If we knew what it was we were doing, it would not be called research, would it? -Albert Einstein
Eastern Boxelder Bug (Leptocoris trivittatus) Found east of the Rocky Mountains
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 neighborhood too.
- 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 you can.
- 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.
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UP HOME Update: 02/24/15