If we knew what it was we were doing, it would not be called
research, would it? -Albert Einstein
Boxelder Bug (Leptocoris trivittatus) Found east of the Rocky
Western Boxelder Bug (Leptocoris rurolineatus) Found west
of the Rocky Mountains
The boxelder bug is a common pest of and named for boxelder trees
(acer negrundo) They are an annoying
pest in and around buildings. They belong to the family of scentless bugs
as they have no scent glands.
Adult bugs have an oval body shape measuring 1/2 inch long when fully
mature . They are a dull black to gray brown with brick-red markings along the edges of the
front wings. They lay eggs hidden in bark crevices and on seed pods in the
spring. The nymphs will appear in late spring to early summer and grow
rapidly. The nymphs (immature bugs) are red with black legs and wing pads. The earliest stages of nymphs can be totally red in color. You
may see adults and nymphs congregating together in the same place. The
adult females are the ones that overwinter and can produce one to two
generations per season.
The bugs preferred food is primarily the female boxelder tree but they
will also infest and feed on maple, plum, cherry, peach, pear and ash trees. They have also been
known to feed on fruit. The nymphs have a long beak which they use to
pierce plant leaves, fruit, soft seeds and suck the sap. The adults have
also been known to eat fruit.
In the fall we will see the adults swarming enmass on the sunny sides
of buildings. In particular they prefer white or light
colored surfaces and a southern exposure. You will also see them
clustering around the lower portion of tree trunks. At this time they are looking
for hiding places to overwinter in and they will get into your house if
they can. Other hibernating places are under loose bark, in bark crevices,
under loose siding on buildings, gaps under sills- pretty much anything
they can find.
In the spring on warm days they come out of hibernation and we again
see them in huge swarms on buildings, along fence rows, at the base of
trees, evergreens and foundation plantings. At this time they are getting
ready to fly to boxelder trees and deposit their eggs into bark crevices.
The eggs will hatch in 10 to 14 days.
What can we do to control boxelder bugs?
First we would like to state that the bugs are harmless. For any
sprays that we recommend please do test it on the siding of your house in
an inconspicuous spot to see if it will stain. A most
essential aspect of indoor eradication and prevention of boxelder bugs is
dusting cracks and crevices where they like to spend the winter.
- One method, unfortunately, is to remove any female boxelder trees.
Do remember that the bugs can fly in from other parts of the
- Building maintenance: Seal up cracks with a good silicone caulking
material. Reattach any loose siding. Replace or repair any loose,
bent or torn window screens. Check all exterior doors to make sure
they fit tightly. Replace or install new weather-stripping. They can
also hide in attics and wall cavities, so check areas these too if
- Spray with horticultural oil
when they first appear and wherever they are swarming. Mid to late
afternoon is when you can get the majority of them. If you are
spraying the trees themselves- don't use soap or oil on Japanese
maples as their foliage cannot tolerate it. Be sure to apply very
thoroughly getting into the cracks and fissures of the bark. You
want to smother as many eggs as you can. You can use a hose end
sprayer or a compression sprayer. One of the best times to treat
infested trees for boxelder bugs is during late summer while the
second brood of bugs are still in the immature stages and
concentrated on the host trees.
- Use a good insecticide soap
and follow the spraying instructions in number 3.
You can give insect soap more of a kick by
combing it with 70% isopropyl alcohol (rubbing alcohol) as follows:
mix insect soap as per package instructions but substitute the
alcohol for half of the water required. If using on plants test an
area first for adverse reaction. A pyrethrum
or rotenone spray may also be used to kill them. Wear a mask when
spraying with pyrethrum or rotenone, you don't want to inhale it.
Spray them 3 times once a day at 3 day intervals with any of the
sprays. You can use pyrethrum in the house. The good thing about
pyrethrum is it has instant "knockdown" or kill when it
hits the bugs. It won't persist in the environment.
- Use a shop vac to help eliminate any boxelder bugs
that you see inside your house. You can use it to get them outside
too. When you are done dump then into a plastic bag, seal tightly
and put them in the trash.
- For a non-toxic control products like Dri-Die used
to treat cracks and crevices or anywhere they can get in. Silica
aerogels are formed by combining sodium silicate and sulfuric acid
which react to one another to form the particles. They have the
ability to adhere to the insects waxy coating and dehydrate them. It
must remain dry to be effective. Silica areogels are not the same as
crystalline forms of silica therefore will not cause the lung
disease "silicosis." We don't want there to be any
confusion with that.
- Use diatomaceous
earth as a barrier on window sills and any other places they can
gain entry to your house. DE can also be used as a dust in cracks,
crevices and in wall voids. DE can also be used as a wettable powder
to spray on the bugs outside and inside. As it dries on them it will
begin to cut and desiccate them. Always wear a mask when using DE as
it can irritate the mucous membranes. Once it has
"settled" down it is harmless to everything but the bugs
that come into contact with it.
- Hot water (165-180F) applied directly to the clusters readily
kills them. You can use hot water in a compression sprayer to do
this. Another method to try is to get a hose adaptor to hook your
hose up to faucet that has hot water and use a hose end sprayer to
blast them with hot water. If you have access to the hot water
heater you can turn up the temperature but don't forget to kick back
down when you are done. Please do be careful.
- Our own Farmer Bob, king of the quack grass farmers, reminds us
that ducks can not only be useful for slug control they would also
love to devour box elder bugs! So if you can beg, borrow or steal
(no- don't do that) a duck by all means do! Turn them loose to earn
their keep on those #^%$%^ bugs!
- How about a very large sticky trap? You can't get more organic.
Since we know they like lighter colors why not use some old plywood,
poster board or whatever you can come up with. Paint it a light
color and coat it with petroleum jelly or something very sticky.
Place the trap wherever the bugs are swarming and you should be able
to eliminate a good portion of them! Place smaller traps wherever
they are trying to get inside buildings. When your traps fill up
just scrape them off and recoat them.
We do carry diatomaceous earth and Insect soap.
Copyright © March 1, 2000 - 2011 Golden
HOME Update: 11/06/13