DATE:    8/26/99         
WRITER:  Dr. Clyde Gorsuch, ( 864) 656-5043
EDITOR:  Giles Singleton, (865)656-3876

Avoiding Pesky Yellowjackets 

     CLEMSON -- As we get into the latter part of summer, close
encounters of the painful kind with yellowjacketts will become
more common. From now until the first killing frosts,
yellowjackets will become more and more of a problem. Many times
you can sit down to a nice picnic lunch in the shade, only to be
driven off in a few minutes by very hungry, aggressive
yellowjackets. 
     While other wasps and hornets will occasionally be a
problem, yellowjackets seem to be the worst pests of this kind,
especially in late summer. During the spring and early summer,
yellowjackets tend to feed on caterpillars, worms, and soft-bodied 
insects. Also, early in the season, the number of yellowjackets 
in a given colony are fairly low. 
     A yellowjacket nest is started by a single queen in the
early spring. She will often take over an old mouse nest or other
cavity in the ground or rotting log. The queen builds a small
paper nest in the cavity, lays eggs, and tends the larvae that
hatch from the eggs.
     Once worker yellowjackets are produced, the queen lays eggs
and the workers do everything else. In the early season, most of 
the food brought back to the nest by the workers is partially-chewed
remains of insects, caterpillars, and worms. At this time
they can be considered beneficial insects because of all the
pests they kill.
     By mid-summer, the yellowjacket nest may contain several
hundred to a few thousand workers. In late summer, new queens and
drones (males) are produced. At this time, the food they eat
switches from a high protein diet for larval growth and
development to a high carbohydrate diet for the adults.
     By the end of the summer, the workers are especially
attracted to ripe fruit, soft drinks, or anything else with a
high sugar content. This is when yellowjacket-people encounters
become common.
     To prevent stings it is best not to try to chase the
yellowjackets away or to swat at them. It doesn't take too much
to aggravate the yellowjackets and cause them to sting. 
Yellowjackets, wasps, and hornets do not have a barbed stinger
like a honey bee. Their smooth stingers let them sting
repeatedly.
     If yellowjackets are a serious problem, steps must be taken
to find the nest and apply an insecticide treatment directly to
the nest site.
     One way to do this is to let the workers begin to feed on an
attractive food source like ripe fruit or sandwich meat. 
Carefully observe the direction that the yellowjackets take as
they return to the nest. Move along that line until you lose
sight of the yellowjackets. 
     Place the food in the open again and wait until they start
feeding. Follow their flight path again. Repeat this until the
nest site is located, then carefully mark the location and return
at night.
     Use a flashlight to locate the opening and then saturate the
entry hole with one of the aerosol wasp and hornet sprays. These
sprays are designed to shoot a stream ten or more feet and to
quickly knock down any adult insects that try to fly out of the
entrance. This lets you stay back far enough to get the
yellowjackets before they get you. 
     When yellowjackets are abundant, avoid the use of scented
soaps, shampoos, perfumes, after-shave and other cosmetics. Avoid
wearing brightly colored clothes as well. Shiny jewelry may also
attract yellowjackets. 
     People who are extremely sensitive to bee and wasp stings
should be especially cautious when yellowjackets are plentiful.
If you are one of these people, a professional pest control
company can safely treat any yellowjacket nests that are causing
problems. 
     Before using any pesticide, always read, understand, and
follow all label directions. 
     Additional information is available on the Entomology
Department web site at: 
http://entweb.clemson.edu/cuentres/eiis/medvet/mv3.pdf . -- 
Clyde S. Gorsuch, Extension Entomologist
                     *********************
     If you have questions or comments on gardening-related
issues, write to PSA News & Publications, Box 340129, A-101 Poole
Agricultural Center, Clemson University, Clemson, S.C. 29634-0129. 
     You might also want to look for other "Buds and Blooms"
columns under 1999 News Releases at: www.clemson.edu/agcomm . 
     Also check out Clemson Extension's Home and Garden
Information Center (HGIC) at: http://hgic.clemson.edu or 1-888-656-9988.
HGIC has information specialists on call  from 9 a.m.
to 1 p.m. Monday through Friday for information not covered by
the recorded messages and fact sheets.
                               END