Armillaria root disease.

Armillaria root disease is found throughout temperate and tropical regions of the world. In the continental United States, the disease has been reported in nearly every State. Hosts include hundreds of species of trees, shrubs, vines, and forbs growing in forests, along roadsides, and in cultivated areas. The disease is caused by fungi, which live as parasites on living host tissue or as saprophytes on dead woody material. The fungus most often identified as causing the disease is Armillaria mellea (Vahl: Fr.) Kummer. Recent research, however, indicates that several different but closely related species are involved. Therefore, the generic term Armillaria is used to refer to this group.