Growing the Valley

Latest Episodes:

Impact of sheep grazing on nut mummies in orchards Oct 15, 2026

Show notes

Winter sanitation is the foundation of navel orangeworm control, however orchard access can be difficult, particularly in wet winters. Houston Wilson, entomology specialist at UC Riverside, is part of a multidisciplinary team looking at sheep grazing in orchards. He has been looking at whether sheep eat mummy nuts, and how well they do it.

Episode transcript

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 owner, and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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

Alejandro Hernandez on phytophthora in pistachios Sep 17, 2026

Show notes

Phytophthora infections have become more common in pistachio. Alejandro Hernandez covers the biology of this disease, as well as his research on rootstock susceptibility and the efficacy of new fungicides. Please note that some of these fungicides are not registered for use in pistachio.

Episode transcript

Mention of a pesticide does not constitute a pesticide recommendation, and mention of specific trade names does not constitute an endorsement. Always follow the pesticide label. Find out more at ipm.ucanr.edu

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

ACC research in olives with Becky Wheeler-Dykes May 13, 2026

Show notes

Fruit removal is a serious issue in table olive production, namely because the fruit are harvested before they are ripe. ACC, an ethylene precursor, has the potential to improve fruit removal (please note that the commercial product is not registered in olives yet and cannot legally be used).

Becky Wheeler-Dykes, an advisor in Glenn, Colusa, and Tehama Counties, has been examining its efficacy in olives with a team of researchers at UC Davis. She shares some preliminary, and promising results in this week’s episode.

Episode transcript

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

Distribution uniformity return on investment tool May 06, 2026

Show notes

Anyone who has an irrigation system knows that it needs to be maintained for peak performance. Anyone who has an irrigation system also knows that almost everything seems to be more important in the moment than flushing those lines or checking pressures. A distribution uniformity test is a good way to assess the health of your irrigation system, but it isn’t always easy to figure out if the cost of making these fixes, particularly big fixes, will pencil out.

CURES got a grant a few years back to develop a tool to estimate the return on investment for making fixes to a system. Inge Bisconer and Parry Klassen share how the tool works and what spurred them to develop it in this week’s episode.

Episode transcript

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 owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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

Come to an upcoming extension meeting!

Sacramento Valley

The Nickels Field Day is on Tuesday May 19

San Joaquin Valley (scroll to the bottom)

2026 Prune Fruit Set, GDH30, and Cost of Thinning Apr 29, 2026

Show notes

In 2026 the Sacramento Valley prune industry is experiencing high fruit sets, high GDH 30, and a high cost of fruit thinning because of very diesel prices. Jaime Ott (UCCE Tehama), Domena Agyeman (UCCE Butte), and Franz Niederholzer (UCCE Colusa) break down prune grower crop management considerations given this tricky set of circumstances.

Upcoming Orchard Meetings:

The Almond Board of California also has four upcoming IPM meeting, tackling rodents, red leaf blotch, Carpophilus and other pests:

Bakersfield: Thursday, April 30

Wednesday, June 16, if you’re an almond variety nerd like me you can’t miss the Almond Board’s Crackout Event at Merced College

In the Sacramento Valley:

Nickels Field Day is Tuesday, May 19 in Arbuckle

I have two almond variety meetings at the Chico State Farm in June. Thursday June 11 and Thursday, June 25th.

The Third Thursday on July 16 will be in Yuba City and cover Walnut Mold

The Third Thursday on August 20 will be in Orland and tackle labor economics

Following a harvest season hiatus, there will be a Third Thursday on November 19 in Yuba City recapping 2026’s IPM challenges and lessons

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 owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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 information presented here is for general information purposes only. The "University of California" name and all forms and abbreviations are the property of its owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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

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Last update from the 3rd generation Regional Almond Variety Trial Apr 22, 2026

Show notes

The 3rd Generation RAVT recently wrapped up, and Luke, Phoebe, and Roger sit down one final time to discuss the findings. While the overall results are discussed, they also discuss each of the strengths and weaknesses of the 13 remaining varieties. It’s a long episode, check out the transcript if you are interested in something specific to get the timestamp.

Episode transcript

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 owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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

Come to an upcoming extension meeting!

Sacramento Valley

The Nickels Field Day is on Tuesday May 19

San Joaquin Valley (scroll to the bottom)

The effect of pollen on pistachio fruit and polyphenol deposition Apr 15, 2026

Show notes

Giulia Marino and Pat J Brown (both UC Davis) have been examining another potential influence on polyphenol deposition in pistachio: whether the pollen source impacts deposition rates. In this episode, Giulia shares her results, as well as some other unexpected findings from pistachio xenia (the effect of the pollen source on the fruit).

