Orchard Notes: June 2023

Maintenance Checklist for July

Luke Milliron, UCCE Farm Advisor, Butte, Glenn and Tehama Counties

Franz Niederholzer, UCCE Farm Advisor, Colusa, Sutter and Yuba Counties

Becky Wheeler-Dykes, Orchard Researcher, Chico State

Katherine Jarvis-Shean, UCCE Farm Advisor Sacramento, Solano & Yolo Counties

Jan economic risk in years with light crop and larger fruit while sunburn may be a higher economic risk in heavier crop years with less extra-large fruit. To see more information on sunburn (“blue prune”) click HERE.


  • Preventing defoliation: Continue monitoring for late summer (preharvest) outbreaks of rust and spider mites. Infestations of these pests can cause leaf drop that weakens trees, reduces sugar levels, and slows harvest. In very hot weather, mite populations can double in a week.
  • Fruit brown rot: Clustered fruit is more vulnerable to brown rot infections as harvest approaches.
  • Monitoring fruit maturity: Fruit should be mature in roughly 30 days after the first color shows on the suture. Begin measuring fruit internal pressure once fruit shows color.
  • July leaf samples: Mark your calendar for July leaf sampling.
  • Clean up orchard ahead of harvest for faster operation.

Meet Zach Bagley

Zach BagleyManaging Advisor of Production Research & Partnership, Zach Bagley works in collaboration with Agricultural Research Consultant Gary Obenauf and provides communications counsel to the CPB team. In this interview, Zach shares some of the latest from our production research and how the breeding program will likely benefit growers in the future.

1. Welcome to the team! Tell us a little bit about yourself.

Thank you to all. I’m looking forward to getting to know California Prune growers, and the industry, better in the coming months. Working alongside the CPB team, a dedicated group of professionals, to tackle the challenges of the prune industry is energizing and welcomed. It’s a tired adage, but the phrase, “Drinking from a fire hose,” does seem apt for the experience of jumping into this role in this industry. There is much to learn and understand and I can’t wait to dive in.

For the last 10 years I’ve been working in the processing tomato industry here in California. I started off managing by-products and working as a grower field representative for the same operation (Olam Williams); in 2017 I transitioned to the role of Managing Director of the California Tomato Research Institute. As the Managing Advisor of Production Research and Partnerships for the CPB I expect to bridge these two roles – bringing best practice exchange in the areas of research prioritization, grower relations, research finding communications, researcher engagement and contracting, and direct grant writing.

As an alumnus of Purdue University, UC Davis, the California Agricultural Leadership Foundation (Class 46),  and a returned Peace Corps Volunteer (Uganda, 2009-2011), my biggest and most important learning curve of the last 10 years has been becoming a father of two daughters who are now 7 and 4. When I’m not thinking about prunes or tomatoes, I’m singing to the “Frozen” soundtracks while driving to a dance or soccer practice, or a family camping trip in the beautiful California Sierras.

I’d like to look back at some point and say, as the author Wendell Berry wrote in his book, “A Place on Earth”, “I can tell you that all of my life…I’ve been inspired by this place, and by what I foresaw or hoped, I could do in it. I’ve lived my life the way a hungry man eats.”

2. What current production research projects are most compelling from your perspective?

Agricultural production in California is in the midst of significant disruption. Challenges for both growers and handlers abound water and labor availability, restrictions on crop protection products, availability of cost effective and consistent sources of energy for processing, unpredictable weather, and pest and disease pressures of increasing diversity, density and impact; to name a few. To maintain and grow the scale of impact of our research we’ve got to build on our past investments and successes in addition to cultivating new partnerships between the industry, researchers, and outside funding bodies. We’re doing just that in several areas. With a focus on selection within our breeding program, a multi-million dollar and several-decade investment in building a better prune tree and higher quality fruit is coming to fruition. The expectation is that the program not only allows for continued quality dominance for California Prunes in the global marketplace but also opens the potential for diversification for handlers as well as productivity and cost savings for growers. In another area – mechanical pruning – we’re bringing together researchers and funding from multiple institutions (CSU and UC) to help us understand the challenges and opportunities associated with cost savings in one of our most important but highest cost orchard tasks.

3. What is your favorite way to eat prunes?

Prunes are so versatile, so it is hard to choose. But as a lifelong ice cream enthusiast, I’ve been classing up this guilty pleasure lately by thinly slicing a few prunes, mixing them into a scoop of vanilla bean and topping that off with a splash of California olive oil. These additions add depth and texture to the experience, slowing me down when I’m (let’s be honest, usually unsuccessfully) trying not to eat the whole pint.

You can catch Zach at the UC Davis Prune Breeding summer 2023 Field Meeting coming up on August 15th at the Wolfskill Experimental Field Station in Winters. This will be a must-attend event for growers, handlers, and other industry stakeholders as we showcase the new promising cultivars and selections coming out of this program. Engagement in this process will be crucial for all as we make and commit to varietal selections in the coming years.