Collar, foot, root, and crown rots—Phytophthora spp.
Several species of the Phytophthora fungi infect the roots or crowns of landscape plants. Plants
wilt and leaves become discolored, stunted, and drop prematurely. Often a vertical streak, stain, or canker
becomes visible on infected trunks. A cinnamon brown or dark gray discoloration may be seen beneath the
bark. Black or reddish sap may ooze from darkened areas of infected bark. Infected mature plants grow
slowly and may gradually decline. Twigs and branches die back and the entire plant can be killed.
Identification | Life
Prepare the site well before planting and provide proper
irrigation. In soils that are
compacted, drain poorly, or are usually damp, and where Phytophthora root rot is a problem, improve
drainage and plant only species believed to be resistant.
For more information, see the Phytophthora
Root and Crown Rot Pest Note.
Branch dieback on plant with root rot
Bark cut away reveals dark discoloration