Phytophthora pathogens cause root and crown rots in many ornamental species and are a recurrent challenge in nursery production. These pathogens greatly affect plant health, resulting in devastating losses to the nursery industry, and have the associated risk of releasing pathogens of regulatory concern into trade and natural ecosystems. Efforts to control pathogen spread are costly, and as such, developing reliable and fast diagnostic tools to prevent and monitor pathogen introduction into nursery production is key. 

Environmental Horticulture & Controlled Environment Agriculture Advisor
Santa Cruz, Monterey, San Mateo, & San Benito Counties
[email protected]
(831) 228-9393

Environmental Horticulture Advisor
Riverside & San Bernardino Counties
2980  Washington St.
Riverside, CA 92504
[email protected]
206-321-9216

We are all feeling the pressure of summer heat, and so are our irrigation pipes! Fortunately, the pipes aren’t cracking (reminder to check your pressure regulators), and neither are California’s nursery growers. A recent hands-on irrigation training designed to help nursery growers improve water use efficiency and system performance was led by UC Cooperative Extension Advisors. The training provided both foundational knowledge and practical demonstrations tailored for container nursery systems.

University of California Cooperative Extension Advisors trained 107 nursery professionals during nine technical irrigation trainings at California nurseries in 2025. Trainings were conducted in either Spanish, English, or both languages, to accommodate the diverse workforce of the nursery industry. In the trainings, we covered the basics of plant physiology, soilless substrate science, and irrigation best management practices to improve water-use efficiency and plant health.

Phytophthora diseases are a growing concern to restoration and nursery plant production that have led to huge economic and ecological losses. Here in California, most people may know of Phytophthora (lit. “plant destroyer”) from the devastating outbreak of Sudden Oak Death, caused by the aerial Phytophthora ramorum, in the 1990s – 2000s in Northern California and Southern Oregon.