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Everything You Should Know about Emerald Ash Borers

Threats to your ash tree’s health may be lurking in your neighborhood or woodlot. As a property owner you can take steps to reduce the threat and spread of the emerald ash borer (EAB) by following these simple guidelines. Doing so will contribute to healthy urban and rural forests in Wisconsin and potentially in surrounding states. The emerald ash borer, first observed in Wisconsin in 2008, is a significant threat to the health of the state’s ash resource. Here’s what you can do about it:

• Keep ash that is infested with EAB in place – do not move it off your property.

• Keep hardwood firewood local – do not move your own from your property and if you are buying it, buy from a local or certified firewood dealer near where you will use it.

• Protect high value ash trees with products that are labeled for controlling EAB.

• Replace infested ash with other tree species. Further information on how to

Locations of EAB Infestations Information on the location of EAB changes quickly.

Laws Regarding EAB The emerald ash borer is regulated by the Wisconsin Department of Natural Resources (DNR) through Chapter NR 40, Wis. Adm. Code and by the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) in Chapter ATCP 21, Wis. Adm. Code.

It is illegal to move any life stages of EAB under NR 40 DATCP, however, allows certain exemptions for businesses authorized through a compliance agreement.

Management Options

Research has shown that EAB-infested trees may show no symptoms until they have been infested for more than two to three years. Assume that all ash trees within 15 miles of a known infestation are infested.

1. Treat with an Insecticide

Treat with an insecticide only if the tree is apparently healthy or less than 40 percent of the crown has died, is discolored or has sparse foliage. Research has shown that trees with more than 40-50 percent crown dieback do not benefit from treatment.

Treating with an insecticide reduces the population of EAB and prolongs the life of your tree. Treatment requires a long-term commitment. It is not known how long EAB will remain in an area, threatening the health of ash, thus several treatments may be required or treatments may be needed for the rest of the tree’s life.

2. Remove and Replace

This is an option for ash in all stages of health. Contact a certified arborist to remove trees in your yard and to appropriately process wood to prevent additional spread of EAB. Replace trees with a non-ash species suitable to your site.

Trees larger than 10 inches diameter produce more EAB and should be considered a priority for removal.

3. Do Nothing

Observations in states where EAB has been present for several years show that all ash trees are susceptible to infestation and mortality. If you take this option, expect your tree to become infested and die. Be prepared to handle the hazards associated with dead trees such as falling branches which may damage property or endanger life.

Disposal of Infested Ash Wood

• Keep the wood at your home and use it for firewood or mulch on site.

• Work with a certified arborist to properly dispose of infested material.


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