The term "hornet" is often used to refer to many of the
wasps that build large papery nests. The most notable paper
wasp is the baldfaced
hornet, Dolichovespula maculata, and several species of yellowjackets
(Vespula sp.), which are really wasps. In actuality the only
true hornet found in the United States is the European hornet, Vespa
Baldfaced hornets are large, black and white, heavy-bodied wasps
about 3Š4 inch (20 mm) long. They typically build exposed, mottled
grey nests in trees or shrubs. Occasionally, the wasps will build
nests under roof overhangs, in attics, crawlspaces and wall voids,
or under decks or porches. The nests are constructed of a paper-like
martial formed from chewed wood. The nests are often described as
"football shaped", but they may exceed a basketball in diameter.
Yellowjackets are house fly-sized wasps with distinct yellow and
black markings and a few hairs. Yellowjacket nests are also constructed
of paper, though they are tan in color, much smaller in size compared
to the hornet nest and are usually found in an underground cavity.
Common locations for nests are in lawns, particularly in sandy exposed
areas, as well as at the base of trees or shrubs. Occasionally,
yellowjackets will nest in attics or walls voids of houses or storage
of Jerry A. Payne, USDA ARS
An individual hornet or yellow jacket queen begins building a nest
alone in the spring. Once a queen has produced enough workers to
take over nest-building and foraging duties, she remains inside
producing more offspring. The workers expand the nest, forage for
food, feed the young and defend the nest. Like other predatory wasps,
their diet consists mainly of other insects such as flies and bees.
Bald-faced hornets will also feed on their yellowjacket relatives.
They continue to enlarge the nest until fall when there may be 300-400
hornet, or 600-800 yellowjacket workers. Frequently, it is not until
this time that the nest is noticed, although it has been there for
many weeks, already. In the late summer, the colony produces reproductives--the
insects that will mate. The mated female reproductives will serve
as the next generation of queens in the following spring.The
male's main purpose is mating and they cannot sting. Nests are abandoned
by wintertime and the future queens seek shelter alone, in protected
places under tree bark, in old stumps, or sometimes attics. The
current year's nests are not reused the following spring.
in particular, may be late season pests around picnics, trash cans
and hummingbird feeders as they scavenge. The only way to control
this presence is to locate and destroy the nest, which is rarely
possible. As an alternative, keep all outdoor food and drinks covered
when possible. Trash cans should be kept covered or have a flap
over the opening. Defensive behavior occurs in response to nest
defense. If the nest is not in the immediate vicinity the likelihood
of stings is greatly reduced.
The first decision to make is whether control is actually necessary.
Two points to remember:
In spite of their reputations, hornets and yellowjackets
are actually beneficial because they prey on many insects that we
consider to be pests, such as cabbageworms. They also serve as food
for bears, skunks, birds and other insects. They also are pollinators.
Unlike honey bees, hornet and yellowjacket colonies die out
each year. If a hornet nest is built high in a tree, you may choose
to simply wait until the colony dies out in late fall or early winter.
The nest will slowly deteriorate from weather or from attack by
If a nest is located where people may be stung or if you (or others)
are hypersensitive to bee/wasp stings, then colony destruction may
be appropriate. Here are some points to consider as you decide how
to approach the problem:
Control is best achieved by applying a pesticide directly
into the nest opening. This can be done at anytime of the day, but
near dusk, most of the wasps are more likely to be inside the nest.
You can use any of the aerosol "Wasp & Hornet" sprays that propel
insecticide in a stream about 10-12 feet. Direct the spray into
the nest opening and then move away from the area in case any of
the wasps emerge from the nest. You may need to be repeat the treatment
on the following evening.
Long sleeved shirt and long pants may be worn when spraying to make
the applicator feel more at ease.
Do not hold a lit flashlight or stand near car headlights or other
lights. Emerging wasps may be attracted in that direction and sting
Do not pour gasoline, petroleum or other hazardous chemical down
a nest hole. This is extremely hazardous and environmentally unsound.
If the nest is in a wall void or other inaccessible area in your
home, you may consider hiring a pest control company to do the work
for you. If the nest is in a wall, it may be desireable to remove
it if convenient after spraying to avoid attracting carpet beetles
that can invade the home and attack garments made wool, silk or
fur. Yellowjacket traps (commercial or otherwise) have not shown
to be of any value in reducing a yellowjacket problem.
B. Bambara and Michael Waldvogel, North Carolina Cooperative Extension