Ecological Impact

Armillaria root disease occurs around the world in many places where woody plants grow. Depending on the environmental conditions, host plant, and host condition, different Armillaria species occur in different geographic regions, and each Armillaria species displays distinct ecological behaviors, ranging from a virulent primary pathogen, secondary pathogen, beneficial saprophyte, or beneficial mycorrhizal symbiont of orchids in Asia. Armillaria has some interesting, but disparate, features related to its ecological functions. For example, Armillaria is known for its bioluminescence, which is the subject of many hypotheses, but the ecological function of this property remains largely unverified. In eastern Asia, Armillaria spp. can form unique mycorrhizal relationships with achlorophyllous, mycoheterotrophic orchids, such as Galeola, Gastrodia, and Cyrtosia, which contain species that are important in traditional medicine. In other situations, Armillaria can participate in symbioses with other fungi, where it can serve as the host (e.g., Entoloma abortivum) or parasite (e.g., Wynnea).