About Us

We are a team of University of California Cooperative Extension pomology farm advisors and research associates in the Sacramento Valley.

Katherine Jarvis-Shean is the Area Orchard Systems Advisor for Sacramento, Solano and Yolo Counties. She covers production research, education and assistance with almonds, prunes and walnuts, and can also field questions on citrus, pistachios, olives and stone fruit. Kat’s research projects include experiments on almond, prune and walnut rootstocks, fertilizer management, and the effects of warmer temperatures on bloom and harvest timing. Kat enjoys hiking in the Sierras with her dog and cooking big Italian dinners for friends and family. To sign up for Katherine’s newsletter for Sacramento, Solano, and Yolo counties, fill out this survey. Follow Katherine on Twitter: @AdvisorKat


Curt Pierce is the Irrigation and Water Resources Advisor for Glenn, Tehama, Colusa, and Shasta Counties. He covers a wide range of water-related topics but specializes in precision irrigation strategies for tree crops, such as almond, walnut, prune, olive, and pecan. His current research focuses on tree root architectures and their relation to plant/water relations. He is also spearheading the development of a UC Master Irrigator Program. In his free time, Curt enjoys riding whichever one of his motorcycles is currently running and spending as much time with his family as he can.


Franz Niederholzer

Franz Niederholzer is the UCCE Orchard Systems Advisor in Colusa and Sutter/Yuba Counties.  He is also the Research Coordinator at the Nickels Soil Lab in Arbuckle.  His primary crop responsibilities are almond and prune, with additional support for olive, cherry, plum, pomegranate, apple, citrus and pistachio (Colusa) production.  Current research topics in almonds and prunes include variety and rootstock trials, fertility management, and safe and effective spray application. Use this link to sign up for Franz’s newsletters. Follow Franz on Twitter: @Hwy20Orchardoc


Luke Milliron is the Orchard System Advisor for Butte, Glenn, and Tehama Counties. He is the primary contact for orchard questions in Butte County. His primary crop responsibilities include walnuts, almonds, and prunes. Research interests include new varieties, rootstocks and plant-based irrigation management. He is also co-host of the Growing the Valley Podcast which features practical UCCE updates on orchard production research in the Central Valley. Luke most enjoys being a dad, serving in Rotary, and playing pickleball. He is best reached by call or text at (530) 828-9666.


Clarissa Reyes is the Orchard Systems Advisor for Sutter-Yuba, Butte, and Placer Counties, based out of the UCCE office in Yuba City. Her primary crop responsibilities are walnut, peach, and kiwifruit, but she also has experience working with almond, prune, olive, and pistachio. Her research projects include variety and rootstock selection and drought-adapted management practices. She enjoys river floating, road trips, and rambunctious dinner parties.




Sudan Gyawaly is the Area Integrated Pest Management Advisor for Butte, Sutter-Yuba, Glenn, Colusa, and Tehama Counties. His primary crop responsibilities include almonds, walnuts, prunes, and peaches. Research interests involve sustainable pest management of key crops in the region. Sudan enjoys reading and traveling. Follow Sudan on Twitter: @AdvisorIPM.



Becky Wheeler-Dykes is the Orchard Systems Advisor serving Glenn, Tehama and Colusa Counties. She is based in Orland at the Glenn UCCE Office. As an Orchard Crops and Weed Ecology Advisor, she’ll be covering olives, prunes, walnuts and almonds as well as emphasizing weed management research in these cropping systems. She grew up on a small prune and walnut farm in Gridley and is happy to be settling down near family. After completing her undergraduate degree in Crop Science and Business Management at UC Davis, she earned her Masters in Entomology, where she focused on IPM in orchards. She can be reached by email at bawheeler@ucanr.edu or telephone at 530-884-9313.


Jaime Ott is a UCCE Orchard Systems Advisor for Tehama, Shasta, Glenn, and Butte Counties. Her primary crop responsibilities are walnut, prune, almond, and olive, but she is happy to try and field questions about anything with chlorophyll. She is finishing up her PhD from the UC Davis Department of Plant Pathology, where she has done work assessing walnut and almond rootstocks for resistance to crown rot caused by Phytophthora. She has also been involved in testing whole orchard recycling in almonds and optimizing anaerobic soil disinfestation (ASD) as an alternative to fumigation when replanting almond orchards. Jaime enjoys sharing the bounty of her garden with friends and neighbors and savoring the quiet of the mountains while backpacking with her husband.


