City of Prior Lake, MN
City of Prior Lake, MN

Emerald Ash Borer (EAB)


Residents can call Rainbow Tree Care directly at 952-767-6920 for a free inspection and quote.



EAB Resources

MDA EAB Program
Map of EAB in MN (MDA)

2015 Community Meeting Info

MN Dept. of Ag Presentation
University of MN Presentation


Discount Treatment Program
Ash Tree Identification (PDF)
Signs of EAB (PDF)
Firewood: Do's and Dont's (PDF)
Guide to Treatment

fish in a net


Prior Lake has contracted with Rainbow Tree Care for injection treatments and they are making the reduced pricing available to residents. Howmeowners can contact Rainbow Tree Care at 952-767-6920 directly and mention the Prior Lake treatment program for a free inspection and quote before beginning service (no obligation).


The Minnesota Department of Agriculture (MDA) confirmed an emerald ash borer (EAB) infestation in Prior Lake on Tuesday, August 25, 2015. 

EAB is an insect that attacks and kills ash trees and is spread through the transport of firewood. The adults are small, iridescent green beetles that live outside of trees during the summer months. The larvae are grub or worm-like and live underneath the bark of ash trees.  Emerald ash borer larvae kill ash trees by tunneling under the bark and feeding on the part of the tree that moves nutrients up and down the trunk.

What to do if you have a confirmed infestation of EAB?

  • Remove the tree: Tree removal or pruning should be completed during the EAB dormant period, October 1 through May 1.  By postponing removals until the fall, you can help reduce the risk of EAB spreading.  If the tree is left intact during the EAB Active Period, it can provide habitat for EAB adults to lay eggs.  But since the adults won’t emerge until the following year, if this tree or branch is cut and properly disposed of during the EAB Dormant Period, any EAB that may exist in the ash material will be destroyed when the wood is destroyed.

    If removal is necessary due to hazardous conditions then chip at least the outer 1” of bark/wood on site and transport to nearest facility that can process the material.  Or transport at least outer 1” of bark/wood in a vehicle where it is 100% enclosed to the nearest facility that can quickly process the material.  Material should remain enclosed until it can be, at a minimum, chipped. Material moved during the EAB Active Period may release adults at any time during transportation into a previously un-infested area.

  • Treat the tree: It is best to begin using insecticides while ash trees are relatively healthy.  By the time that most people notice canopy dieback, EAB has already caused considerable injury to the vascular system of the tree.  If there is more than 30% canopy loss, treatment is usually not effective and it is too late to save the tree.

    Options to treat the tree include soil injection or drench, trunk injection, systematic bark spray and granules. Some of these are available for sale to homeowners. The MDA has information on insecticides for treating EAB.

    Two life stages of EAB are targeted by treatments: adult beetles and young larvae. Insecticides only work while they are present in the tree, and products are generally labeled for a one to two year of effectiveness.  Treatment will need to be repeated to protect trees if EAB are still abundant enough in an area to cause significant injury when the effective period ends.

    Contact a Certified Arborist or City Forester to evaluate treatment options.  If hiring a professional, ask to see their licensure as a Commercial Pesticide Applicator for category “E: Turf and Ornamentals”.

For more information on emerald ash borer, go to the Minnesota Department of Agriculture’s website.