Often confused for its relative the yellowjacket, the European hornet (Vespa crabro) is a stinging pest – and the only true hornet known in North America. While the hornets are relatively peaceful when left alone, they become _incredibly_ aggressive in defense of their nests.
With the ability to sting multiple times and to spit venom, European hornets should _not_ be treated lightly. In the event that you find yourself dealing with a European hornet infestation, steps can be taken to deal with the nest – but it is _not_ advised to attempt to remove the nest or kill the colony without the aid of a professional or professional-grade equipment.
Removing or destroying a hornets' nest yourself is not recommended; professional help is strongly advised.
The European hornet, though similar to yellowjackets and other wasps, can be identified by its large size; its yellow, red and brown pattern; and its tendency to be active at night, unlike other members of the vespid family. The hornets nest in hollow trees and high on top of buildings, and they can occasionally end up turning part of a house's wooden exterior into a nesting place. These nests, which resemble inverted teardrops, can contain hundreds of hornets – all of which will aggressively defend the nest if threatened. Nests are best dealt with at night, with the quick application of pesticides. Do _not_ attempt to plug a hornet nest entrance, as the hornets will create a new entrance/exit in response. It is strongly advised to consult a pest control professional before attempting to deal with a European hornet nest.
The European hornet, sometimes referred to as bell hornets, are the only true hornet species found in North America – having been introduced via European immigration to New York in the 1800s. They are the largest hornet found on the continent, ranging from 3/4 inch to 1 1/2 inches in size, and they have a yellow and red/brown striped pattern that causes them to commonly be mistaken for yellowjackets.
It is important to note that, unlike other North American vespids, the European hornet is active at night.
European Hornet Nests
The European hornet builds large nests in hollow trees far from the ground, or high on top of buildings. These nests, resembling dark-colored inverted teardrops, house colonies of hundreds if not thousands of hornets – all of whom will aggressively defend their nest if threatened.
These nests generally have a single entrance near the bottom of the structure, and the nests themselves are often less active at night than during the day.
In the event of a European hornet infestation, calling a pest control specialist to deal with the problem is _strongly_ recommended; while the hornets' venom is not deadly, their stings are incredibly painful and can lead to rashes and swelling for multiple days – a concern compounded by the fact that hornets can sting multiple times, and can spit venom. If this is not possible, any and all efforts to remove the nest or kill the hornets within should be done at night, when the nest sees less activity.
However, be warned that the hornets are known to post guards at nests, and "sees less activity" does not mean that the nest is empty.
Do _not_ plug the entrance hole of the nest, as this could potentially cause the hornets to burrow deeper into the home in an attempt to create a new entrance/exit. At the same time, be _extremely_ careful not to let the nest fall or rupture, as this will cause the hornets to anger and scatter, which can cause additional problems.
Wear a full-body wasp suit and use a long-distance insecticide spray intended for wasps: spraying from 15-20 feet away at night offers the best chance of quickly knocking down and killing the colony, after which point the area should be treated with insecticide dusts and similar products, to prevent the hornets from returning.