Domena Agyeman is the Agriculture and Natural Resources Economics Advisor for Butte, Glenn, and Tehama Counties. He is responsible for ensuring economic viability in agricultural production, forestry, and other natural resources-based businesses. His responsibilities extend to promoting broadband accessibility and facilitating the effective utilization of online resources. Domena’s research interests encompass natural resources and environmental policy impact assessments, economic contributions and impacts analyses, producer decision-making assessments, and consumer preferences assessments. During his leisure time, Domena delights in watching soccer and reading about the beautiful sport. He can be reached by email at dagyeman@ucanr.edu


Adela Contreras joined UC ANR in 2022 as a Staff Research Associate and serves the Sacramento Valley with Katherine Jarvis-Shean and Franz Niederholzer across six counties. Among other research projects, she works on prune and walnut rootstock experiments and safe and effective spray application strategies. Adela is a first-generation college student from Salinas, CA, graduating with a B.S. in Environmental Science and Management at UC Davis in 2020.  She enjoys learning about soil, stand-up paddle boarding, kayaking, hiking, visiting family, eating, and adventuring with her dog Oakley.



Janine Hasey is the Tree Crops Farm Advisor Emeritus in Sutter, Yuba, and Colusa counties retiring after 38 years on July 1, 2019. Her focus is on walnuts, cling peaches, and kiwifruit. She served as the Extension County Director in Sutter and Yuba counties from 2014 until her retirement. In 1984, she started the UC Master Gardener program for Sutter and Yuba counties. In retirement, Janine will continue walnut research projects including no pruning/no heading training systems and managing several statewide rootstock trials. Janine is looking forward to more travelling and enjoys hiking, swimming and snorkeling.


Joe Connell, Farm Advisor Emeritus, served in Butte County for 34 years. His specialty is almonds, olives, citrus and ornamental landscape plants. Work with almond growers included research on pest and disease management, pruning, frost protection, irrigation, new rootstocks and varieties, and timely harvest. Joe was instrumental in establishing the Butte County Master Gardener program and hosted the first Honeybee Tech Transfer Team – part of a nationwide effort to help beekeepers strengthen honeybee colonies for pollination of almonds. He served as Butte County Extension Director from 2011 until his retirement in 2014. In retirement, Joe enjoys ongoing field work, travelling, and spending more time with family and grandchildren.


Former contributors:


Richard P. Buchner is the Orchard Crops Farm Advisor Emeritus for Tehama county in Red Bluff. He focuses on walnuts, almonds, and prunes in Tehama, Glenn, and Butte counties. Richard answers questions from California and walnut production regions throughout the world. His experience includes as M.S. degree from UC Davis in 1982 and 35 years as an orchard advisor before his retirement in 2017. His current research activity includes integrated pest management and rootstock evaluations for walnut and prune. In his spare time, Richard enjoys farming red wine grapes and crafting them into wine.



Allan Fulton was a UC Farm Advisor Emeritus and served in Tehama, Glenn, Colusa, Shasta, and Kings Counties for 32 years.  He worked in both orchard and field crops focusing on water management tools and practices to achieve consistent and competitive production and efficient use of water and nutrients.  He also worked to support local efforts to achieve sustainable groundwater management.  In retirement, Allan is helping new UC irrigation scientists establish their field research programs while wrapping up a couple unfinished projects of his own.  He hopes to have more time to spend with family and opportunity to travel.


Emily Symmes was the Area Integrated Pest Management (IPM) Advisor in Butte, Colusa, Glenn, Tehama, and Yuba-Sutter counties and Co-Associate Director of Agriculture for the UC Statewide IPM Program (ipm.ucanr.edu). Her position with the University was focused on all aspects of pest management in the wide variety of crops grown throughout the Sacramento Valley. Her research projects in almonds and walnuts include mating disruption, improvements to monitoring and treatment thresholds, and phenology models for key pests. You can follow Emily on twitter @SacValleyIPM.


Mariano Galla formerly was an Area Agronomy and Weed Science Advisor for Glenn, Butte and Tehama Counties. His interests include herbicide resistant weed management, herbicide drift and integrated pest management.



Dani Lightle, Orchards Advisor, UC Cooperative ExtensionDani Lightle formerly was the Orchard Systems Advisor in Glenn, Butte and Tehama counties. Dani’s research projects included almond and walnut horticulture, cover crops, and walnut rootstock evaluation.


Evie Smith was a Staff Research Associate in the southern Sacramento Valley supporting the research and extension programs of Katherine Jarvis-Shean and Franz Niederholzer. Her work focused on rootstock selection, strategic water use, pest control, and management adaptation strategies for changing conditions in almond, pistachio, prune, and walnut orchards.