What's That Bug? does not endorse extermination

Subject: Bug identificatio
Location: Boise, Idaho
July 1, 2013 3:02 pm
We live in Boise, Idaho and have an infestation of these small bugs. They can fly, but we see them mainly crawling. They are outside, but are also inside our house and camper.
Signature: bugged and curious

Elm Seed Bugs

Elm Seed Bugs

Dear bugged and curious,
This one was almost a stumper because this is a newly reported invasive, exotic species, the Elm Seed Bug,
Arocatus melanocephalus, a Seed Bug in the family Lygaeidae that was first reported in North America in 2012.  Even BugGuide does not have a photo yet, however, BugGuide does provide this information:  “Detected in sw Idaho, marking the first time it’s been spotted in the U.S. according USDA Native to south-central Europe” and “Invade homes during the summer to escape heat, and then stick around through the winter.”  Finally, BugGuide notes:  “One generation per year and adults overwinter. Doesn’t pose a threat to trees, despite their name — but does tend to enter houses and buildings in huge swarms.”  We generally take our identification needs to BugGuide first as it is such a comprehensive database for North American species, and though we suspected this was some type of Seed Bug, the lack of photo caused us to check other possibilities in vain.  Finally, we just did a web search of “true bug infestation Idaho” and we found a photo and a link to the Barrier Lawn & Pest Inc. commercial site with photos and a description.  There was a common name but no scientific name, and this helpful information is provided:  “The Elm Seed Bug is a new invasive species in Idaho, discovered in the treasure valley in the summer of 2012. … Elm seed bugs originate in south-central Europe, and are closely related in appearance to the Box Elder Bug, the only obvious difference is the size, with Elm Seed Bugs measuring at just under a quarter of an inch. Elm seed bugs are nuisance insects:  They don’t bite or cause damage, but become problematic because of their large numbers and tendency to enter homes. Elm seed bugs overwinter as adults, mate in the spring and lay eggs on elm trees.  The larvae feed on seeds (particularly of elm trees) in May-June, and become adults in the summer.  Like most true bugs, the Elm Seed bug has scent glands that produce an unpleasant odor when crushed.”  Additional searching led us to a pdf fact sheet produced by the Idaho State Department of Agriculture that has extensive information on the Elm Seed Bug.

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What's That Bug? does not endorse extermination
Location: Boise, Idaho
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26 Responses to Elm Seed Bug Infestation in Idaho

  1. Sarah Mikek says:

    I have had this bug in my home for at least the last 7 years. I live in Washington County. They drive me nuts. They mate butt to butt and leave little brownish spots on my window sills. As they mature, when you smash them, they smell like Listerine. I only want them dead!

    The link in the above article ” Idaho State Department of Agriculture ” is broken.

  2. Sarah Jennings says:

    This is our second summer in our home and true to this website tthese little annoying bugs are back. We didn’t see them all winter but they’re back. I live in nampa and am calling in a post control to handle then and other not so nice spiders. How ever it is great to finally have a name for this mysterious bug.

  3. Debbie says:

    I have also been battling these pests for several years. I’ve found the best time to attack them is before they’re old enough to fly and their outer shell isn’t hard enough protect them yet. I can see them migrate in herds across the alley, moving from my neighbor’s elm tree to my yard each spring. I use EcoSmart organic bug spray and it keeps the numbers down. Until everyone pitches in to eradicate these bugs, they won’t go away.

    • bugman says:

      Cooperation is a necessity with all forms of eradication of invasive species. Sadly, if you neighbor’s yard is a breeding ground for the Elm Seed Bug, you will continue to have problems if your neighbor does not get involved. Thanks for providing the timing information. The nymphs that have not yet developed wings are more vulnerable as they cannot fly away.

  4. Nicole says:

    Hi there,
    We have had trouble with box elder bugs infesting our house in the past but this year it appears we have a new enemy. Swarms of these obnoxious bugs are crawling on and inside our house. We have sprayed time and time again killing a good majority of them outside. It looks like someone dumped a bag of cereal all over our porch. However inside has been an ongoing battle vacuuming and spraying them with insecticidal soap. Our neighbors tree is half dead and absolutely covered in these bugs. They refuse to do anything about their dry weed patch they call a yard and their infestation of box elder bugs and elm seed bugs. Does anyone have any suggestions on who might be able to intervene? The pest problem is out of control and only getting worse.

    • Debbie says:

      You might want to try Code Enforcement (as a nuisance property complaint) or maybe the Dept. of Agriculture-Division of Plant Industries (I think they are the department that does mosquito abatement.)

  5. Gary says:

    I’m confused, I have a camper down elm tree (umbrella elm) and have never seen the bug on this tree? Is it a specific variety of elm? They are definitely all over the outside of my house and then find their way into the house as well as my neighbors house. This being the 3rd year we have been infested with them and I have not found anything that really kills them off? We have had the elm tree for 15 plus years so I don’t believe it is this tree. Any other advice or info on how to exterminate them indefinitely would be greatly appreciated.

