By: Stephen B. Bambara and Michael Waldvogel, Extension Entomology
Baldfaced hornets may be best
described as large, black and white, heavy-bodied wasps about �" 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. They construct a similar type of paper
nest; however, it will be tan in color, much smaller in size compared
to the hornet nest, and is 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 buildings.
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 which are 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
Yellowjackets, in particular,
may be late season pests around picnics, trash cans, and humming bird feeders
as they scavenge. The only way to control this situation is to locate and
destroy the nest, which is rarely possible. As an alternative, keep all
outdoor food and drinks covered, except while actually eating. (see Beekeeping
Insect Note #15, Reducing the Likelihood of Stings During Outdoor
Activities). Bee guards or a coating of petroleum based chest rub can
be used on hummingbird feeders where the insects land. 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:
Pest information and control
recommendations presented here were developed for North Carolina and may
not be appropriate for other states or regions. Any recommendations for
the use of chemicals are included solely as a convenience to the reader
and do not imply that insecticides are necessarily the sole or most appropriate
method of control. Any mention of brand names or listing of commercial
products or services in the publication does not imply endorsements by
North Carolina Cooperative Extension nor discrimination against similar
products or services. All recommendations for pesticide use were legal
at the time of publication, but the status of pesticide registrations
and use patterns are subject to change by actions of state and federal
regulatory agencies. Individuals who use chemicals are responsible for
using these products according to the regulations in their state and to
the guidelines on the product label. Before applying any chemical, always
obtain current information about its use and read the product label carefully.
For assistance, contact the Cooperative
Extension Center in your county.
Distributed in furtherance
of the acts of Congress of May 8 and June 30, 1914. North Carolina State
University and North Carolina A&T State University commit themselves
to positive action to secure equal opportunity regardless of race, color,
creed, national origin, religion, sex, age, or disability. In addition,
the two Universities welcome all persons without regard to sexual orientation.
North Carolina State University, North Carolina A&T State University,
U.S. Department of Agriculture, and local governments cooperating.
Last updated - December 29, 1999
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