The latest
wave of European immigrants to invade Missouri may be bugging
Ozarkers with their stingy presence, but scientists say the European
Hornets are actually beneficial to the ecosystem.
The European
Hornet is the largest of the vespid wasps in North America, growing
to 1.5 inches in length. It's the only wasp that is brown with
yellow markings, says Richard Houseman, entomologist at the University
of Missouri-Columbia.
Staff at the
University Outreach and Extension Office in West Plains received
more than a dozen calls last month from Ozarkers alarmed about--and
stung by--these hornets.
Colonies are
typically the largest and most active in the late summer months.
While hornets are not as aggressive as other wasps and normally
don't sting unless provoked, they will defend their colonies,
Houseman said.
This pest
is not new to the country. European Hornets arrived in New York
around 1840 and are found throughout the eastern United States
and Canada.
They prefer
forested areas like the Ozarks. Their nests are usually paper-like
combs that are brown in color, distinguished from the gray nests
of Baldfaced hornets.
``They came
over on a ship in the 1800s and have been migrating west for years,''
said Randy Saner of the Extension Office. ``They are big and exotic
looking, and we have received more calls this summer from concerned
people than we ever have.''
The reason
for that, Saner suspects, is the increased construction in forest
areas.
``I have a
feeling these hornets have been around here for years,'' he said.
``But since we have seen an explosion of new homes and construction
in the country, there has been more human contact with them than
ever.''
Despite their
reputation, European hornets are actually beneficial insects,
says Houseman. They capture caterpillars, grasshoppers, flies
and other wasps.
But they also
attack honeybees and will eat ripening fruit. The large wasps
can also damage landscape trees and shrubs, chewing the bark from
twigs as they seek sap.
Houseman recommends
that the hornets not be exterminated unless absolutely necessary.
If they must be controlled, the nest must be destroyed--an endeavor
best left to professionals.
For the do-it-yourselfers,
Houseman recommends working after dark when the wasps are in the
nest, using veils and a flashlight with red cellophane over the
lens. Chemical products, called wasp freezes, can also be used
to send a pressurized stream of insecticide into the nest opening
from 15 feet away.
Houseman warns
that the entrance hole of the nest should never be plugged--unless
you want some new roommates.
``The hornets
may chew a hole into the living space of the house,'' he said.
Large colonies
may reach a population of 1,000 during the summer. However, all
except the newly formed queens die at the start of winter. These
queens build small nests and start new colonies the following
year.
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