Phytophthora ramorum
Trials of silvicultural methods for treating "P. ramorum" began in Humboldt County in northwest coastal California in 2006. The trials have taken place on a variety of infested properties both private and public and have generally focused on varying levels and kinds of host removal. The largest () and most replicated trials have involved removal of tanoak and bay laurel by chainsaw throughout the infested stand, both with and without subsequent underburning designed to eliminate small seedlings and infested leaf litter. Other treatments included host removal in a modified “shaded fuelbreak” design in which all bay laurel is removed, but not all tanoaks; bay and tanoak removal using herbicides; and removal of bay laurel alone. The results of these treatments are still being monitored, but repeated sampling has so far detected only very small amounts of "P. ramorum" in the soil or on vegetation in the treated sites.
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".