Signs of emerald ash borer in Shawano County

The first confirmed report of emerald ash borer for the county occurred in the city of Shawano last summer. Since then, there has not been any other confirmed reports to the Wisconsin Department of Agriculture, Trade and Consumer Protection within the county.

You can stay up to date with Wisconsin Emerald Ash Borer (EAB) Detections Look-Up Tool found at http://datcpservices.wisconsin.gov/eab/index.jsp.

The confirmed presence of emerald ash borer in the county means homeowners of ash trees should be aware of what the emerald ash borer looks like. As adults they are small, only 3/8- to 1/2-inch long and 1/16-inch wide, metallic green beetles. They emerge from late May to mid-July and live for 3-6 weeks, so they may be visible on ash trees now. There are some insects that look similar, such as the blister beetle, so confirmation before treatments are done is recommended.

In addition to finding adult beetles, decline of ash trees can be an indication that further investigation is needed. It takes years for emerald ash borer to kill an ash tree. Before it dies, it will show signs of decline, such as canopy thinning and crown dieback, sprouting shoots at the base of the trunk or on main branches, or woodpecker damage. These signs of decline are not just specific to emerald ash borer but can be clues to investigate further.

Other signs to look for is the damage created by the emerald ash borer. Larvae, which are cream-colored with bell-shaped body segments, cause the most damage to ash trees by feeding on the cambial layer. While feeding on the cambial layer, they create distinct S-shaped tunnels or galleries under the bark. When large amounts of these galleries occur, the cambial layer becomes too damaged to transport water and nutrients through the tree.

When adult emerald ash borers finish maturing, they emerge from the bark, creating distinct D-shaped holes. Visit https://eab.russell.wisc.edu/ or http://www.emeraldashborer.info/index.php for information on identifying emerald ash borers. If you suspect you have emerald ash borer, please contact the EAB Hotline at 800-462-2803 for confirmation.

Homeowners with ash trees may want to treat their trees for emerald ash borer. However, there are some considerations. Currently, insecticide treatments for emerald ash borer are suggested only for ash trees located within 15 miles of a confirmed site, or for trees located within a quarantined area. That does not mean that all ash trees should receive treatment. Homeowners need to determine if the ash tree is valuable enough to justify insecticide treatments.

Things to consider are the overall health of the tree and its contribution to the property’s landscape as well as others. A tree that is infested with emerald ash borer should not be treated when the canopy has thinning greater than 50%. The Extension fact sheet “Is My Ash Tree Worth Treating for Emerald Ash Borer?” gives detailed information and can be found at https://eab.russell.wisc.edu/eab-news-and-resources/#Management_Factsheets.

There are insecticides available to homeowners to use to treat emerald ash borer. When using insecticides, read and follow all label directions. Depending on the circumstances such as the size of the tree, a homeowner may want to work with a professional, due to their access to specialized equipment and insecticides that are not available to the general public.

More information on insecticide treatments available to homeowners can be found in the Extension fact sheet “Homeowner Guide to Emerald Ash Borer Insecticide Treatments” at https://eab.russell.wisc.edu/eab-news-and-resources/#Management_Factsheets.

Homeowners can also remove ash trees, healthy or declining. If this is the option a homeowner chooses, properly managing the infested wood is important to preventing the spread. It is an option to work with a certified arborist and have them handle the removal of the tree and proper processing of the wood.

The Department of Agriculture, Trade and Consumer Protection also has a document discussing how to properly use ash wood titled “Ash Wood Processing Options for the Homeowner,” which is posted on https://eab.russell.wisc.edu/considerations-for-homeowners. Firewood is strongly recommended to be burned in the county it originates in to help prevent not only the spread of emerald ash borer but other invasive species as well.

If you are interested in hard copies of these fact sheets, they are available at the Shawano County Extension Office at the Shawano County Courthouse, Room 109, 311 N. Main St., Shawano. Owners of woodlots and forested areas should consult a DNR forester to develop a plan to help lessen the impacts of emerald ash borer.

Kimberly Schmidt is the agriculture agent for Shawano County’s University of Wisconsin-Extension office.