BALD-FACED HORNETS
The Bald-faced hornet (Dolichovespula maculata) is sometimes called the
white-faced hornet, but is actually a Yellow Jacket. It's easy to spot
since it's our only black and white Yellow Jacket. Its nest is a gray
"paper" envelope with several layers of combs inside. A mature nest is
bigger than a basketball, but pear-shaped, with the larger end at the
top and an entrance hole near the bottom.
A single, over wintering queen begins building the nest in the spring.
She lays eggs and tends the first batch of larvae that develop into
workers. These workers tend new larvae and expand the nest throughout
the summer. A mature colony can have several hundred workers by the end
of the summer. In fall, workers die and next year's queens find over
wintering sites.
Bald-faced hornets are beneficial, capturing insects (often including
other Yellow Jackets) to feed to their larvae. Though larger than other
Yellow Jackets, Bald-faced hornets are generally more docile. But they
can become aggressive and will sting when their nest is disturbed or
threatened.
A Bald-faced nest is usually constructed high in a tree. In these cases
the nest is best left alone. In fact, Bald-faced hornet nests are often
first noticed in fall when leaves drop, exposing the nest. By this time
the hornets are dead or dying, and the nest will not be reused.
Occasionally you will find a Bald-faced nest built on the side of a
building, in low shrubbery, or even in an attic or shed. Nests in these
sites will probably need to be eliminated.
Bald-faced Hornet Elimination
1. Treat the hornet nest as late in the evening as possible. Remember
that all wasps, hornets and bees are at rest when it is dark. Not only
will all the hornets be in the nest for you to exterminate (instead of
foraging for food some distance away) , you will be at far less risk
when they are resting. No one wants to treat a hornets' nest with
hornets dive-bombing their head!
2. When approaching the nest, move slowly so as not to disturb the
sleeping pests. If eliminating the nest in late evening is not possible
(forcing you to work in broad daylight), avoid crossing the obvious
flight path. You also do not want to cast a shadow across the nest while
you work.