Gypsy Moth

Female gypsy moth depositing an egg mass credit – Minnesota Department of Agriculture

Since its introduction in 1869, the European gypsy moth has spread throughout the northeast part of the U.S. destroying woodlands and causing millions of dollars in damages. Gypsy moth caterpillars consume large amounts of tree and shrub leaves in the spring. A single caterpillar can consume nine square feet of foliage per day. Entire trees or stands of trees can be defoliated when densities of the caterpillars are high. Gypsy moths do not directly kill the plants they feed on but defoliation causes stress leaving plants vulnerable to disease and infestation by addition pests.

Gypsy Moth Male
Gypsy Moth Male credit – Minnesota Department of Agriculture




Minnesota has been participating in a nation-wide effort to monitor and control populations of the gypsy moth since 1970. From 2012 to 2013 the number of male moths trapped in Minnesota jumped from 10,445 to 71,262 individuals, 90% of which were found in Lake and Cook counties. As a result of this boom in gypsy moth populations, the Minnesota Department of Agriculture enacted a quarantine of Lake and Cook counties beginning in July of 2014. The quarantine restricts the movement of materials that could be harboring gypsy moth eggs and/or larvae out of the counties in an attempt to slow the spread of the gypsy moth to other parts of the state.

To learn more about the gypsy moth quarantine click here.


Emerald Ash Borer

credit: Jeffrey Hahn, U of M Extension entomologist
credit: Jeffrey Hahn, U of M Extension entomologist

The emerald ash borer (EAB) is a non-native insect that is destroying ash trees in the Great Lakes region. The larvae of this forest pest kill ash trees by the tunneling under their bark. All ash species are susceptible to EAB infestation and the mortality rate is nearly 100 percent. EAB is primarily spread through transported firewood. Once an area is infested with EAB it is nearly impossible to eradicate. Early detection and rapid response can help to minimize and spread the cost to impacted communities over a number of years making control actions more feasible.

eabmap In August of 2013, an infestation of emerald ash borer was confirmed in the city of Superior, Wisconsin. A federal quarantine prohibits the removal of ash wood and ash residue and the movement of all hardwood fire wood outside Douglas County, WI. The City of Duluth has been actively monitoring ash trees in search of EAB since 2013. Currently, there have been no reports of EAB in Duluth or the communities of the North Shore; however, EAB is typically established in an area for several years before it is detected. Despite control measures that have been taken throughout the United States, EAB continues to spread. To learn more about EAB click here.