Where has Phytophthora ramorum been found?
Natural areas found with infection have been along the northern and central coast of California, as well as one county in southwest Oregon. To date, all of the natural areas found with infection are cool, moist, and frequently foggy. Forests with disease are made up of a mixture of host and associated host plants, and often have either tanoak or California bay laurel trees present. In addition to natural infection in woodland and forested areas, Phytophthora ramorum has also been found in the nursery system on host and associated plants. It is because of these detections that the nursery industry is undergoing extensive surveying for the pathogen in high-risk areas as well as falling under heavy regulation. Nurseries in a naturally infested area, or that have been found with previous pathogen infestations, must have a compliance agreement in place before being allowed to ship host and associated plant material. Additionally, any California nursery that has host and associated plants an
