A well-watered plant that suddenly wilts or unexpectedly drops its leaves could be infected with the soil pathogen Phytophthora. The disease it causes, Phytophthora root and crown rot, can affect many plants, including ornamental trees and shrubs, fruit trees, and vegetables. Plants growing in water-logged or poorly draining soil are susceptible to Phytophthora infection, leading to aboveground symptoms like tip dieback, stem cankers, thinned canopies, and discolored foliage, or plant death.
To help you identify and manage this disease, UC IPM has recently updated the Pest Notes: Phytophthora Root and Crown Rot fact sheet. Authored by UCCE advisors Jim Downer, Steven Swain, and Ed Perry, this revised publication includes a new section on mulching to control tree diseases. New photographs showing symptoms in landscape plants to aid in identification have also been added.
Visit Pest Notes: Phytophthora Root and Crown Rot to learn how to distinguish Phytophthora root rot from other diseases, symptoms to look out for, and cultural controls for prevention. To help determine whether your plant may have this disease, a different disease, or another issue, check out the Plant Problem Diagnostic Tool.