Hypoxylon occurs on aspen, alder, birch, maple, oak, and willow. Although some authorities separate the different forms of the fungus into three species, we combine all the forms into one species. Hypoxylon pruinatum. The disease ranges across southern Canada and northern United States and most probably throughout the range of the aspen. It is easily spotted in more advanced stages because the trees are girdled, killed, and broken at the position of the canker (Fig. 27-1). Small, yellow leaves are borne on seriously affected trees and they persist until spring if the tree is killed during the summer. Dead branches bearing persistent leaves are called flags.
KeywordsYellow Leaf Spore Wall Dead Branch Bark Tissue Ascospore Discharge
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- Bier, J. E., Hypoxylon Canker of Popular, Studies in Forest Pathology. III. Tech. Bul. 27 (Publ. 691) Dom. Can. Dept. Agric, 1940.Google Scholar