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 sojae
"Phytophthora" root and stem rot of soybean was first observed in the United States in Indiana in 1948 and its causal agent, "Phytophthora sojae", first identified in 1958. In the 1970s, soybean plants only had one single-resistance gene, meaning they were more susceptible to an infection. Eventually plants with this gene were killed by new races of "Phytophthora sojae". As a result, several states suffered significant yield losses particularly in the state of Ohio, which lost 300,000 acres of soybean plants in a year. Soon thereafter, a variety of new disease prevention methods were implemented and as a result this disease is currently one of the well-managed and well-known soybean diseases in the USA.