A few years ago I responded to the following problem, with a package that
got posted on the FAQ:
>I had noticed that my hive has been rather feisty as of late and was
>perplexed until I opened my hive the other day and was attacked by a
>yellow jacket!
>I looked inside for evidence of bee slaughter, and found a couple of dead
>bees with their abdomen removed. What can I do to beat off these pest
>before winter sets in (I'm up in Vermont, so I have less than a month to
>the first frost in my area. Some regions have already had a frost) and
>shore up the colony.
*********
I repeat here the writeup:
*********
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 are not all bad; they do pollinate plants, such as squash,
and dispose of waste matter.)
Early in the season meat is preferred; later they focus more on sweets [a
conclusion that needs testing]. Normally, a colony lives only a year,
after its start 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
conditioned to 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 do not attack 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 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, wasps seek out 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 the wasps, empty the trap into a
plastic bag, and keep tightly closed until they suffocate.
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, 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).
5) Trapping with heptyl butyrate
A new trap used on Santa Cruz Island, California in 1995 caught more than
10,000 yellow jacket wasps (Vespula pennsylvanica) per day during a
three-day period.
The trap is VERY simple. Adapt a gallon milk/water jug with screw top lid
into the trap. On the flat surface underneath the handle, cut out a 2" X
4" rectangle and cover the space with a screen by using masking tape (a
stickier tape would be better). On the two opposite faces, about half way
up the bottle, cut two sides of a triangle (1" long, apex up) and bend the
flap into the bottle.
Partially fill the bottle (about 1.5" deep) with a strong solution of soapy
water (teaspoon per quart), taking care to not have many bubbles above the
water surface. Then dip a pipe cleaner only a little way into pure heptyl
butyrate, insert it into the top of the bottle, and clamp it in place with
the screw top lid. In the morning place the bottle on the ground with
screen side toward oncoming wind. Soon a crowd of wasps will come from
downwind.
Heptyl butyrate is very expensive, but it can be diluted with ethanol.
Some suppliers have more reasonable prices than others. A reasonable
choice: Pfaltz & Bauer, Inc. 172 East Aurora St., Waterbury, CONN. 06708
(203) 574-0075 - a little over $70 for 100 mg in 1996.
Be careful and don't spill, though, unless you want the wasps everywhere!
Also, heptyl butyrate apparently does not have a long shelf life unless
refrigerated.
Adrian M. Wenner
Prof. Emeritus (Natural History)
Univ. of Calif., Santa Barbara
9/98
Adrian M. Wenner (805) 963-8508 (home phone)
967 Garcia Road (805) 893-8062 (UCSB FAX)
Santa Barbara, CA 93106
************************************************************************
* "...in the drift of the years I by and by found out that a Consensus *
* examines a new [idea] with its feelings rather oftener than with its *
* mind. You know, yourself, that is so. Do those people examine with *
* feelings that are friendly to evidence? You know they don't." *
* *
* Mark Twain - 1923 *
************************************************************************
|
