Wood Decay Fungi

Hosts, Symptoms & Signs

• all trees and shrubs
• wood decay fungi may form fruiting structures called conks on affected branches and trunks, but not always
• presence or absence of conks is not an indication of wood decay
• wood decay fungi can degrade wood strength leading to stem or branch failure

White Rot

• caused by fungi that decompose most of the wood components
• the leftover material is very light

Brown Rot

• fungi causing a brown rot cannot decompose lignin, giving it a reddish-brown color
• limbs can die back, but in some cases wood decay fungi can hollow out branches and tree trunks and the tree will show no symptoms; these trees are prone to sudden breakage in storms

Disease Cycle

• spores of wood decay fungi enter through wounds caused by winter injury, lawn mowers, incorrect pruning or insect feeding, and start colonizing and decomposing the wood; this process can go unnoticed for years

IPM Recommendations

• Remove affected branches. If the trunk is affected, remove the tree.
• If unsure about the presence of wood decay, have a certified arborist evalutate the tree.