Growing the Valley

Dr. Roger Baldwin (UCCE Specialist in Human-Wildlife Conflict Resolution) discusses orchard management of pocket gophers, ground squirrels, voles (meadow mice), roof rats, and deer mice. This is a compilation of two episodes from 2022, with Luke Milliron providing a new introduction with highlights from 2024/2025.

Skip to the pest you’re concerned about:

00:05:35 Pocket Gophers

00:35:12 Ground Squirrels

00:48:33 Voles/Meadow Mice

01:02:38 Roof Rats

01:12:39 Deer Mice 

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In the Sacramento Valley:

Almond Variety Trials: 2025 Field Meeting is next Wednesday April 30

Drs. Or Sperling (ARO-Volcani) and Maciej Zwieniecki (UC Davis) discuss their groundbreaking research on almond irrigation. That research has culminated in an exciting irrigation scheduling application. We also get an overview of almond production in Israel. The UC Davis Carbohydrate Observatory is also referenced.

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Sacramento Valley

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The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is fo...

Cytospora is a devastating fungal canker disease in California prune production. Themis Michailides (UC Davis at Kearney Ag Center) updates us on the biology and management of this important disease. Themis has covered this disease on the podcast before but is back with key updates.

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The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is...

Fire is a fact of life in California, whether you live in a fire-prone area or you live in an area that can be impacted by smoke. Smoke doesn’t just cause health issues to animals - it impacts plants, too! Jessica Orozco and Maciej Zwieniecki at UC Davis have been using citizen science data from The Carbohydrate Observatory to try to guess at the impacts on tree nut orchards in the Central Valley.

Are you interested in contributing to the carbohydrate observatory? You can find out how to submit samples here, but don’t forget to shar...

English/Persian walnuts have a fairly high chill requirement and can suffer from poor bud break and reduced yields in years with marginal or low chill accumulation. Katherine Jarvis-Shean (UCCE Yolo, Solano, and Sacramento Counties) has been looking at the efficacy of rest-breaking agents, both in semi-controlled conditions and in commercial orchards. She shares how well they work, their effect on yields, budbreak, and walnut quality, and the surprising interaction of chill accumulation with rest-breaking efficacy. To find out more about Katherine’s research, you can read more here or listen to a previous episode here.

Come to...

Nonstructural carbohydrates are the energy storage compound of trees. They are built from simpler sugars that are created via photosynthesis, and the synthesis of starch from these sugars and the breakdown of starch back into simple sugars is a dynamic relationship that is involved in, or may even signal, the transition from dormancy into bloom. Guests Maciej Zwieniecki and Katherine Jarvis-Shean also discuss why dormancy breaking agents work, the tastiness of starch vs sugar, and more!

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...

Sam Sandovol Solis, professor of cooperative extension in water management at UC Davis, pulls out the crystal ball for the fourth time to predict what the 2024-2025 water season will end up looking like. Sam and podcast host Phoebe also discuss water management in a future with uncertain supplies, and what growers can do in the present to maximize soil water, and how to think about water availability in the long term.

Sam mentioned a map that shows groundwater recharge suitability, you can find it here.

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Sacramento...

Almonds and pistachios are native to arid climates and are drought tolerant tree species. In California however, the high cost of production and land value pushes growers to maximize yields, which means trying to meet the full evaporative demand (though many growers apply much less water than this!)

This is not the strategy everywhere, however, even in other areas that also have high production costs. In this episode, Phoebe discusses almond production in the Iberian Penninsula with Sebastian Saa, pistachio production in Sicily with Giulia Marino, and pistachio production in Iran and Afghanistan with Louise Ferguson.

At a time when California orchard farmers are being challenged by poor economics and tightening regulations – coming irrigation advances promise labor and time savings. I speak with Tom Devol (retired Almond Board of California) to discuss the past, present, and future of California orchard irrigation. 

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The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is fo...

Phellinus heart rot in prune trees destroys structural integrity. Laurel Hoffman (UC Davis) updates us on the biology and management of this important disease.

