About the Emerald Ash Borer
Emerald ash borers belong to the metallic wood-boring beetle family, named after the family’s characteristic metallic coloring. Emerald ash borers are metallic green, with a red-purple metallic abdomen, which is exposed when their wings are spread.
Emerald ash borers are native to Asia and are suspected to have arrived in the United States through wood packaging material in the 1990s. Ash trees in Asia have defense mechanisms against EAB, but in the United States ash trees have no defense mechanisms against the EAB with disastrous implications for US ash trees.
Emerald ash borer beetles lay their eggs in the bark of ash trees. When they hatch, these beetles bore into the inner phloem and outer xylem, which transport food and water throughout the tree. The EAB thus cuts off the tree’s vascular system.
Adult ash borers leave ash trees, leaving behind a distinctive D-shaped hole on tree bark. Woodpecker damage on ash trees indicates that EAB larvae are likely inhabiting that tree because woodpeckers feed on EAB larvae.
Climate Change and EAB
Emerald ash borers cannot survive temperatures below -30 C and are poikilotherms, meaning they do not regulate their body temperature internally, so their body temperature and therefore metabolism depend on external temperatures. As a result, colder temperatures lead to slower development and ultimately slower spread of EABs. Because climate change is causing more mild winters, the EAB’s range in the US is larger than it would be without climate change.
Spread of the EAB
Anthropogenic spread of emerald ash borers via the transportation of wood has led to the rapid spread of EABs throughout the US. The spread of emerald ash borers without human caused spread would only be 2 miles per year.
Ash trees make up to 6% of America’s forest cover with over 149 million ash trees in Indiana alone. In the US there are 7 billion ash trees. There are 44 arthropod species that depend on ash trees for at least part of their life cycle and many species of fauna that depend on ash trees that are being affected by the major die off of ash trees as a result of the EAB infestation.
Effects of the Infestation
The EAB infestation is predicted to last 8-12 years with a 5000% increase in EAB every year until no ash trees remain and the EAB dies out.
Emerald ash borers are predicted to kill nearly all green, white, and black ash trees within the EAB’s range in North America.
Infected trees and regions should be quarantined reduce the spread of the EAB
Untreated wood and ash tree products cannot be exported from and within the quarantined counties and townships.
How to Stop the Spread
Ash trees can be treated to increase the chances of them surviving the EAB infestation.
Earlham wants to save as many ash trees on campus as possible to protect ash genetic diversity. Earlham’s efforts to conserve ash genetic diversity is part of a larger effort by the Great Lakes Restoration Initiative, which is collecting ash seeds.
Trees on campus that have already been killed by emerald ash borers are going to be cut down and if there happens to be any viable wood in them it will be used to make things that will be used on campus. Ideas include benches or a building at Miller Farm.
Photo from University of Kentucky