Informational table showing disease name, symptoms, pathogen/cause, and management of Pieris diseases. Disease Symptoms Pathogen/Cause Management Phytophthora root rot Plants are stunted and then wilt, yellow, and die. Roots with few feeder roots die. Stem wood at the soil level has red-brown discoloration. No obvious fungal fruiting structures are formed. Phytophthora Purchase disease-free plants. Especially inspect southern-grown, containerized material before planting. Use clean, disinfested tools. Following a positive diagnosis, remove infected plants. Avoid overhead watering. Apply a fungicide to protect healthy plants.