Asked on Aug 19, 2012

What are these bugs on my milkweed plant?

MARY ANNRhonda ClementsSherrie S


I saw these bugs all over the seed pods of our milkweed plants yesterday. They're still there today. Any idea what these are and whether they're bad for the plant?
15 answers
  • Walter Reeves
    on Aug 19, 2012

    They're (DRUM ROLL) milkweed bugs! These insects form clusters on milkweed plants, where they eat the seeds. Milkweed bugs have few predators because they concentrate in their bodies bad tasting compounds found in the sap of milkweed plants. Entomologists like to study and work with milkweed bugs because they are easy to raise in a lab, where they can be fed pumpkin seeds. In general, the insects are harmless unless you are trying to raise milkweed. They never eat 100% of the seeds so some milkweed plants always manage to survive, germinate and continue their existence.

  • Melissa G
    on Aug 19, 2012

    Thank you, Walter!

  • Sherrie S
    on Aug 21, 2012

    Walter, I plant milkweed because the Monarch butterfly cannot reproduce without it. Then those ugly bugs eat the milkweed that the monarch needs for reproduction. The milkweed is pretty nice looking until those nasty milkweed bugs take over but the plant always survives here.

  • Sue brigle
    on Aug 22, 2012

    I don't plant milkweed exactly, but I let a lot of it grow up on its own for the butterflies. I'm not much of a weeder anyway so the monarchs give me a reason to leave the milkweeds.

  • Dora Traynor
    on Nov 27, 2012

    They're freaking me out!!!

  • Elle
    on Dec 29, 2012

    I don't know about milkweed bugs, but most bugs (as much as 95%) are either beneficial or benign. The Golden Rule is: never kill a bug unless you know what it is AND it is causing serious damage. Everybody's got to eat something, so pick your battles wisely.

  • Camilla
    on Feb 3, 2013

    I too have a problem with these eating holes from the undersides of the leaves of my butterfly bush. Is there anything I can do to keep them away this spring?

  • Jamie Wade-Matlock
    on Feb 4, 2013

    These are a type of assassin bug that eat aphids that get on milkweed, I believe. They are good bugs.

  • Renee Norman
    on Feb 5, 2013

    I had these on tomato plants last summer. They didn't seem to do any damage to the plant or the tomatos.

  • Charmaine W
    on Feb 10, 2013

    They look like a Box Elder Bug. I have an infestation of them in the summer. I have a Box Elder Elm in my front yard. Seemingly, they don't eat a lot of the plants, they don't bother anything. They don't bite. They're not like having cockroaches. My cat loves them when they come in the house.

  • Sonya Combs
    on Feb 12, 2013

    Those ARE assassin bugs and they're beneficial if you have aphids and other bugs that they eat.... here is a link to a page with a picture of them and a list of what it eats and what attracts it. When I still had milkweed (aka butterfly weed) they're would be masses of these on it thankfully they do good and look good!! :) don't let the ontario location mess with you I live in Kentucky and have the same ones!!

  • Beth
    on May 30, 2014

    The aphids are the ones to get rid of, and fast! HD has a great spray for them. Follow instructions wisely! There is a special way to spray the plant, easy, and boy does it work!

  • Sherrie S
    on Jun 7, 2014

    I don't spray the milkweed because I'm afraid it might kill the butterflies. I have many butterfly plants but the milkweed is the ONLY choice for Monarch Butterfly propogation.

  • Rhonda Clements
    on Jun 12, 2014

    Milkweed bugs and monarch caterpillars eat different parts of the plant so they don't usually interfere with each other. Milkweed bugs have piercing mouthparts and suck juices from the plant. Caterpillars eat plant tissue. Anything you do to control milkweed bugs also kills the Monarch butterfly caterpillars feeding alongside them. Try picking the bugs off by hand or spraying them with neem oil when the caterpillars aren't around. Neem oil doesn't leave a toxic residue, so caterpillars that return later on won't be affected by it.Read more :

    • DORLIS
      on Aug 22, 2015

      @Rhonda Clements These guys come when the seed pods are forming and they destroy all the seeds in the pod. pick them off, blast them with the hose (just the pods), do anything to get them off because with them around, you loose the seeds

    on Jun 29, 2014

    I had planned on posting pictures of these same bugs but never did. Thanks for posting. Now I know!

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