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The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is for general information purposes only. The "University of California" name and all forms and abbreviations are the property of its own...

We posted this episode back in 2020 and are pulling it out of the archives. It’s an interesting story of the surprising resilience of a tree after wildfire events that are unfortunately too common.

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The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is for general information purposes only. The "University of California" name and a...

Sudden autumn freeze events still sneak up on California walnut growers – as they did to some growers last Halloween (2023). Clarissa Reyes (UCCE Sutter-Yuba) and Luke Milliron (UCCE Butte) discuss the steps to prepare for freeze in walnut. At the time of posting – there was patchy frost on the morning of 11/18/24 and predicted also for 11/19/24. Thankfully, there is surface soil moisture in orchards from recent rains and the temperature decline to freezing temps has been gradually taking place over the last few weeks.

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Sacramento Valley

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It’s been a year since Carpophilus truncatus (Carpophilus beetle) was found in California. Jhalendra shares some research updates and observations with host Phoebe Gordon.

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Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. The label is law. Find out more at ipm.ucanr.edu.

The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opin...

Luke Milliron, Phoebe Gordon, and Roger Duncan discuss the three almond variety trials 10 years after they were planted across the Central Valley. Thanks to our grower cooperators and to the Almond Board of California for funding these trials.

You can find more about the results discussed in our 2023 report. Details discussed can also be found in an upcoming fall/winter issue of West Coast Nut.

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The views, thoughts, and opinions expressed are t...

Pistachios alternate bear, which changes the dynamics of nitrogen uptake and allocation within the tree on a year to year basis. To add to this, the newer cultivars, Golden Hills and Lost Hills, alternate bear less than Kerman, especially when they are planted on the high vigor UCBI. Doug Amaral (UCCE Kings County) decided it was time for an update on the nitrogen demand curves, and we discuss what he’s found in this episode.

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Sacramento Valley

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The vi...

A Third Thursday x Growing the Valley collab! Karla Caldera (CSUC graduate student) discusses the research she is conducting at the walnut variety trial located at the Chico State University Farm (2:27) and Dr. Pat J. Brown talks and answers grower questions about the Walnut Improvement Program at UC Davis that aims to bring improved plant material to the walnut industry (9:50).

Check SVO for future Third Thursdays: Things from the Field events, and a brief article on the walnut variety trial.

Thank you to the Almond, Pistachio, Prune, and Walnut Boards of California for t...

Trying to predict when trees will come out of dormancy and whether they’ve stayed in dormancy for a long enough period of time is a very old science. The methods for calculating chill has changed, but the measurement method, measuring air temperatures, has not. Giulia Marino, Professor of Cooperative Extension at UC Davis, measured the bark temperature of cherry trees in a recent research project. You can probably predict what she found, but how different the temperatures are will surprise you! Listen to find out more!

Are you interested in looking at Giulia’s work or cont...

Phoebe breaks down the importance and best practices surrounding potassium nutrition in orchard crops.

Phoebe and Franz Niederholzer wrote an excellent article on K nutrition

CDFA – FREP Fertilization Guidelines

Sign up for the 2024 Pistachio Short Course here:

Thank you to the Almond, Pistachio, Prune, and Walnut Boards of California for their kind donations. Thank you to Muriel Gordon for the music.

The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and info...

Measuring plant water status is a critical but underused tool in irrigation management. It allows us to determine whether plants actually need water, but is time consuming, done during the hottest portion of the day, and difficult to do at a large scale. Commercial devices to measure plant water status are a fairly recent addition to the agricultural tech field, but are they accurate? Isaya Kisekka, a professor of water management at UC Davis, has been evaluating them in almonds and shares what he’s found so far.

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Sacramento Va...

Jaime Ott discusses the resurgence of prune brownline in the northern Sacramento Valley. In addition to prune, Jaime reminds us to be on the lookout for symptoms of Tomato ringspot virus in almond, peach, and cherry.

