Now that so much has been posted on the NET about yellowjackets, perhaps it
might be best to share something I (Adrian Wenner) wrote on the problem (it
won't come through too well on e-mail but should be legible):
 
YELLOW JACKET CONTROL
 
Yellow jackets (Vespula spp. - colonial wasps), can pose a severe problem
for people when these wasps aggressively seek food.  (Remember, though,
yellow jackets do pollinate plants, such as squash, and dispose of waste
matter and thus are not all bad.)
 
Early in the season meat is preferred; later they focus more on sweets.
Normally, they are an annual species, with colonies started in the spring
of each year by a single mated and overwintered queen.  As the season
progresses, nest sizes grow and can contain thousands of individuals by
late summer or fall.  In mild climates colonies can even overwinter.
Effective control measures vary according to the circumstances.
 
1)  At eating areas
 
In a backyard, wasps can be kept under control by diligent use of traps
(next section).  Public picnic areas, however, have wasps already locked
into the readily available food supply (messy previous picnickers).  Bring
along a fly swatter and eliminate the early arrivals - other wasps are then
not recruited.  Fortunately, individuals of many yellow jacket species are
not aggressive when not near their nest.
 
Wasps do not hesitate to go into soft drink cans or bottles, posing a
problem for anyone not paying sufficient attention to their activities
before taking another swallow.  Neither do they hesitate to ride along on a
meat sandwich as it is put into one's mouth.  Watch out, also, for wasps
attracted to meat covered hands, fingers, or utensils.
 
If one places an effective trap (next section) 20-30 feet upwind from the
picnic table, the foraging wasps, when shooed away by picnickers, continue
to go upwind past the picnic table and end up in the trap .
 
2)  Remote treatment
 
Yellow jacket bait traps have been used more than a century, with one basic
characteristic in design:  Wasps will fly into a funnel (sometimes quite
small) to get at the bait provided and then cannot get out of the
transparent or translucent enclosure that incorporates the funnel.
 
One can buy any variety of ready-made traps with a wide range of
effectiveness.  The following two companies (among others) have produced
successful traps:  Seabright Laboratories, 4026 Harlan Street, Emeryville,
CA  94608, (800) 284-7363 or (415) 655-3126;  Sterling International, Inc.,
P.O. Box 220, Liberty Lake, WA  99019, (800) 666-6766 [FAX: (509)
928-7313].
 
These commercial traps can become clogged with yellow jackets in a
relatively short time during severe infestations, and then one must remove
them.  The problem then arises that live wasps may still be inside and pose
a threat.  In that case, one can place the trap in a freezer or an ice
chest, wait until the cold immobilizes them, and then empty the trap.
Alternatively, the trap can be placed in a paper or plastic bag just large
enough to contain it.  One can then spray a very small amount of electronic
parts cleaner (e.g., Electric Parts Cleaner, CRC, Warminster, PA 18974;
(215) 674-4300; Electric Motor Cleaner, Berryman, Arlington, TX  76011),
one that contains 1-1-1 Trichloroethane, into the bag and close tightly for
a few minutes.
 
One can also construct a simple and safe trap at virtually no cost - an
example follows.  Start with a one gallon translucent milk bottle.  With a
razor blade, cut a couple of small slits downward from one point (three
quarter inch across at the bottom), a little more than halfway up the
sides.  Bend the point so formed inward.  Fashion part of a wire coat
hanger into a hook at the bottom and thread it through a small hole
punctured into the cap so that the hook will be down about halfway to the
bottom of the bottle when inserted.  Bend the top of the coat hanger piece
so that it can be suspended from the lid.
 
Fill the bottle about one-third full of soapy water.  Then pierce a small
piece of turkey ham, salami, or ham (small enough to go through the bottle
opening) with the hook and put the lid, hook, and meat in place in the
bottle's neck.  Hang the bottle in a tree or bush upwind from the area
where wasps are not wanted.
 
You might also dig a hole and place the bottle in the ground so the
dowiwind opening is at ground level (wasps often search along the ground
for food).  If no gallon bottles are available, a one-liter transparent
soft drink bottle should suffice.
 
3)  Nest location known (perhaps with more than one entrance)
 
If one knows the location of a ground nesting colony (e.g., Vespula
pennsylvanica), the entire colony can be exterminated quite easily by using
nothing more than soapy water.  Take care, though, because these wasps are
highly defensive of their nest, usually allowing one to get no closer than
about 10 feet before attacking.  Some people prefer to treat the colony at
dawn or late evening, when activity at the entrance is less than in
mid-day.
 
Fill an adjustable nozzle spray bottle with water, add one level tablespoon
of liquid detergent, and shake.  Set the spray nozzle on stream, approach
from downwind (also from downslope or protected by bushes, if possible),
and spray wasps (guards as well as departing and returning individuals) at
the nest entrance as fast as possible from a distance of 10-15 feet
(practice at a target first to improve aim).  Wear full protection,
including a beekeeper hat and veil, if possible.
 
Once all activity at the entrance has ceased, pour a bucket of soapy water
into the ground through one of the entrances and block all entrances with a
shovelful or two of dirt.
 
4)  A take home poison
 
When wasp infestations become severe, you may wish to use stronger
measures.  To reduce their numbers, one can lace a desired food with poison
after yellow jackets become committed to that source of food.  With this
method, timing and procedure are somewhat critical.
 
Expose marauding wasps to canned cat food, such as a shrimp and tuna
mixture.  Allow the number of foragers to build up into a "feeding frenzy."
 Then provide a second dish alongside the first, but one laced with a take
home poison.  Orthene (20 drops per small can of cat food)  or KNOX OUT
(trade name for a micro-encapsulated diazinon product; one-half teaspoon
per can).  Don't attempt to use straight diazinon, or the laced food will
be rejected).
 
 
 
Adrian M. Wenner
Prof. of Natural History, Emeritus
Univ. of Calif., Santa Barbara
Santa Barbara, CA  93106
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* Adrian Wenner        E-Mail   [log in to unmask]  *
* Department of Biology        Office Phone    (805) 893-2838 *
* University of California     Lab Phone       (805) 893-2838 *
* Santa Barbara, CA  93106     FAX             (805) 893-4724 *
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