Yellow Jackets: Good or Bad for the Garden?

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ILLUSTRATION: TOM QUIRK
An adult yellow jacket.

Learn all about yellow jackets.

Yellow Jackets

Most of us view yellow jackets as major pests. However,
some of the species help us by feeding on aphids,
caterpillars and other garden pests, while the rest play a
beneficial role as nature’s cleanup squad. We’d probably be
neck-deep in dead meat without their help. Still, it is
hard to be grateful to these critters when they are
commandeering your forkful of grilled chicken or delivering
a painful sting. And unlike honeybees, these
yellow-and-black wasp relatives can sting repeatedly. That
sting, plus their “meat and sweet” diet, can add a certain
element of tension to fruit picking and fine dining in the
out-of-doors.

Most people wait until numbers build up before putting out
yellow jacket traps, but trapping in April and May is
actually more effective in many areas. Although yellow
jackets (Vespula species) are social insects like
honeybees, they use their nests for only one season. All
the workers and drones die off in the fall and
responsibility for propagating the species is left to the
newly hatched and fertilized queens. In late fall, the
queens crawl into forest leaf-litter or some other
protected site. Insulating leaves, snow and an ability to
“super cool” protect the ladies from sub-zero temperatures
all winter. Come spring, they emerge and start a new nest,
often in a mouse or vole tunnel. Until the first batch of
workers hatches, the queen must forage for all the food
herself, and this two- to three-week period is when she is
vulnerable to being trapped. Every queen killed now may
eliminate several thousand yellow jackets later in the
season. (The pa per wasps that nest under the eaves are not
usually picnic pests, and are great caterpillar hunters, so
unless the nest is near a doorway, it’s best to leave them
be.)

Weather during this spring period also may be a crucial
factor in whether a particular season proves to be a “bad”
yellow jacket year. A severe cold snap just after the
protective layer of snow has melted could kill off many
queens still in the ground, thereby reducing the number of
prospective nests. A prolonged wet spell could hamper the
queen’s ability to set up a nest or forage, resulting in
fewer bees per nest. On the other hand, a consistently dry,
warm spring allows huge numbers of dormant queens to wake
up comfortably and successfully go about their business.

Other natural factors also may be at work locally—one
summer night we had a black bear carefully search and
destroy at least eight nests in our one-acre orchard.
Nothing was left the next morning but holes in the ground
and a few forlorn bees. However, failing bears in the
neighborhood, spring trapping may be a more dependable
method of control.

Both homemade and commercial yellow jacket traps (available
at most garden stores) can be effective. One expert
suggests bologna and apple juice to attract the bees, and
others swear by tuna-flavored cat food. Some commercial
“attractants” claim to lure in the queens particularly
well. The best bet is to experiment for several seasons to
see what works most effectively in your particular area.
Whatever you use, empty the traps and refresh the bait
every few days. Yellow jackets dislike the smell of rotting
meat, including rotting dead yellow jackets. Place the
traps out of direct sunlight in an open area and away from
where you plan to be active. Random insecticide spraying
will do nothing to control numbers. However, a direct shot
can kill a nest of yellow jackets, if necessary. Work very
carefully at night when the yellow jackets are
home—and have an escape route planned!