Weather Forecast


Minnesota trees found infested with emerald ash borer

The Minnesota Department of Agriculture (MDA) reported Monday that a multi-agency survey found 59 trees infested with emerald ash borer in and around the St. Anthony Park neighborhood where the pest was first discovered in May.

All 59 trees are within a half mile of the first infestation site.

Twenty-nine of the infested trees are on public property such as city parkland or rights of way. The remaining 30 are on private property. The City of St. Paul will begin removing the infested trees on public property this week. At the same time, city and state officials will contact affected property owners to coordinate the removal of infested trees on private property.

Given the limited number of infested trees, MDA and St. Paul officials believe the best approach in this case is to quickly remove all infested trees and carefully monitor nearby ash trees for possible signs of infestation.

"Our goal is to make it as tough as possible for this pest to become a Minnesota resident," MDA Plant Protection Division Director Geir Friisoe said. "We know from other states how difficult it can be to eradicate emerald ash borer, but we are encouraged that infested trees have only been found within a half mile radius."

While removal of infested trees is the most visible part of the EAB battle, the monitoring effort is just as important. This monitoring takes several forms:

-MDA is placing purple cardboard traps in ash trees around the city. These mailbox-sized traps contain lures that attract adult ash borers in the immediate area. The insects land on the trap and become stuck to its sticky surface. Workers remove the traps in autumn to see if any borers have been caught.

-Workers will select unhealthy ash trees on public property for use as "trap trees." Injured trees are a strong attraction for borers in the immediate area. Bark along a section of the trunk will be removed and, ultimately, the trap tree will need to be removed.

-Homeowners are asked to join the effort by watching their trees for signs of infestation. These signs include dieback of leaves in the upper third of the tree's branches, heavy woodpecker activity, D-shaped exit holes in the bark, S-shaped tunnels under the bark or water shoots up the trunk. Homeowners who notice these signs should contact their city forester or a local tree care company with a certified arborist on staff. More details can be found on MDA's website at

-MDA reminds homeowners that it is not necessary to remove healthy ash trees. Homeowners with questions about disposing of ash tree material should contact their city forester for guidance. Improper disposal of infested ash material could accelerate the spread of EAB.