"Phytophthora ramorum Threatens California Nursery Industry" A recent find of Phytophthora ramorum in a Southern California Nursery has shut many doors to California product during the industry's busiest shipping season. To find out more about the recent developments and the association's efforts, click here. To get information on state restrictions, find the host list and read more about Phytophthora ramorum, go to the CDFA website at www.cdfa.ca.gov.