A few weeks ago the crew leaders
for Youth Outdoors attended an Emerald Ash Borer (EAB) identification and
control seminar at the Fort Snelling State Park on the Mississippi River. The
crew learned many important details on identification of insects, the damage they
cause, as well as the trees that they affect.
They also discussed the critical state of Minnesota’s forests and the potential damage EAB has to harm them, as well
as best practices for dealing with them
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| Emerald ash borer galleries |
Emerald Ash Borers are an invasive species
from Asia that were first discovered in the United States in 2002 in Michigan.
They are small metallic green insects, roughly the shape of a grasshopper
without the large hind leaping legs, or an elongated teardrop shape. Adult
insects are approximately the length of a penny, they spend their first year of
life as larva and during this time they create s-shaped tunnels called
galleries in the sub-bark (phloem) of ash trees, which is easily visible after
peeling away the usually very dead bark where the eggs were laid. Finding these
galleries can be done by locating woodpecker damage in trees, or finding an
exit hole where an adult insect had left the tree.
EAB affects
all species of ash. Minnesota has the highest density of ash trees in the
country and ash are the most abundant tree species in the state. The high
population of ash trees in the state makes the control of EAB crucial to the
protection of our natural woodlands. Fortunately the cold Minnesota weather may help preserve many
of these ash trees, by beating back the population of the insect. EAB is not
hardy to -30 degree weather which is not at all uncommon in much of the
northern forests. Unfortunately for the Twin Cities, the wind chill
temperatures that may be experienced with some regularity in the dead of winter
rarely drop to -30 degrees and the well insulating bark of ash trees doesn’t
permit wind to draw cold deep into the tree.
On the
other hand, the Youth Outdoors, who work with Saint Paul Parks and Recreation,
now have the tools to identify EAB and to abide by regulations regarding it,
such as lumber quarantines and disposal practices necessary to combat the
insect. Hopefully they will not have to identify new problem areas in the Twin
Cities, but could now easily do so, and provide a regular set of eyes in the
deepest parts of our natural areas to keep tabs on the invasive insect.
