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...

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. Come to an upcoming extension meeting! 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...

Luke Milliron, Phoebe Gordon, and Roger Duncan discuss the three almond variety trials 10 years after they were planted across the Central Valley.

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. Come to an upcoming extension meeting! Sacramento Valley San...

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...

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...

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...

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...

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.

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! Come to an upcoming extension meeting! Sacramento Valley San Joaquin Valley (scroll to the bottom) Mention of an agrichemical does not...

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...

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...

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. Come to an upcoming extension meeting! Sacramento Valley San Joaquin Valley (scroll to the bottom) Mention of an agrichemical does not constitute a recommendation, merely the sharing of research findings....

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

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. Come to an upcoming extension...

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...

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. Come to an upcoming extension meeting! Sacramento Valley San Joaquin Valley (scroll to the bottom) Mention of an agrichemical does not...

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.

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. Come to an...

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. Come to an upcoming extension meeting! Sacramento Valley San Joaquin Valley (scroll to the bottom) Mention of an agrichemical does not constitute a recommendation, merely the sharing...

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. Come to an upcoming extension meeting! 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...

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

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! Come to an upcoming extension meeting! 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...

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...