Emerald Ash Borer, EAB, is an invasive insect that was first found in Nebraska in the summer of 2016 when it was found in Omaha and in Greenwood Nebraska. Previous to this discovery, EAB was found in Missouri, Iowa, Kansas, and Colorado for the closest confirmed presence of this insect to Nebraska. Now that it has been found in Nebraska, there are more concerns for the residents.
One of the common calls I have received lately is determining if a poorly growing ash tree is infected by Emerald Ash Borer or if the insect on the tree is an Emerald Ash Borer beetle. It is hard to determine by looking at the tree if it is infected by EAB, but there are some signs to look for on your tree.
The signs of EAB infestation include suckering at the base of an ash tree, decline in the tree from the top of the canopy downward through the tree, 1/8 inch D-shaped exit holes along the trunk and branches, increased woodpecker damage, S-shaped Serpentine galleries underneath the bark of the tree. One of the first signs is that the tips of the branches will be bare of leaves. If you notice any of these symptoms in your ash tree, you should contact your local Nebraska Extension Educator.
As for the beetle itself, which would be flying as an adult now, it is a ½ inch long metallic green colored beetle. It has a bronze-purple color under the elytra. Elytra are the hard wings on a beetle. There are a lot of green colored insects that are often confused with EAB. There are tiger beetles, Japanese beetles, Green June beetles, green ground beetles, green stink bugs, and many other green borer beetles.
If you find any green bug on your tree make sure you bring it to your local Extension Office. The best way to transport insects is to scoop them up and put them into a zip-top baggie or old pill container or old sour cream or butter container and bring it in for proper identification. If you find an insect over the weekend or cannot get into the Extension Office right away, place your insect in the storage container and put it in the freezer to preserve it until a professional can identify it.
At this point, Emerald Ash Borer has only been found in Omaha and Greenwood in Nebraska. The recommendation is to wait to treat for Emerald Ash Borer until it is found within 15 miles of the tree’s location. There are chemical treatments that are effective against EAB. Homeowners can use a soil application, but this is most effective on trees less than 15 inches in trunk diameter. If the tree is larger, professional tree care companies can use a trunk injection. Wait until the insect is found within 15 miles before any treatment is done because the injections wound the tree and we want to wait as long as we can before we begin wounding our trees. A homeowner should also decide if the tree is in good health and a good location before beginning treatments. Planting ash trees at this time is not recommended. If you will not be treating your tree, it might be a good idea to start a new tree nearby to replace the ash tree when the time comes.
At this time, the only thing we can do to help with the ever-expanding problem is to not move firewood or wood products. Buy wood locally when camping and leave unburned firewood at the campsite when you leave. Also, determine if you have an ash tree in your landscape and watch the tree for signs of this beetle.