Powdery Mildew 7. It is equally important in both hardwoods and conifers. Heart rot is not limited to one area of a tree. It occurs both in upper and lower regions of trees, better classified as top rot and root and butt rot. Heart rot refers to the decay of the heartwood of a living tree.
Heart rot is caused by a variety of species of wood decay fungi.
It is impossible to determine the species of fungus responsible for heart rot of a specific tree without a reproductive body of the fungus. The heart rot of the crabapple pictured in Fig. 2 Common infection courts for wood decay fungi include broken branches, fire scars, and mechanical wounds from logging, pruning, and various machines. 3 note the decayed area where a limb was pruned. This is a very common site for wood decay fungi to enter.