Emerald Ash Borer - Eleven-year Cycle: From Introduction To Large-scale Ash Death

Eleven-year Cycle: From Introduction To Large-scale Ash Death

The Emerald Ash Borer infestation pattern is similar to a locust plague in that populations grow exponentially after it is introduced into an area. In approximately 11 years, it can wipe out all the ash trees within a sizable perimeter. A typical Emerald Ash Borer female will lay approximately 100 eggs during her 2-month life; 56% of these eggs on average will be female. In a typical scenario, each year the EAB population multiplies by a factor of 50. By year 9 of an infestation, the EAB population originating from this one female, will be nearly 1 trillion insects. In year 10 it will be 50 trillion. These insects will then move on and create an expanding wake of destruction.

In individually infested trees, it is difficult to see symptoms in the first 1–2 years of infestation. Typically in the third year after infestation, the tree will exhibit significant dieback. By the end of the 4th year after the original infestation begins, the tree will be dead. After 5 years (1 year after death) the dead ash trees will become brittle and start to drop major limbs. Because the volume of trees that die at one time is often so large, cities and homeowner groups are being caught unprepared and are not able to remove the trees because of the lack of resources as well as available removal services.