
In 2017, high and fluctuating water flows, unprecedented for their duration, passed through the Sacramento and Feather Rivers. Orchards were hurt by these flows due to direct flooding, indirect flooding via under-levee seepage, and loss of land through river bank erosion. Many orchards had standing water from January through mid-May. In other orchards, ditches overflowed with nowhere to pump water out. Part 2 of this article discusses best practices to consider for orchard management after a flood event. Continue reading
Summer Flooded Orchard Damage Update, Part 1: Observations and Research Plans
In 2017, high and fluctuating water flows, unprecedented for their duration, passed through the Sacramento and Feather Rivers. Orchards were hurt by these flows due to direct flooding, indirect flooding via under-levee seepage, and loss of land through river bank erosion. Many orchards had standing water from January through mid-May. In other orchards, ditches overflowed with nowhere to pump water out. Part 1 of this article details our observations on flooded orchard damage as of early June and current research plans. Continue reading
Walnut Trees in the Nursery Trade: Terminology, Propagation, Availability, & Pest Interactions
Updated February, 2020. Originally posted June, 2016. Janine Hasey, Chuck Leslie, Wesley Hackett, Pat J. Brown, Andreas Westphal, Michael McKenry, Greg Browne, & Dan Kluepfel. Helpful terminology in understanding walnut plant material: Cultivar (cultivated variety) – A named group of … Continue reading
Points to Consider in Prevention of Crown Gall
The Paradox hybrids (Juglans hindsii x Juglans regia) commonly used as walnut rootstocks are highly susceptible to Crown Gall caused by the common soil-borne bacterium Agrobacterium tumefaciens. Here we present information from our quest to develop a robust comprehensive approach to crown gall prevention. Continue reading