Emerald ash borer (EAB) is a non-native, invasive insect that attacks and kills ash trees. It was confirmed in the Twin Cities metropolitan area in 2009 and in Scott County in August 2015. 

Scott County is currently under a quarantine by the Minnesota Department of Agriculture. This means people cannot transport any hardwood from Scott County to a non-quarantined county. Learn more on Minnesota Department of Agriculture website.

What is emerald ash borer?

Emerald ash borer is an insect that kills ash trees. It is spread through transported 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. Trees are killed by the tunneling of the larvae under the tree's bark. 

Residents can help slow the spread of emerald ash borer by not transporting firewood and by disposing of trees locally. 

To avoid transporting emerging beetles to non-infested areas, it is a best practice to avoid pruning and removing ash in emerald ash borer infested areas during the flight season (May-September). 

What are the options for ash trees?

Chemical Treatment

There are chemical options which have proven effective for protecting ash trees against emerald ash borer. If you desire to save your ash tree, you should begin treatment this spring. 

Select city-owned ash trees (within right-of-way and parks) will be treated by a private contractor. To promote proper treatment on private property, the city is offering bulk discounted rates to residents through a contract with Rainbow Treecare.

If you are interested in participating in the city’s EAB treatment program:

• Call 952-767-6920
• Email info@rainbowtreecare.com
• Visit www.rainbowtreecare.com/shakopee

The city has ensured Rainbow Treecare meets high standards in staff training and years of experience. Rainbow also has several commercial pesticide applicators and ISA-certified arborists on staff. Treatment offered through this program is a trunk injection of emamectin benzoate, which offers protection from EAB for 2-3 years.

How long/often will I need to treat my ash tree? 

Emerald ash borer’s population is expected to rise and fall in a matter of 10-12 years. Therefore, ash desired to be saved will need to be treated every one to three years (depending on chemical) during this time. After all the non-treated ash have died emerald ash borer’s food source will be limited, reducing its population. At this point, you should anticipate a longer time between treatments, every three to six years depending on pest pressure.

The Minnesota Department of Agriculture has the latest information about treatment options for homeowners on its website.

Removal

Emerald ash borer has been shown to kill 100 percent of ash trees not chemically treated. It is not recommended to immediately remove all ash trees you do not plan to treat, but you should prepare for it.

• Start a replacement tree close to the ash you plan to remove. If you have multiple, stage removals.
• Do not prune or remove a tree during emerald ash borer's active period (May-September).
• It is more expensive to remove a dead tree than living, this can be especially true in backyards.
• Keep a close eye on your ash trees since emerald ash borer-infested trees can go from looking a little thin to dead in a year or two.
• Contact an ISA-certified arborist if you start to notice a thinning canopy or cracking bark in the upper half of the tree.

What should I plant in replacement of my ash tree?

When replacing your ash tree, it is wise to incorporate diversity in your yard. This will reduce the likelihood of losing many trees when the next insect or disease comes around. See Tree Care for a list of recommended trees for Shakopee along with tree planting guides.

What is the city doing with public trees? 

The city manages all trees within the street right-of-way and parks. Public ash trees that meet a certain size, condition and placement criteria are being chemically treated to protect against emerald ash borer. The ash trees which do not meet these criteria are being removed and replaced over a period of eight years. About 40 percent of the 2,000 public ash trees are being treated.

See the Shakopee EAB Management Plan Summary to review the city's plan for treating ash trees infected with emerald ash borer.

For additional information on emerald ash borer in Minnesota, please visit the Minnesota Department of Agriculture’s EAB webpage.