In this Summer 2025 issue of the UCNFA Newsletter, our Featured Articles focus of diseases of nursery crops, presenting the most recent diagnostics data from ornamental nurseries in California out of the Greenhouse and Nursery Pathology Lab at UC Davis. We will also discuss the impact and biology of powdery mildew in California nurseries, including practical guidelines for identification and management. In the Science to the Grower section, we take a deep dive into soilborne Phytophthora crown and root rot diseases in commercial nurseries, and disease management strategies. With a theoretical understanding established, we then offer practical guidance for scouting various plant diseases in the nursery. Additionally, we introduce a biological water filtration technology to remove plant pathogens from irrigation water. Next up in Get Cultured, we continue with part three of our Soil and Water pH series on the effect of fertilizer on water pH, then provide a brief overview of how to recognize signs of irrigation patters that may contribute to the spread of waterborne diseases through the nursery.  In our last two sections, Regional Advisor Reports and Campus News and Research Updates, we highlight a nonprofit seed farm in the Santa Monica Mountains producing California native seeds for restoration, then offer grower perspectives on a proposed urban tree certification program. Lastly, we end with an update on two irrigation trainings offered by UC Cooperative Extension and introduce the Accreditation to Improve Restoration (AIR) program, assisting nurseries across the state to produce high quality Phytophthora-free restoration plants and protecting California's sensitive native habitats.  

• I. Featured Articles: Diseases of Nursery Crops
• What We See in the Lab: Disease Diagnostics in Ornamentals in 2024
  
  Understanding Powdery Mildew in Nurseries and Floriculture
• II. Science to the Grower
• Root of the Problem: Phytophthora in Ornamentals
  
  How to Scout for Plant Diseases in the Nursery
  
  Slow Sand Filters: A Biological Treatment Technology to Remove Plant Pathogens from Irrigation Water
• III. Get Cultured: Horticultural Methods, Techniques, Growing Practices, & Principles
• Soil and Water pH, Part 3: How Do Fertilizers Affect pH?
  
  Recognizing Water-Related Disease Issues in Container Nurseries
• IV. Regional Advisor Reports
• Santa Monica Mountains Native Seed Farm
  
  Perspectives from the California Nursery Industry on State-Specific Tree Quality Standards or Certification
• V. Campus News and Research Updates
• Pipe Dreams and Pressure Gauges: An Irrigation Training from UC Cooperative Extension
  
  Technical Irrigation Trainings in California
  
  Accreditation to Improve Restoration: A Program for the Production of Phytophthora-free Restoration Plants
  
  California Nursery Conference 2025 Announcement

Contributing Authors: Jessie Godfrey, Grant Johnson, Don Merhaut, Johanna Del Castillo Múnera, Ana Pastrana, Bruno J.L. Pitton, Chris Shogren, Gerry Spinelli, Emma Volk, Dean Watson

Prepared for publication by: Dean Watson