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.
Phytophthora kernoviae
Phytophthora kernoviae is a plant pathogen that mainly infects European beech ("Fagus sylvatica") and "Rhododendron ponticum". It was first identified in 2003 in Cornwall, UK when scientists were surveying for the presence of "Phytophthora ramorum". This made it the third new "Phytophthora" species to be found in the UK in a decade. It was named "Phytophthora kernoviae", after the ancient name for Cornwall, Kernow. It causes large stem lesions on beech and necrosis of stems and leaves of "Rhododendron ponticum". It is self-fertile. It has also been isolated from "Quercus robur" and "Liriodendron tulipifera". The original paper describing the species, stated it can infect "Magnolia" and "Camellia" species, "Pieris formosa", "Gevuina avellana", "Michelia doltsopa" and "Quercus ilex". Since then many other plants have been identified as natural hosts of the pathogen. Molecular analysis has revealed that an infection on "Pinus radiata", recorded in New Zealand in 1950, was caused by "P. kernoviae".