  6. Gary says:

    We live in the meridian area off linder and Franklin road so if anyone is in that area and has any info on a solution I would love to know what it is.
    Thank you

  7. Jerry says:

    Live in north Mountain Home had elm seed bugs last year but this year is crazy they cover entire window screens you cant walk out the door and they are allover you, The property is ringed in piss elm’s (sorry never heard them called anything else) They are in total swarms.How do i kill them?

    • bugman says:

      We do not provide extermination advice, but perhaps one of our readers may have suggestions.

    • Gary says:

      There is no real pesticide for them you have to extensively spray the elms around you and constantly spray around your home every time you see the (probably every day I assume). I have found that the dawn ultra works to kill them on contact but there is nothing with a residual effect. 1tsp per gallon of water in a pump sprayer. You can also take an old bottle of those ones you connect to a hose and put a couple tsps in it and connect to a house to reach higher areas or for trees. GL from meridian Idaho we are infested too!

  8. Debbie says:

    I’ve also found that fly strips help keep the numbers down. The east side of my house is coated with these bugs, (especially in the heat of the day) and within 2 days I had 3 fly strips covered with them. I’ve also had to tape my windows shut to keep them from coming inside. They can squeeze through amazingly small spaces. I still recommend the EcoSmart bug spray. It is effective if you can spray them directly, but have found nothing to completely eliminate them.

  9. I ve had an infestation of these this week and used Bayer spectracide. And are seeing some results. We live in Boise next to Edwards Greenhouse. They are a big nuisance and are ecerywhere. Ill keep after them and talk with neighbors.

  10. Mary says:

    The Dawn Ultra works (Thank you Gary)! Please use that instead of the Bayer spectracide as it will kill honey bees. Hive collapse is a huge problem and we need to protect the pollinators and humans! Thank you!

  11. Tracie says:

    Are Box Elder Bugs and Elm Seed Bugs the same thing? I’ve gotten conflicting answers from anyone I ask. I have billions of Box Elders in my back yard because I have Maple Trees, I’m just wondering if there’s going to be a new annoyance creeping into my back yard! Just as a note I DO NOT exterminate the Box Elders, there’s no point in starting a losing battle since I have 5 Maples on my property that I’m not willing to get rid of, I like the shade too much!

    • bugman says:

      The Boxelder Bug is a native species and the Elm Seed Bug is a nonnative species introduced into North America from Europe. Both are classified as True Bugs in the suborder Heteroptera.

  12. SBJones says:

    These guys showed up last year (2013) at our place and were pretty bad in the 1,000 springs area South of Hagerman. This year we have millions of them. I’m not kidding, every morning there are piles and piles of dead ones in every outbuilding and hundreds of dead ones in every window seal. I have seen the ground crawling with these bugs like ant swarms.

    It would take aerial spraying to get rid of these things or introduce a natural predator. The whole Snake River is nothing but overgrown piss elms and will feed and breed these guys.

    • Debbie says:

      Over the years, the Starlings and Robins have acquired a taste for them in our area. The thought of an aerial attack concerns me because I am a beekeeper.
      I saw on the news the other day (I think it was on KBOI) that a pesticide company is trying to find what will kill them. You can submit your house as a trial area and they will do what they can free of charge. They are hoping to be able to add this bug to the list of what their chemical will kill.

  13. Jane says:

    We have these in Salt Lake City this year. Cats will eat the Box Elders, but won’t touch these. Womp womp. Guess I’ll have to keep flushing 20 of them down the toilet every day.

  14. Julie says:

    Yes! I am in Salt Lake City and just bombarded by them in the past few days! I am renting and my landlords seem not to think its a big deal when I texted them about it. When I asked if they would cover the cost to get a pest control service to come spray, they said it was the tenant’s responsibility to deal with pests indoors. They have no idea what a huge problem it is yet, until they come see. I didn’t either until I went outside this evening And saw the swarms all over the siding, the windows, and rain gutters. They drop on my head as I walk through my front door/overhang . I can’t afford the pest control co. I just had them come out for spiders in June, I can’t throw another dollar at pest control only 1.5 months later! Should I just ignore it and let them deal w this? And in the meantime, will vacuuming them off the ceiling and door frame work well enough to keep them from multiplying even further ?

    • bugman says:

      For the record, we generally don’t condone the use of pesticides, but there are situations where professional attention is required. You should check your local renters rights because in our minds, it is generally the landlord’s responsibility to deal with indoor problems as well as property problems.

  15. Debra says:

    Hi Julie…so sorry you have them now too. While you wait for your landlord to come around you can do a couple things that will help (as well as vacuuming them).
    Fly paper strips really attract them and a spray bottle with dish soap and water will take the numbers down a bit…they really hate the lemon scented. Both are inexpensive ways to keep your sanity a bit longer. They land on me too and it creeps me out.
    I think Bugman is right about your landlord being responsible unless it is specifically written in your agreement that you handle indoor bugs.

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