Prepare for EAB in Your Yard

Ash trees can be protected with a chemical treatment. Treatment can be used as a preventative measure before trees are infested with EAB or therapeutically if the infestation is caught in the early stages. Trees that are 10” in diameter and in good physical condition are considered ideal for treatment. By the time ash trees show the signs and symptoms of EAB such as woodpecker activity, bark splits and crown dieback, treatment may not be an effective option. Trees showing more than 30% crown decline are no longer good candidates for treatment.

Treatments are injected at the base of the trunk and trees must be re-treated every other year. Cost of treatment is based on the size of the tree and the overall number of trees on the property. This is an ongoing cost, but it can be more cost-effective over the long term versus the cost of removing and replacing the tree. Recent research has indicated you can protect a tree for 20 years for the cost it would take to remove and replace an ash tree. Treatment has the added benefit of protecting and preserving ash trees that provide numerous benefits to homeowners and the community.

The City has created an Ash Tree Injection Program which provides a discounted rate to residents to treat private property ash trees by a City contractor. Request an inspection from Rainbow Treecare, the City’s partner in our program. The treatment must be done every other summer and the price-per-diameter-inch cost has been predetermined based on the contract with the City.

If you would like to a use a different tree care company to help protect your ash trees, be sure they are a Minnesota licensed pesticide applicator. The Minnesota Department of Agriculture’s website can help you find the best tree care company for you.

If you opt to treat the trees yourself, be aware that the available chemical treatments at garden centers are not concentrated enough to protect an ash tree with a trunk diameter greater than 15” (48” circumference). Soil-applied insecticides can get taken up by nearby flowering plants and kill pollinators. In addition, soil-applied treatments should not be used within 25 feet of a storm drain or water resource such as a wetland, creek or lake.

Ash trees that are not treated will eventually die from EAB. Consider removing ash trees that are smaller than 10” in trunk diameter or that are in poor physical condition. Removing trees can be done pre-emptively or after a tree is infested. However, EAB infested ash trees become brittle and hazardous, which can increase the cost of removal. Plan removals between October 1 to May 1 when the adult beetles are not active. 

If you decide to remove an ash tree, do not lot leave any wood or brush debris onsite. All debris can be taken to approved wood utilization sites within current MDA quarantines. You can find approved sites in Dakota County on the MDA website. 

EAB can spread quickly within Lakeville and to other surrounding communities. To minimize the damage EAB has on our community forest, the City of Lakeville has adopted a Shade Tree Epidemic Pest Control Ordinance. This ordinance requires the removal of ash trees and tree material infested with EAB on private property.

For ash trees being treated, proper pruning can increase the overall health and condition of a tree. Ash trees normally produce a lot of dead wood in the lower canopy of the tree even when they are in good health. It is recommended that ash trees be pruned between October 1 and May 1 when EAB is dormant and there is a reduced risk of transporting the pest in the wood waste.

Once ash trees are removed, we encourage you to plant a replacement tree in your yard to help create the future tree canopy. It is recommended to plant for a large diversity of tree species on your property rather than a monoculture, in order to prevent a future pest like EAB from causing similar damage. The City’s Annual Tree and Shrub Sale, held each spring, is a great way to add trees to your yard.

There is a federal and state quarantine on counties in Minnesota with infested ash trees. Dakota County is under quarantine. The quarantine restricts the movement of ash wood material and all hardwood firewood. For more information on the quarantine, check out the MDA EAB quarantine website.