With the concern about the Aisan giant hornet reports in Washington State, there have been dozens if not hundreds of suspected reports to county offices and our department from across Kentucky.
None of these were the Asian giant hornet, instead the photos or specimens were mostly European hornet overwintered queens. The European hornet is a large (1½-inch-long), impressive reddish-brown and yellow insect with amber wings. European hornet is a woodland species that builds its large paper nest in natural cavities, especially in hollow trees. Often nests are six feet or higher above the ground.
Occasionally, the hornets select a protected, undisturbed spot in a barn, attic, or wall void. To make the paper to build the very large nest, they strip bark from several types of trees and shrubs including lilac, rhododendron, and birch and mix it with saliva.
Like many other social wasps, these hornets will aggressively defend their nest. When away from the nest, but it will only sting when threatened. They work together to defend their nest against thing perceived as a threat.
An average hornet nest will have 200 to 400 workers by late summer and they are prepared to become aggressive if they feel threatened. The pain is about the same as any wasp sting but these hornets can sting repeatedly and attacks by many can be potentially dangerous, particularly to those allergic to bee or wasp stings.
Some of the insects act as nest guard; they will attack anyone who comes too close. If the nest is located where there is a threat of people being stung, especially if it is indoors, it is best to have it treated by a professional. An experienced pest control operator will have the equipment and knowledge to deal with it safely.
It is always easier to remove the nest in early summer when there are fewer workers and the nest is small.
If European hornets were not so aggressive, they might be considered beneficial.
They are insect predators that capture large insects such as grasshoppers, flies, bees, and caterpillars to feed their brood. As they begin to prepare for winter in the fall, their food preference switches to sweets.
Some will collect the tree sap that bleeds from the wounds, others may chew holes in tree fruit or grapes close to harvest, a few become pests around uncovered trash cans searching for sweet liquids.
Late in the year, if the nest does not pose a danger, then it may be best to leave it alone.
European hornet nests do not survive the winter. The workers will die by late fall. A few fertile females will leave the nest to hide in sheltered places until spring. They establish new colonies in early spring.
These are the ones being captured now and confused with Asian giant hornets. These overwintered queens are a bit larger than the workers they produce.
Where there has been a previous nest in a structure, it is important to seal holes that would allow wall voids and attics to be used again as nesting sites.
(Source: Ric Bessin, Extension Entomologist)
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