|Color||European hornets have a brownish-black body with narrow to broad yellow bands on the abdomen.|
|Size||1/4 – 1 5/8″ long.|
|Appearance||European hornets are much larger than yellow jackets and, unlike most stinging insects, can be active at night. They have pale faces, two pairs of wings, six legs, long bodies, and antennae.|
Habitat & Nests
European hornets’ nest in hollow trees, barns, outbuildings, hollow walls of houses, attics, and abandoned beehives. Their nests will rarely appear freely suspended like the football-shaped baldfaced hornet nests. Nests that are not covered by an external structure have a brown paper envelope made of cellulose from decayed wood covering the nest. This feature distinguishes this species from large yellow jackets. Nests that are sheltered have little or no envelope covering their cells. Nests often have a foul odor, and when they are built-in attics, they can extend into living spaces. A mature nest has about 1,000 workers.
Colonies & Life Cycle
Fertilized European hornet queens spend the winter hibernating, and in spring, they emerge to establish new nests in aerial cavities with chewed up wood they have gathered. The nest starts out with only a few cells in which the queen deposit eggs and then feeds nectar and insects to the hatched eggs. The larvae mature, pupate in their cells, and then emerge as sterile female workers. These workers take over the responsibility of foraging for food to feed the young larvae, collecting cellulose to expand the nest, and protecting the nest from external threats. Typical food for the young include crickets, grasshoppers, large flies, caterpillars, and the workers of other yellow jacket species.
Later in the summer, fertile females and males begin to hatch. Fertile, mated females overwinter in protected sites such as under loose bark, in tree cavities, and in-wall voids of buildings and become the queens for the next spring. The workers and males die at the beginning of winter and do not overwinter for the following year.
European hornets are social insects and live in colonies that may contain between 200-400 members at their peak in September or October.
Stings & Damage
Because European hornets have smooth stingers, they can sting repeatedly during an attack. If the stinger becomes lodged in the skin at the site of the sting, it is important to remove the stinger as quickly as possible to curb the release of venom from the stinger. The venom makes the stings hurt, itch or swell for about 24 hours. A European hornet sting has the same risk of allergic reactions as with other insect stings. If you suspect you have these pests on your property, you should contact a pest control professional immediately.
In addition to the hazard created by their stings, the hornets can also do a great deal of damage to trees and shrubs because they strip the bark to get to the sap. They also use the bark fiber to build their nests.
Signs of Infestation
Seeing large worker European hornets is a sign of infestation. Finding nests in common areas such as hollow trees, attics, porches and inside wall voids are another sign of an infestation and removal may be necessary.
Prevention & Control
- Change exterior lights to yellow bulbs to reduce this insect’s attraction to your home or property.
- Remove any fallen fruit from trees, as it attracts these hornets.
- Regular inspections of your home by a pest control professional throughout the year is the best method to identify and prevent any issues with European hornets or many other pests. Pestfree365 provides regularly scheduled preventive services throughout the year.
If the nest does not pose a danger, then it is best to leave it alone. European hornet workers die by late fall, and the nests do not survive the winter. A few fertile females (new queens) will leave the nest to hide in sheltered places until spring when they will establish new colonies. In late fall, it is important to seal holes in structures that would allow wall voids and attics to be used again.
A Batzner Service Specialist will come to your property to identify the nesting sites and determine the proper treatment method. Depending on the time of year, it may be best to remove the nest when the queen is over-wintering and perform the preventative exterior treatment.