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 capsici
Although resistance has been developed in the cultivars Adra (Abbott and Cobb Seed Co.) and Emerald Isle (Harris Moran Seed Co.), they do not possess sufficient horticultural characteristics accepted by bell pepper growers in the U.S.. Paladin (Novartis Seed Co.) has excellent resistance to the crown rot phase of "Phytophthora" rot and is acceptable to most growers. Paladin does not possess resistance to the foliar phase of this disease and one must use copper fungicides along with the resistant strain for control.