Also caused by Tomato ringspot virus:

Learn about Yellow Bud Mosaic in almond and peaches

Learn about Cherry Stem Pitting  

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The views, thoughts, and opinions expressed are the speaker’s own and do n...

Houston Wilson, Professor of Cooperative Extension in entomology with UC Riverside, gives us our semi-yearly update on Sterile Insect Technique (SIT) work in Navel Orangeworm, through work completed in 2024. It’s a long (20 year or so) long road, but may provide an additional tool in the IPM toolbox for controlling navel orangeworm. Listen to find out more!

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Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. Th...

Incorporating large amounts of woody biomass into soil, such as in whole orchard recycling (WOR), can promote carbon sequestration, nutrient recycling, and ecosystem health in agricultural fields. Yet uncertainty regarding the effects of WOR on soil carbon and nitrogen dynamics influences management decisions. Recently, Mae Culumber, Ph.D. with UC Cooperative Extension, Suduan Gao, Ph.D. with the USDA Agricultural Research Service, and others performed research to evaluate the effects of woodchip size and interaction with nitrogen fertilization on carbon dioxide and nitrous oxide emissions as well as soil organic carbon change. On this episode of Growing the Valley...

Soil health is broad term that encompasses a important topic: functional soil that can support human activities, animals, and plants. Measuring soil health can be difficult even for soil scientists, but in today’s episode, Sarah Light shares some tools that growers, PCAs, and CCAs can use to judge soil health in their or their clients’ orchards.

Thank you to the Almond, Pistachio, Prune, and Walnut Boards of California for their kind donations. Thank you to Muriel Gordon for the music.

The views, thoughts, and opinions expressed are the speaker’s own and do not repres...

In 2023 UCANR advisors and specialists got an unusual number of farm calls on branch cankers in almonds, many of which turned out to be aerial phytophthora. Florent Trouillas with UC Davis goes over the pathogen, its lifecycle, and the conditions in 2023 that led to this outbreak.

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Sacramento Valley

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Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. The label is law. Find out more at ipm.ucanr.edu.<...

Luke Milliron discusses the growing list of problems with the Monterey almond variety in the northern Sacramento Valley.

Leafing failure (what is it)

Leafing failure (what might be causing it)

Flowering failure

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The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is for general information purposes only. The "Uni...

This week, we share an episode that was TWO YEARS IN THE MAKING (if you count continually rescheduling episode recording sessions due to various conflicts and then forgetting about it for a year as making an episode). Phoebe interviews Amisha Poret-Peterson with the USDA-ARS on the basics of soil microbiology. We discuss the complexity and role of the soil microbiome, bulk soil vs the rhizosphere, and more! Listen to hear some very amazing things.

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Mention of...

Lu Zhang provides an update on work published last year on the effect of dust on pistachio pollen, flowers, nut set, and blanking (it’s not good!). Please note that there are other physiological causes of blanking, such as incomplete pollination or aborted kernel development, and that we have not determined how much dust could contribute to blanking in the field. Also, the episode was recorded before the heavy rains in March in the southern San Joaquin Valley, so high dust conditions may not occur this year.

The American Society for Horticultural Science dropped its paywall, so yo...

Cover crops! They’re not just for almonds (despite the bulk of California orchard cover crop research being in that crop). Daniele Zaccaria has been conducting research on cover crops in California pistachio orchards and shares what he has found, including some interesting possibilities as to why they found higher yields in orchards with cover crops.

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Sacramento Valley

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Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. The la...

Luke Milliron and Ken Shackel (UC Davis) sit down to talk about the decade plus of research investigating when to start irrigation in the spring for walnut orchards.

If you want to learn more about incorporating the pressure chamber to improve orchard health and cut costs - contact your local farm advisor or Luke at (530) 828-9666

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The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, an...

In a world where it feels like we have a new invasive pest every month, sometimes it’s hard for an arthropod to stand out. Last year, the nut industries were put on notice by Carpophilus truncatus, a tiny beetle that has commandeered big attention. Lucky for us (and unluckily for the Australians), we aren’t alone in trying to figure out how to keep this beetle under control. Houston Wilson shares what we know about its spread in the state, and what we can learn from Down Under.

