Insect
and Disease Fact Sheet Compliments of New Century
1-877-79TREES
Boxelder Bug
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Boxelder bugs may invade buildings, especially during the warm
days of autumn, to seek shelter sites for over wintering. They are attracted
to lights and will readily fly in open doors and windows. Indoors, these bugs
are a nuisance by their presence, produce a foul odor when crushed and, may
stain curtains with fecal matter.
Outdoors, they can be found clustering in large numbers on the sides
of trees, buildings and other structures. Large populations are often
correlated with long, hot, dry summers. During warm winter and spring days,
they may become active, moving from their hiding places into living spaces.
Although they do not cause, damage to buildings, clothing, food or humans,
populations are annoying. |
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Identification
Adult boxelder bugs are flat-backed, elongate, and narrow, about
1/2 inch long, 1/3 inch wide and dark brownish-black with three lengthwise red
stripes on the pronotum (area behind the head).
The head is black with the "beak" or proboscis reddish-orange and the
long, thin, four-segmented antennae, half as long as the body. Wings are thick
and leathery at the base and membranous at the tip. There are red veins
in the wings and the abdomen is bright red under the wings. The nymphs
or immatures resemble the adults in shape except they
are smaller, more rounded, wingless and bright red. Eggs are dark reddish-brown.
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Life Cycle and Habits During
the autumn months (around October 1), adult and large nymph boxelder bugs congregate in huge numbers primarily on the
bark of boxelder trees and then begin migrating to
a place for over wintering (frequently around foundations and windows). Only
full-grown adults over winter, moving to hibernation sites either by crawling
or flying. They may crawl from a nearby tree or fly about two miles to find
shelter. These bugs hide in cracks and crevices in walls, in door and window
casings, around foundations, in stone piles, in tree holes and in other
protected places. On warm days during winter and early spring, they sometimes
reappear on light-painted surfaces outdoors on the south and west sides of
the house, resting in the sun. |
Over
wintering adults leave their hibernating quarters with the coming of warm
weather (last week of March); arid females begin laying eggs (late April to
early May) in crevices of tree bark, stones, leaves, grasses
and on other objects near host plants. Eggs hatch in 11 to 19 days, with bright
red nymphs appearing about the same time new tree leaves develop. There are
five nymphal instars. The instars get progressively
darker red with each stage. In July, new adults lay eggs that result in
a second generation by early autumn. Boxelder bugs
feed primarily on the seed-bearing boxelder trees by
sucking sap from the leaves, tender twigs and developing seeds. Occasionally,
they have been observed feeding on ash, maple, plum, cherry, apple, peach,
grape and strawberries, causing some scarring or dimpling of fruits. However, boxelder bugs seldom develop in large enough numbers to
become a nuisance, unless able to feed on seed-bearing boxelder
trees. Apparently, they do little actual feeding damage to boxelder
trees. There may be one to two generations per year.
Control
Measures
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Prevention Since
boxelder bugs feed and reproduce primarily on pistillate (female) boxelder
trees, removal of these trees, especially around the house, would eliminate
nuisance populations. Some towns have outlawed pistillate
trees. However, adults are capable of flying two or more miles for suitable
hibernation quarters. If boxelder trees are
desirable for shade, ornamental beauty or other purposes, use only
propagation (cuttings) from the staminate (male) trees. |
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Eliminate
potential hiding places such as piles of boards, rocks, leaves, grass and other
debris close to the house. Rake leaves and grass away from the foundation in a
six- to ten-foot-wide strip, especially on the south and west sides of the
structure. Be sure to caulk and close openings where boxelder
bugs can enter the house such as around light fixtures, doors and windows,
unscreened vents, holes in walls around utility pipes or conduits, air
conditioners, heat pump lines and through the foundation. They are also
attracted to lights and can fly in open doors or windows. Screen all windows,
doors, crawl spaces, exhaust and roof vents and louvers. Clusters of bugs may
be killed by pouring boiling water on them. Be careful to avoid killing grass
and other desirable plants with boiling water.
Insecticides
Should
boxelder tree removal be impractical, treat the
young, exposed boxelder bugs "nymphs" on
the trees during spring and early summer to prevent potential large populations
and indoor migrations in the autumn. Some homeowners report effective, cheap
control by spraying a soap mixture on the nymphs and adults as they begin
congregating in late summer. The spray consists of about 1/2 cup of a laundry
detergent in one gallon of water applied by a hand sprayer or squirt bottle
directly on the boxelder bugs as often as necessary.
The soap mixtures kills only the bugs sprayed, but does not prevent others from
coming to the site. Test the mixture first on an inconspicuous spot before
application as it might stain cedar and other siding. Applications of Orthene, Sevin or Dursban sprayed to tree trunks, limbs and foliage are
effective. Sprays can be applied on foundation walls, sidewalks, fence rows,
etc. as boxelder bugs mature and migrate from the
trees. Cracks and crevices, wall voids and similar areas may be treated with
dusts and/or aerosols. When applications are needed on tall trees or large
areas requiring specialized equipment, it is best to employ a reputable pest
control firm. Indoor control is often difficult since the bugs may be scattered
throughout the house. Household aerosol pressurized sprays containing pyrethrins will give temporary control. When applying these
materials, fill the entire room with a mist spray and close it off for several
hours. Later, use a vacuum cleaner and/or broom and dustpan to pick up dead and
dying bugs.
Information obtained through the Ohio State Extension Factsheet HYG-2106-94
Insect
and Disease Fact Sheet Compliments of New Century
1-877-79TREES