A Technical Report from The Bartlett Tree Research Laboratories 374
Ash yellows (AY) is a chronic, systemic disease that affects many North American ash species. White ash and green ash are the most commonly affected, but many other ash species may also be affected. It is spread from diseased to healthy trees by leafhoppers and other related sucking insects. Diseased trees exhibit an overall reduction in plant vitality that is similar to decline caused by environmental stresses.