Saturday, October 3, 2009

The Emerald Killer

They are dying. The beautiful trees that provide shade on many US streets, providing both beauty and shade are dying; and we have the invasive Emerald Ash Borer to thank. The infection has already arrived in Canada as well as Michigan, Ohio, Indiana, Illinois, Pennsylvania, Missouri, Wisconsin, Maryland, West Virginia and Virginia.

The Emerald Ash Borer (EAB) is an invasive species native to Asia. Its scientific name is Agrilus planipennis. The adult body is about 7.5mm to 13mm long, with a green metallic body. It is not known how EAB arrived in the US, but it is suspected that they came with ash wood in ships oversees to stabilize cargo or packing heavy consumer products. Since their arrival in Michigan, it has spread throughout North America killing 50 million Ash trees.

Green Ash and Black Ash trees are preffered by this green goblin. The White Ash trees are often next, and then Blue Ash, which show some resistance. The EAB does not only feed on sick trees, but healthy trees of all stature. I'm not necessarily sure how the EAB differentiates between other trees, but perhaps the trees just feel like home once the larvae has hatched.

Female EAB lay about 75 eggs, up to 300 from early May to mid-July. The Adults lay eggs in crevasses in the bark. When they hatch, the larvae burrow into the bark and eat the cambium and phloem. The death of the tree follows soon after within two years.

For more information on the EAB click here