Ash trees that are dead or dying due to ash tree borers are cut down and then burned, chipped or buried. This keeps other trees from being affected. The USDA runs a program of releasing wasp species that attack borers’ eggs and larva. Insecticides are used on individual ash trees.
Ash tree borers lay eggs on tree bark. After hatching, larvae bore into the bark and feed on the tissue which transports water and nutrients throughout the tree. Without water and nutrients, the tree declines and eventually dies.
Ash tree borers are also known as emerald ash borers, or EAB. They are metallic green beetles native to Asia. While they sometimes fly from one tree to another, their spread is typically the result of humans transporting ash wood products from an infected area to a non-infected area. In 2002, EAB were discovered in Detroit and, as of 2015, have been found in many eastern and central states, as well as parts of Canada. Once infected, it usually takes five years for an ash tree to die, but death may occur in as little as two or three years. Since coming to North America, ash tree borers have killed millions of trees.