Emerald Ash Borer (EAB)

Emerald Ash Borer (EAB) is an insect that affects all varieties of ash trees by boring holes through the tree and bark.  The damage done by the insect progressively kills the tree. 

In the late 1990’s and early 2000’s EAB was virtually unknown.  In 2004, information began to circulate about this insect that was accidently introduced in the US from Asia.  The City of De Pere, as well as many other municipalities, began to discontinue planting all ash tree varieties (green, white, black; Mountain ash is not a true ash and is not affected) in response to the threat of EAB.  In 2009 EAB was positively identified on Green Bay’s north side.  In 2016 De Pere positively identified EAB in a location on our far NE side, with subsequent findings occurring in numerous other E and W side locations (see the attached map).

For a comprehensive look at EAB in the City of De Pere, including how many ash trees are in our City, what De Pere is doing to address EAB, what homeowners can do and much more, click here

Gypsy Moth

The Gypsy Moth has become well established in northeast Wisconsin. Populations of the moth in De Pere have risen to levels where we have contracted for an aerial spray in past years in areas of high populations. These sprays, done with cost share grants from and in conjunction with the WDNR, will help to keep numbers lower and limit defoliation in these select areas. They were not meant to eliminate the presence of the gypsy moth, but were used as one tool in its control. We will continue to evaluate moth populations and determine if an aerial spray is necessary.

Oaks are the preferred hosts, but many species of trees and shrubs are defoliated by the gypsy moth when the preferred host trees are not available. Other trees that are attacked and somewhat favored are: apple, birch, beech, cherry, hickory, maple, pine, poplar, spruce and willow trees. In De Pere we have trapped, surveyed, oiled and aerial sprayed to help monitor and control this pest. We will continue to monitor and help control the gypsy moth infestation, but other methods of locating and controlling this pest will require help from the city's residents. Please monitor your own trees and contact the City Forester with any outbreaks.

Gypsy Moth is a potentially devastating insect in our area and Spring/Summer is a great time to find and destroy caterpillars, pupae and moths. A popular method is to use burlap skirts on your trees. When the caterpillar, pupae or moth hide under the burlap, you should eradicate them at that time. Fall/Winter is a time to identify another stage of this pest. Gypsy moth egg masses can be spotted and dealt with in our trees at that time. For more information on this exotic pest in our area, please contact the City Forester at (920) 339-8362. You can also take part in the checking of burlap at a City park. Please contact the Forester if you can volunteer your time or have a group that could help out.

The following sites may have particular value in relation to the gypsy moth problem in Green Bay, the Fox Cities and Wisconsin.


Oak Wilt & Dutch Elm Disease

The City of De Pere has adopted an ordinance declaring certain diseased plants and trees to be a nuisance and providing an abatement procedure. The ordinance was adopted to assist in the control of Oak Wilt disease & Dutch Elm disease which has been detected in the past in Northeastern Wisconsin. It is strongly advised not to trim any Oak or American elm trees from April 1st - September 1st. If you have any questions or concerns, please contact the City Forester at (920) 339-8362.