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Emerald Ash Borer Marching South Toward Kentucky
By
Laura Skillman
 PRINCETON,
Ky., (Dec. 13, 2006) – The emerald ash borer, a destructive pest
that has killed more than 20 million ash trees since it was
discovered in the United States in 2002, is marching toward
Kentucky. Homeowners and timber owners are advised to be aware
of this pest and the quarantines associated with it.
“The closest known infestation is in Warren County, Ohio, just
northeast of Cincinnati. Infested trees also have been found in
the Indianapolis area,” said Lee Townsend, entomologist with the
University of Kentucky Cooperative Extension Service. “We are
not aware of it in Kentucky, but it is clear that the insect is
moving this way.”
Since its discovery, the pest has cost municipalities, property
owners, nursery operators and forest products industries tens of
millions of dollars. Most of the devastation is in southeastern
Michigan where it was first discovered, but trees in Ohio,
Indiana and Illinois have also been affected.
The U.S. Department of Agriculture’s Animal and Plant Health
Inspection Service expanded its emerald ash borer quarantine to
include the entire states of Illinois, Indiana and Ohio
effective Dec. 1. The entire lower peninsula of Michigan is
already under a federal quarantine. The quarantines and fines
are in place to prevent potentially infested ash trees, logs or
firewood from moving out of areas where it occurs.
 The
USDA estimates that if emerald ash borer is not contained or
eradicated, it has the potential, over the next 25 years, to
cost state and local governments approximately $7 billion to
remove and replace dead and dying ash trees that can pose a
safety hazard in urban and suburban areas.
The adult beetles nibble on ash foliage but cause little damage,
Townsend said. The larvae (the immature stage) feed on the inner
bark of ash trees, disrupting the tree's ability to transport
water and nutrients. The adult beetles are metallic green and
about a half-inch long. The adults leave a D-shaped exit hole in
the bark when they emerge in the spring. Woodpeckers like the
larvae; heavy woodpecker damage on ash trees may be a sign of
infestation. Emerald ash borers only attach ash trees.
The borer extends infestations naturally as adults emerge from
the trees in which they develop and fly to new ones. The leading
edge of the infestation in southern Michigan expands gradually
(about a half mile per year). Large jumps are made when infested
firewood or nursery stock is moved long distances, Townsend
said. These account for big jumps in distribution. Often, the
strategy is to attempt to eradicate these infestations by
cutting all ashes within a half-mile radius of the infested
tree.
Emerald ash borer probably arrived in the United States on solid
wood packing material carried in cargo ships or airplanes
originating in its native Asia. Emerald ash borer is also
established in Windsor, Ontario. It was found in Ohio in 2003,
northern Indiana in 2004, and northern Illinois in 2006.
A concerted effort to stop the emerald ash borer or slow its
spread has been launched by state and federal officials.
Eradication efforts are under way in Michigan, Ohio, Indiana and
Canada to prevent small infestations from growing into large
infestations. In addition, quarantines are in place to prevent
infested ash firewood, logs or nursery trees from being
transported and starting new infestations. Research is being
conducted at universities in an attempt to understand the
beetle's life cycle and find ways to detect new infestations,
control adults and larvae, and contain the infestation.
Townsend said there are several things homeowners and timber
owners can do as well. The first step is to become knowledgeable
about the insect.
Confirm the identity of ashes in your landscape – be sure you
know what you have. Digital pictures of trees, especially of
abnormalities, can be kept as a record. Knowing about existing
damage can be helpful when watching for recent signs of attack.
There are some native ash borers, so there can be holes or scars
already present. These native borers attack damaged or stressed
trees, not healthy ones.
Be aware of quarantines from surrounding states so that you
don’t inadvertently bring the beetle into the area – firewood
has been a major source of spreading.
Think long term about new landscaping selections. The emerald
ash borer is not present at this time, but planting ash trees
now may be a gamble against the odds. There are a variety of
alternative species that can be used and they will not be
infested by the insect.
If you have ashes in the landscape, begin to think about your
long-term plan when the beetle arrives. There is no need to make
a decision now, but it will help to have given it some thought
rather than making rushed decisions later. There are some
insecticide alternatives but they require a commitment for the
life of the tree. Per tree costs increase with tree size and,
over time, the cost of protection will exceed the cost of
removal.
Some insecticides, available to homeowners, do have the
potential to protect individual trees from emerald ash borer but
will not eradicate infestations. Research suggests that the best
control will be obtained when treatments are initiated just
prior to or in the earliest stages of infestation. It is also
important to realize that treatments will have to be repeated
each year, Townsend said. In many cases, it may be more
cost-effective to remove and replace the tree.
There is a lot of valuable information available on the biology
of the insect, location of infested areas and economic
considerations to help guide decisions should the insect become
established in Kentucky. The UK Department of Entomology has set
up a Web site where information and updates on the emerald ash
borer can be found. The address is
http://pest.ca.uky.edu/EXT/EAB/welcome.html. |
Contact: Lee Townsend, 859-257-7455 |
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The UK College
of Agriculture, through its land-grant mission, reaches across
the commonwealth with teaching, research and extension
to enhance the lives of Kentuckians. |
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