The Emerald Ash Borer (EAB), Agrilus planipennis, is a beetle native to Asia. In North America it is seriously invasive pest species.
The adult beetle is dark metallic green in color, about half inch long, with a torpedo-shaped body.
EAB comes from eastern Russia, northern China, Japan, and Korea. Before June of 2002, it had never been found in North America.
EAB was first discovered in the US near Detroit in 2002, and probably came to the US from Asia in the early 1990’s. It is speculated to have come in ash wood used for stabilizing cargo in ships or for packing or crating heavy consumer products. Moving firewood from an infected area to an uninfected area caused the majority of the spread, despite the fact the insect can fly about half a mile.
In North America, it has only been found in ash trees, trees of the genus Fraxinus. Trees in woodlots as well as landscaped areas are affected. Larval galleries have been found in trees or branches measuring as little as 1-inch in diameter. All species of North American ash appear to be susceptible.
No. EAB infestations have been found in 19 states from the East Coast to the Midwest as of 2013
The most noticeable sign of an infestation is crown dieback, a reduction in the fullness at the top of the tree. Higher branches will die from a lack of nutrients, afterwhich epicormic branching, or low level atypical branching, may occur. Bark slits and small D-shaped emergence holes may appear where the adult EAB leaves the tree. Wood pecker damage is common on infested trees.
Recent research shows that the beetle can have a one- or two-year life cycle. Adults begin emerging in mid-to-late May with peak emergence in late June. Females usually begin laying eggs about two weeks after emergence. Eggs hatch in 1-2 weeks, and the tiny larvae bore through the bark and into the cambium - the area between the bark and wood where nutrient levels are high. The larvae feed under the bark for several weeks, usually from late July or early August through October. The larvae typically pass through four stages, eventually reaching a size of roughly 1 to 1.25 inches long. Most EAB larvae overwinter in a small chamber in the outer bark or in the outer inch of wood. Pupation occurs in spring and the new generation of adults will emerge in May or early June, to begin the cycle again.
We know EAB adults can fly at least 1/2 mile from the tree where they emerge. Many infestations, however, were started when people moved infested ash nursery trees, logs, or firewood into un-infested areas. Shipments of ash nursery trees and ash logs with bark are now regulated, and transporting firewood outside of the quarantined areas is illegal, but transport of infested firewood remains a problem. PLEASE - do not move any ash firewood or logs outside of the quarantined area.
No. Healthy ash trees are susceptible. When EAB populations are high, small trees may die within 1-2 years of becoming infested and large trees can be killed in 3-4 years.
EAB is now considered the most destructive forest pest ever seen in North America. The scope of this problem will reach the billions of dollars nationwide if not dealt with. State and federal agencies have made this problem a priority. Homeowners can also help by carefully monitoring their ash trees for signs and symptoms of EAB throughout the year.
Yes. Once a tree has an EAB infection, it will likely die within a few years, depending on the health, size of the tree, and the size of the EAB population.
The Chicago Park District has between 25,000 and 30,000 ash trees, about 10% of all trees in the parks. They are all expected to have EAB within the next decade.
Aware of the impending effect of EAB for more than six years now, the Chicago Park District has been already aggressively planting trees (about 2000 native, non-ash trees) with the potential loss of ash trees in mind.