Ash decline (or “ash dieback” or “ash yellows”) is the most serious problem affecting white ash. The decline is especially prevalent in New York, Pennsylvania and Vermont but occurs from the Great Plains to the Atlantic coast at 39–45 N latitude. Mycoplasma-like organisms (MLO, the cause of ash yellows) have been found associated with most of the dying trees.Not all dying trees are infected and ash decline is thought to result from multiple causes – MLO plus various fungi and viruses, as well as atmospheric pollution and drought. Maintenance of good tree vigor is the primary control recommendation.
White ash is sensitive to ozone, sulfur dioxide, nitrous oxides, and associated acid deposition, which may cause the appearance of necrotic lesions on the leaves. Most of recent ash decline has occurred in areas with high levels of these gases.
No one has provided updates yet.