In June, 2002, the emerald ash borer (EAB), Agrilus planipennis was identified as the cause of ash tree decline and mortality in the Detroit metropolitan area. The scientific community now believes the beetle may have been present for up to 12 years in that local area before it was detected.
Homeowners and arborists in southeast Michigan initially attributed the loss of their ash trees to “ash yellows” (which is an insect-carried microbe that causes ash decline. The trees exhibited a top-down crown dieback, dense sprouting from trunks (epicormic shoots), and other signs of tree stress typical of ash yellows. The borer was discovered and thus put the yellow dieback theory to rest.
The emerald Ash Borer has killed nearly 30 million ash trees. Losses are estimated in the tens of millions of dollars. More than 7.5 billion ash trees are currently at risk in the eastern United States.
