Status of the emerald ash borer,

Asian longhorned beetle, and

gypsy moth: Reports from the

public continue to help agencies

identify new infestations

Invasive species pose a continual threat to Minnesota's tree and forest resources. Over the years, you have likely heard much about the Asian longhorned beetle and the emerald ash borer. With this article, our intent is not to provide an overview of the biology, potential impacts, etc. of these species, but instead to provide an update on current status of infestations of these pests and highlight the importance of reports from the public about potential infestations.

Emerald Ash Borer 

By Mark Abrahamson  

Emerald Ash Borer

An emerald ash borer infested tree was discovered in northwest Shoreview July 21 after a homeowner noticed symptoms consistent with EAB and contacted the City of Shoreview. A city official visited the site and recovered a beetle that resembled EAB and promptly notified the Minnesota Department of Agriculture. The beetle was confirmed by MDA as EAB and subsequent visits to the site resulted in the capture of several more beetles from the tree and the discovery of an EAB gallery - visible with binoculars through a bark crack in the upper stem of the tree.

After confirming the tree was infested, MDA met with City of Shoreview and Ramsey County representatives and laid out a plan of action. As soon as Friday, the day after the tree was confirmed, the city was able to send out a letter to residents in the area informing them of the find and alerting them that state and local inspectors would be in the neighborhood soon to scout for more infested trees.  The following week, an assessment was made of all ash trees within a half mile of the infested tree.

At this point in time, the only tree in northwest Shoreview that can visually be determined to be infested is the very first tree to be discovered. While this does not mean that there are not more infested trees in the area, it may indicate that the tree discovered was also the first to become infested in the area. It may also mean that this is a fairly recent infestation, providing further credit to the owner who noticed the symptoms. How the tree became infested is not known, though it is worth noting that the tree is only half mile from interstate highway 35W and in other states the principal spread of EAB has been along travel corridors.

Once beetle activity has stopped for the year, the city and MDA will arrange for the removal of the known infested tree. MDA also plans to do some sampling of other trees in the area to get a better idea of the extent and age of this infestation. At this point in time, the quarantine boundaries for EAB (meaning wood being taken out of Hennepin, Houston, and Ramsey Counties is regulated) remain unchanged as this infestation does not appear to extend beyond the quarantine boundaries. If the situation changes, the quarantine boundaries may be extended.

Although it is disappointing to have EAB appear in a new location, it is fortunate that this appears to be a relatively recent infestation, giving ash tree owners in the area the opportunity to treat their trees if they want or to begin preparing for their eventual removal if not.

Early detection of any new plant pests can make the difference in a successful response effort to slow the spread and delay economic harm. MDA appreciates the help that green industry professionals and the general public provide by keeping an eye out for new pests.

Asian Longhorned Beetle   

By Bob Koch 

The Asian longhorned beetle attacks various species of trees, but has shown a preference for maples, elm, willow, and others. Fortunately, this pest has not been detected in Minnesota, but it has persisted and is spreading in other parts of the country. In June, 2011, an infestation of Asian longhorned beetle was detected in southwestern Ohio when USDA confirmed an infestation of Asian longhorned beetle in Clermont County. The initial report was made by a property owner who noticed unusual damage on three maple trees. Since then, survey efforts in Clermont County have identified 5,000 infested trees. Currently, 56 square miles are quarantined, including Tate Township and an adjacent state forest.

The value of reports from the public is a reoccurring theme throughout the history of Asian longhorned beetle in the United States. Established populations of the Asian longhorned beetle were first detected in the United States in 1996 in New York, when a property owner noticed large holes in his trees and reported what he thought was someone drilling holes in the trees. The drill holes turned out to be beetle emergence holes. In 1998, a Chicago parks worker found the pest in firewood cut by a coworker. In 2002, in New Jersey, a citizen reported a beetle seen on a tree. Infestations were found in a total of three New Jersey counties. In 2008, in Massachusetts, a citizen reported an unusual beetle seen in a tree. The Massachusetts infestation was found to be very large, with 110 square miles quarantined in the central part of the state and over 20,000 trees found to be infested. Additionally, a small infestation was also found near Boston in 2010. Federal, state and local efforts have resulted in the eradication of the infestations in Chicago, Illinois and Hudson County, New Jersey. However, efforts continue to contain and eradicate the other infestations.  

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Gypsy Moth

By Lucy Hunt 

Some invasive species are very difficult to find and can cause major damage for years sometimes before they are identified. Others, like the gypsy moth, have a simple, effective and relatively cheap detection tool that is used throughout the country to find and track moth populations. MDA has been monitoring gypsy moth activity since 1973 and uses the latest technology and science. The network of traps across eastern Minnesota lures and catches adult male moths, triggering ground searches and treatment plans.

The gypsy moth program historically trapped each county in Minnesota at least once every four to five years. Recent budget cuts have allowed the program to operate only in eastern counties where the threat of gypsy moth infestation is greatest so we are counting on citizen reports more and more to fill in the gaps. July of 2010 marked the first time in Minnesota a citizen properly identified a gypsy moth caterpillar and reported it correctly to the Arrest the Pest Hotline. All reports are investigated and the majorities are native, but nuisance, species.

As a major pathway of spread, Minnesota's nurseries play an essential role in finding gypsy moth when it is first imported from infested areas. Nursery staff are encouraged to protect existing stock by reviewing shipping certificates from infested areas, inspecting stock during unloading, holding that stock separate from other items, and contacting MDA with any suspicious caterpillars or moths. We are very proud of our nursery managers who stand as a first line of defense against gypsy moth.

MDA Regulatory Update 

Overall regulatory numbers since the last Regulatory Review was issued: 

• 25 inspections conducted 
• 29 firewood inspection conducted
• 3 compliance agreements we renewed
• 2 new compliance agreements were issued

Additional topics:

Commercial vehicle inspections were conducted in partnership with Minnesota State Patrol and USDA.  

The first inspection was conducted at a weigh station in Winona County.

• 224 vehicles went through a primary search.
• 9 secondary inspections were conducted
• No violations were found.

The second inspection was at a weigh station off of Highway 10 in Anoka County.

• 117 primary inspections were conducted.
• Two secondary inspections were conducted.
• MDA officials conducted an inspection of a firewood producer's vehicle. This firewood producer was aware of the emerald ash borer quarantine and avoided the EAB quarantine. This firewood producer gets a gold star.

MDA Certified Firewood

This certificate shows MDA has tested and certified the facility responsible for heat treating firewood. This firewood is safe from emerald ash borer and is allowed to move throughout Minnesota.

If certified firewood dealers would like to advertise using MDA's certified logo or have questions about advertising, please contact Liz Erickson at liz.erickson@state.mn.us.