Phytophthora ramorum
Detection of "P. ramorum" in watercourses has emerged as the earliest of early detection methods. This technique employs pear or rhododendron baits suspended in the watercourse using ropes, buckets, mesh bags, or other similar devices. If plants in the watershed are infected with "P. ramorum", zoospores of the pathogen (as well as other "Phytophthora" spp.) are likely present in adjacent waterways. Under conducive weather conditions, the zoospores are attracted to the baits and infect them, causing lesions that can be isolated to culture the pathogen or analyzed via PCR assay. This method has detected "P. ramorum" at scales ranging from small, intermittent seasonal drainages to the Garcia, Chetco, and South Fork Eel Rivers in California and Oregon (144, 352, and 689 mi2 drainage areas, respectively). It can detect the existence of infected plants in watersheds before any mortality from the infections becomes evident. Of course, it cannot detect the exact locations of those infected plants: at the first sign of "P. ramorum" propagules in the stream, crews must scour the watershed using all available means to find symptomatic vegetation.
Curry County, Oregon
In 2001, the native tanoak in the county were afflicted by sudden oak death, caused by infection of "Phytophthora ramorum". The pathogen, which by 2016 had killed hundreds of thousands of tanoaks in the county, thrives in moist places along the coast. It has killed other kinds of oaks such as California black oak in a region that includes many California counties as well as Curry County, and it has infected and damaged a variety of conifers and shrubs such as camellia. In Curry County, it threatens timber production, plant nurseries, and Christmas tree farms.