Sunday, June 24, 2012

Emerald Ash Borer Threatens Our Community

A significant Emerald Ash Borer (EAB) infestation was identified in downtown Green Bay at the WPS corporate headquarters this past week.  Approximately 36 ash trees were reported to have been heavily infested.  This is the same location that a lone beetle was found approximately three years ago in a trap.

The emerald ash borer is not a threat to human health but it kills our native ash trees of any size, any age, healthy or unhealthy. The Village of Bellevue has over 1,000 public ash trees along streets and within park areas. Furthermore, it's estimated that one out of every five private yard trees is an ash.  In Wisconsin, our forests contain more than 770 million ash trees.

EAB: What it is. How it got here. How it kills ash trees.

Emerald ash borer is a metallic green, wood-boring beetle native to parts of Asia. It's just one of thousands of similar beetles found around the world. It does not kill the ash trees in its native range. In North America, it is an invasive pest that can kill all the different kinds of our native ash trees.

It was brought to the United States accidentally in the wood of shipping crates from China. It was first identified as the cause of ash decline and death in Detroit in 2002. Since then it's been found in more than a dozen other states and in Canada.

The larva (the immature stage of EAB) spends its life inside ash trees, feeding on the spongy layer of tissue just beneath the bark. This feeding destroys that tissue and stops the trees' ability to move water and nutrients back and forth from the roots to the rest of the tree. The tree starves and eventually dies.

EAB can kill an ash tree in just a few years or a little longer depending on the size of the tree. It is estimated that more than 50 million ash trees are dead or dying in the Midwest because of this insect.

Signs & Symptoms

The visual symptoms associated with emerald ash borer infestations are nearly identical to those we often see on ash that are infested or infected by other ash pests and diseases commonly found in Wisconsin.

For example, crown dieback can result from multiple stressors including drought stress, soil compaction or verticillium wilt just to name a few. Therefore, it is important to look for a combination of at least two or more symptoms or signs (see list directly below) when trying to determine the presence of emerald ash borer in your ash tree. If you see two or more of these please report your findings here.

Controlling EAB

Whenever making the choices for emerald ash borer (EAB) prevention and management decisions, homeowners and commercial industries should review the latest decision-making tools available to them. University research results suggest that some treatment products and methods are effective when made appropriately, although there is some uncertainty of the long term effectiveness.
View more information on EAB insecticide options.

If you have an EAB-infested tree that you would like to use as firewood, please note:
  • EAB larvae in a downed tree can survive and emerge from the firewood pile for up to two years.
  • Wait until late autumn to take down an infested tree.
  • Be sure you will use up all of the wood from that tree by spring.
  • If you cannot use all of the wood in one winter season, you are better off leaving the infested tree standing through summer. Then follow guidelines for wood utilization when finally taking the tree down.
For more information and to discuss ash trees in your yard contact the County UW-Extension office in your area.

EAB moves far by hitching rides

On its own, the beetle will only fly a few miles. However, it is easily and quickly moved to new areas when people move emerald ash borer larvae inside of infested firewood, ash nursery stock or other ash items.