Courtesy of Tracey Olson, PDA. Controlling Phytophthora Root Rot. HortScience 28:1106-1108. A tree demonstrating phytophthora symptoms can sometimes be saved by removing the soil from around the base of the tree all the way down to the top of the main roots, cutting away any bark that’s oozy or dark and leaving the root system exposed. Fungi thrive under wet conditions; Phytophthora rarely becomes an issue in soil that drains well. 7 Maloney, K.E., Wilcox, W.F., and Sanford, J.C. 1993. Plant Disease Reporter 61:1045-1048. Phytophthora root rot is a serious fungal infection that attacks many types of vegetation. Root rot-causing Phytophthora species can survive in the soil for years, as long as moist conditions persist. Phytophthora root rot. Low-lying areas with poor water drainage are especially prone to root rot diseases such as Phytophthora (Figure 2). Raised beds and metalaxyl for controlling Phytophthora root rot of raspberry. Life Cycle. Disease symptoms are distinguishable from Armillaria root rot because mycelial mats do not develop in tissues infected with Phytophthora root rot. Field symptoms of Phytophthora root rot are first noticed when new primocanes (first-year canes) wilt and the shoot tips die back. Leaves turn yellow or scorch from the margins. Figure 2. It can spread through splashing rain, irrigation water, and runoff water. The phytophthora rots are especially troublesome in gardens that have heavy soil and a climate with abundant rain. According to plant pathologists at Auburn University, prevention is the best way to … Roots decay and trunk base may discolor from Phytophthora infection. Sometimes, the cause of root rot is not as simple as waterlogged soil. Figure 1. Symptoms and Signs. Floricanes (second-year canes) of affected plants have weak lateral shoots. The direct cause may be a fungus, such as Phytophthora. Shrubberies, woody ornamental species and some fruit-bearing cultivars are its most common hosts. But, just as poor drainage enables excessive water to become a problem, so waterlogged soil is an enabler for Phytophthora. Root rot is an infection caused by fungal pathogens, such as Annosum and Armillaria, or molds, such as Phytophthora or Pythium. Phytophthora root rot infects the smaller fine roots, resulting in necrotic tissue and eventually, if the disease goes untreated, causing the death of the plant. Signs and Symptoms of Root Rot in Pine Trees. There are a number of different Phytophthora species, all causing very similar symptoms. Phytophthora cinnamomi causing root rot and wilt of nursery-grown native western azalea and salal. After honey fungus, Phytophthora root rot is the most common cause of root and stem base decay of a wide range of trees and shrubs. Examine roots for symptoms of decay and absence of an extensive feeder root system (Figure 1).