Episode transcript

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 information presented here is for general information purposes only. The "University of California" name and all forms and abbreviations are the property of its owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

2026: Earlier Almond Irrigation Start Revisited Apr 08, 2026

Show notes

Dr. Or Sperling (ARO-Volcani) and Zac Ellis (OFI) discuss the exciting 2025 results from their proactive irrigation scheduling application in California almond orchards.

You can ask questions and provide feedback to the researchers at:

Or Sperling: orsp@agri.gov.il or +972 52 6278189

Zac Ellis: Zac.ellis@ofi.com (559) 303-0599

Maciej Zwieniecki: mzwienie@ucdavis.edu

Come to an upcoming extension meeting!

In the San Joaquin Valley:

UC Cooperative extension has a Regenerative Almond Orchard Field Day on Tuesday, April 21st at the UC Merced Experimental smart farm

The Almond Board of California also has four upcoming IPM meetings, tackling rodents, red leaf blotch, Carpophilus and other pests:

Ceres: Wednesday April 22

Durham: Thursday April 23

Fresno: Tuesday April 28

And Bakersfield: Thursday, April 30

And finally Wednesday, June 16, if you’re an almond variety nerd like me you can’t miss the Almond Board’s Crackout Event at Merced College

In the Sacramento Valley we have a Third Thursday: Nematode Management in Orchards meeting in Orland on April 16 from 11-1

Nickels Field Day is Tuesday, May 19 in Arbuckle

I have two almond variety meetings at the Chico State Farm in June. Thursday June 11 and Thursday, June 25th.

The Third Thursday on July 16 will be in Yuba City and cover Walnut Mold

The Third Thursday on August 20 will be in Orland and tackle labor economics

Following a harvest season hiatus, there will be a Third Thursday on November 19 in Yuba City recapping 2026’s IPM challenges and lessons

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 owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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 information presented here is for general information purposes only. The "University of California" name and all forms and abbreviations are the property of its owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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

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Encore: Earlier Irrigation Start in Almond Apr 06, 2026

Show notes

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.

Have feedback or questions for the researchers?

Or Sperling: orsp@agri.gov.il or +972 52 6278189

Maciej Zwieniecki: mailto:mzwienie@ucdavis.edu

Zac Ellis (Olam): Zac.ellis@ofi.com (559) 303-0599

Come to an upcoming extension meeting!

In the San Joaquin Valley: Tomorrow Tuesday April 7 there is an Almond Board of California listening session in Modesto on Cornucopia Way at 8:30 AM

UC Cooperative extension has a Regenerative Almond Orchard Field Day on Tuesday, April 21st at the UC Merced Experimental smart farm

The Almond Board of California also has four upcoming IPM meetings, tackling rodents, red leaf blotch, Carpohilus and other pests:

Ceres: Wednesday April 22

Durham: Thursday April 23

Fresno: Tuesday April 28

And Bakersfield: Thursday, April 30

And finally Wednesday, June 16, if you’re an almond variety nerd like me you can’t miss the Almond Board’s Crackout Event at Merced College

In the Sacramento Valley we have a Third Thursday: Nematode Management in Orchards meeting in Orland on April 16 from 11-1

Nickels Field Day is Tuesday, May 19 in Arbuckle

I have two almond variety meetings at the Chico State Farm in June. Thursday June 11 and Thursday, June 25th.

The Third Thursday on July 16 will be in Yuba City and cover Walnut Mold

The Third Thursday on August 20 will be in Orland and tackle labor economics

Following a harvest season hiatus, there will be a Third Thursday on November 19 in Yuba City recapping 2026’s IPM challenges and lessons

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 owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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 information presented here is for general information purposes only. The "University of California" name and all forms and abbreviations are the property of its owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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

‍ ‍

Polyphenol deposition in pistachios - what is it, and how do cultivar and irrigation influence it? Apr 01, 2026

Show notes

Polyphenol deposition in pistachio kernels, also known as internal kernel discoloration, is a harmless phenotype of pistachios, where dark coloration appears on the internal surface of the pistachio cotyledons (the two halves of the kernel). It started showing up widely in the late 2010s/early 2020s, and researchers Georgia Drakakaki, Phoebe Gordon, and Minmin Wang have been investigating it from different angles (Phoebe from the field perspective; Georgia and Minmin from the anatomical and physiochemical perspective). In this episode, they share some initial results. We still don’t know what truly causes it, but we have some answers to basic questions.

Episode transcript

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 owner and its use does not imply endorsement of or opposition to any specific organization, product, or service.

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

Come to an upcoming extension meeting!

Sacramento Valley

And the Nickels Field Day is on Tuesday May 19

San Joaquin Valley (scroll to the bottom)