- Home
- Departments
- Public Works & Engineering
- Emerald Ash Borer (EAB)
Emerald Ash Borer (EAB)
Emerald ash borer (EAB) is an invasive species of North America that feeds on ash trees. First found in St. Paul in May 2009, the EAB is native to the north-eastern part of Asia. It has also been found across many other states, including parts of Quebec and Ontario, Canada.
In their native area, EAB's are not known to cause much harm to the trees, but they are extremely harmful to our ash trees here in Delano. They will infest both healthy and unhealthy trees, and all species of ash are vulnerable to the insect. Small trees will usually succumb to infestation after one to two years, while larger trees can withstand three to four years. Trees that are infested and not properly cared for will eventually expire.
Please consult the information below, or the Minnesota DNR (Department of Natural Resources) website to educate yourself further on EAB's.
MDA (Minnesota Department of Agriculture) Report a Pest: https://www.mda.state.mn.us/reportapest
Delano's Emerald Ash Borer Management Plan (PDF) provides further details on the steps that the City of Delano is taking to manage the spread of the EAB.
Ash Tree Identification:
- Ash trees will tend to have branches positioned directly across from each other. It is common for branches of ash trees to expire and fall off, so not every branch, bud, or leaflet on these trees is going to have a partner.
- The leaves of ash trees are going to be compound (split down the middle by a woody stem) with about 5-11 leaflets. The leaflets could either be smooth or toothed (consisting of small points around the edges).
- Older ash trees can be identified by their diamond-shaped ridges on their bark. Younger trees on the other hand will have smooth bark.
Consult the links below for more information regarding ash tree identification:
- https://www.dnr.state.mn.us/invasives/terrestrialanimals/eab/idashtrees.html
- https://www.canr.msu.edu/uploads/files/e2942.pdf
Emerald Ash Borer (EAB) Identification:
- EAB's are very small insects that tend to be no larger than a dime. Their color is best described as green, metallic, and bright; while their dorsal abdominal surface is going to be a bronze/reddish color. Shape is going to be thin and long with a squared off head.
- Symptoms of Trees Infected by EAB's:
- Unusually high amount of woodpecker activity.
- Very small D-shaped exit holes and S-shaped channels that are only visible after removal of the bark.
- Epicormics shoots at the base of the tree.
Consult the links below for more information regarding EAB identification:
The best way to treat an ash tree infested with emerald ash borer (EAB) is to use an insecticide that targets the insect. Given the harsh expenses of yearly pesticide treatment, it is recommended that the value of the ash tree (location, health, sentimental value) is taken into account before insecticide treatment is taken. If you decide to remove an ash tree on your property, know that the City will not remove any tree that is located on private property. Please do not dump any removed trees at the compost site.
More information on treating infested ash trees:
Local Tree Treatment Services
Cousin Tree Care -$5/DBH for privately own trees
Just like any virus, it is important to make small adjustments to stop the spread of EAB. Here are a list of things you can do to help with EAB management:
- Don't move firewood from your property or carry it across state lines.
- Buy firewood from local sources and burn it where you buy it.
- Before spring, burn your remaining firewood supply to eliminate the chance of EAB spreading to live trees.
- Inspect your ash trees for symptoms of EAB (canopy thinning, increased woodpecker activity, D-shaped emergence holes, S-shaped galleries, and splitting bark).