This atypically large black-and-white yellowjacket gets its baldfaced name from its largely black color but mostly white face. Additionally, it’s called a hornet because of its large size and aerial nest. Baldfaced hornets are a stinging insect found all throughout the United States.
Baldfaced hornets are social insects which live in aerial nests. The adults are represented by workers (sterile females), queens, and males (which develop from unfertilized eggs and usually appear in the late summer). Only inseminated females overwinter and do so in sheltered places.
The overwintering queen selects the nest site. This can vary from shrubs or vines at ground level to 66 ft or higher in trees. Nests may also be built on overhangs, utility poles, houses, sheds, or other structures. Nearly all nests are constructed in sheltered locations. At maturity, the nests can be quite impressive with sizes of up to 14 inches in diameter and over 24 inches in length. Often, nests located in vegetation are not discovered until the leaves fall in the autumn. Nests are not reused the next season.
CONTROL AND PREVENTION
If a baldfaced hornet nest is high up in a tree, control measures may not be necessary. However, if the nest is low to ground and near a heavily trafficked area or has been discovered by children, then Plunkett’s should be contacted to treat the nest with a residual insecticide. Nest removal is optional. Children should be prevented from throwing rocks at hornet nests because these insects defend their nests aggressively and the stings are very painful. A disturbed or recently treated nest should be roped off and avoided until activity has ceased to keep everyone safe.
Adult workers are about 5/8 to 7/8" long. The queens measure 3/4 to 1 and 1/8" long. They are colored black with a white pattern on most of the face, white stripes on the thorax and white bands on the last 3 abdominal segments. Baldfaced hornets build a grayish paper nest shaped like an inverted pear and attached to branches or a recessed sheltered surface on a building.
Baldfaced hornets are beneficial insects because they help control many pest insect species and spiders. However, if the nest is located close to the ground or near an occupied structure, then control is warranted.
A Plunkett’s pest management professional wearing a protective garment will apply an appropriately labeled aerosol or dust insecticide through the entrance hole at the bottom of the nest. For high nests, a dust stick or “bee pole” allows application of the insecticide from the ground or a sizeable distance away and gives added safety for the applicator. The nest may be removed, placed in a garbage bag, and discarded or preserved for display at a later time.