Saturday, October 15, 2016

Phytophthora Root and Crown Rot Update

From the California Oak Mortality Task Force Report September 2016:  "First detection of Phytophthora quercina in the US, associated with outplanted Quercus lobata, valley oak – P. quercina was recently isolated from valley oaks (Quercus lobata) as part of an evaluation conducted by the Rizzo Lab (UC Davis) and Phytosphere Research on restoration sites managed by the Santa Clara Valley Water District...  It has been rated the # 1 Phytophthora species of concern for introduction into the US in a USDA Plant Epidemiology and Risk Analysis Laboratory (PERAL) report. P. tentaculata, recently found in association with multiple native plant species in CA native plant nurseries, was rated as # 5 on the same list."