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 erythroseptica
A multi-faceted approach is recommended to control pink rot. Sanitation of fields to reduce the amount of residues and volunteer potatoes is important to remove sources of inoculum or places the pathogen can overwinter. A crop rotation of 3–4 years is recommended to limit the amount of surviving spores in the soil, which is the main form of inoculum. Most cultivars of potatoes currently in production are susceptible to pink rot; however, some are more resistant than others. Varieties that are particularly susceptible are Dark Red Norland, Red LaSoda, Russet Norkotah, and Snowden.