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Sacr...

Phoebe talks with Richard Heerema, the pecan specialist for New Mexico State University, about pecan botany and physiology, and why it may not be as good of a choice for areas prone to flooding as you think it might be. This is an episode for those who are thinking of planting pecans but have not done so.

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Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label...

Florent Trouillas, a professor of Cooperative Extension in plant pathology at UC Davis, describes how pistachios become infected with phytophthora and how to manage it. He also describes his research on this newly registered product.

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Sacramento Valley

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Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. The label is law. Find out more at ipm.ucanr.edu.

The views, thoughts, and opinions expressed are the speaker’s...

Sarah Castro (UC Davis) discusses how new prune varieties can improve a grower’s bottom line!

scastro @ ucdavis.edu

Insta: @cali.prunebreeder

Initial episode on the prune breeding program with Sarah

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Sacramento Valley

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The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is for general information purposes only. The "University of Ca...

Phoebe and Sam discuss the water outlook for 2024. Some things have changed since last year, but some things have stayed the same. Listen to the entire episode to hear a public service announcement about tequila and agave production in the state!

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Sacramento Valley

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Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. The label is law. Find out more at ipm.ucanr.edu.

The views, thoughts...

While we posted this episode all the way back in 2018, we thought we would dust it off since the information is still timely.

Phoebe interviews Craig Kallsen, the now emeritus subtropical and pistachio tree crop advisor for Kern County, to talk about what we know and don’t know about dormancy in pistachios. Craig also talks about a paper he published back in 2017, looking at the correlation between winter and spring temperatures and current season’s yield. This is an ongoing area for research and there are still more questions than we have answers.

This epis...

Brittney Goodrich provides an update on what almond growers can expect in the 2024 pollination season. You can find the economic calculator here.

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Sacramento Valley

San Joaquin Valley (scroll to the bottom)

Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. The label is law. Find out more at ipm.ucanr.edu.

The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the Un...

Navel Orangeworm (NOW) wreaked devastating impacts on the California almond industry in 2023. I sat down with Dr. Franz Niederholzer (UCCE Colusa) after harvest to discuss what had happened and what needs to be done to win the war against NOW in 2024.

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Sacramento Valley

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Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings. Always follow the label. The label is law. Find out more at ipm.ucanr.edu.

The views, thoughts...

Dr. Andreas Westphal provides an update on tightening regulations and the latest research progress for nematode management in walnuts and other orchard crops.

Dr. Westphal’s upcoming nematode management field days will be on Tuesday November 28 (walnut), and Wednesday November 29 (almond) at the Kearney Ag Center (9240 S. Riverbend Ave, Parlier, CA). Who is it for? Field research representatives, farm advisors, PCAs, growers, consultants (CEU other(O): 4.0 for each day). What will you learn about? Rootstock development, pre-plant soil treatments, and post-plant treatments. REGISTRATION for this event: https://surveys.ucanr.edu/survey.cfm?surveynumber=41461 Early registration is encouraged. Co...

Mel Machado (Blue Diamond Almond Growers) discusses important considerations for timing almond harvest, including grower objectives, varieties, and nut quality.

Resource links related to almond harvest:

When do you shake almonds?

Maintaining Quality with Pick Up & Stockpiling Best Practices

Thank you to the Almond, Pistachio, Prune, and Walnut Boards of California for their kind donations. Thank you to Muriel Gordon for the music.

The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The ma...

Pistachios are very salt tolerant, at least compared to most of the other orchard crops that are grown in California. However, this does not make them immune to the effects of salinity. Daniele Zaccaria recently wrapped up a four year study examining the water use of trees under varying levels of soil salinity and found that water use decreases as soil salinity increases. This has major implications for tree health and water use post SGMA. Listen to find out more.

The views, thoughts, and opinions expressed are the speaker’s own and do notrepresent the views, thoughts, an...