What's That Bug? does not endorse extermination

Beautiful Blue Bug
Sun, May 10, 2009 at 1:44 PM
These blue fellows showed up in late April, proceeded to make a love shack of my grapevines, and disappeared shortly after. A couple of weeks later my vines are covered with these cute, little yellow and black caterpillars. I’m assuming the two are related but I can’t seem to find them on any of the internet searches I’ve done.
Thanks for any info, Rebecca
Mesa, AZ

Western Grape Leaf Skeletonizer

Western Grape Leaf Skeletonizer

Hi Rebecca,
We are so happy to have your photos of the adult moth as well as caterpillars of the Western Grape Leaf Skeletonizer, Harrisina metallica , in the same letter.  According to BugGuide it is:  “Native to southwestern USA and northern Mexico. Occurs from California to Texas, north to Colorado and Utah ” and “Larvae are a severe pest in some California vineyards.”  A very similar species, the Grape Leaf Skeletonizer, Harrisina americana, is found in the eastern U.S.

Western Grape Leaf Skeletonizer Caterpillars

Western Grape Leaf Skeletonizer Caterpillars

What's That Bug? does not endorse extermination

18 Responses to Western Grape Leaf Skeletonizer: Imago and Caterpillars

  1. Betsy says:

    How wonderful to see these photos! My father and I spent many “bonding” afternoons wiping these little guys off the four grapevines in our Phoenix backyard in the 50s and 60s, but I never knew what they were. Thanks for the memories!

  2. Robert pevehouse says:

    How do I get rid of.them?

  3. Nina says:

    ARGH! They got me this year. They’re everywhere. My poor grapes…

    • bugman says:

      We feel your loss. We have no plums this year because of the spring weather and the lack of bees during the small window for pollination.

  4. Nellie says:

    These caterpillars are in my mom and dads grapes in Cathedral City CA. They sting when they get on your skin. Are there any reports of allergic reactions or side effects from them.

    HOW CAN I GET RID OF THEM???????

    • bugman says:

      We are sorry, we do not provide extermination advice. According to BugGuide: “CAUTION! black hairs of especially late-instar larvae may cause an allergic reaction.”

  5. Spectracide Malathion Concentrate mixed up in a Hudson pump sprayer. Send all these stinging little, vinyard destroying worms straight down to the hottest part of bug HELL!!! These evil creatures are everywhere. in my house, in my animals feed, everywhere. The Malathion did the trick, and for anyone out there who takes pitty on my choice to exterminate these creatures I say, “You lose thousands of dollars of grapes and feed, while finging them inside your home” then I’ll listen to your whining.

  6. Ken says:

    We have a lot of these bugs on our grape vine in our back yard here in Goodyear AZ. I went down to Home Depot and picked up a bottle of Ortho Flower, Fruit and Vegetable insect killer. It really works!! I will try and post a picture of the bottle.

  7. bobc635 says:

    Bingo!!! I was looking forward to some nice bunches to share with the grandkids but most of my buds fell off. Many leaves were being stripped and I saw the larvae. I tried thuricide but it was not effective. I cut off as many infected leaves as I could and sprayed the plants with a dishsoap solution. My fingers are crossed. I dont want to use insecticides as mentioned in other posts but may have to go there if prob persists. Thanks for the posts.

  8. Bobby says:

    That’s them! I thought they were something else when I saw them – and should’ve dealt w/ them when I first saw them, even crawling on the side of the house. These pests (oh! how these lil’ guys can’t be that bad ?) ate up our grapevines in a matter of a day or two! Literally skeletonized leaves, barely any remaining; no grapes! Diatomaceous Earth (DE) doesn’t seem to work. We’ve tried that. I felt bad just leaving them alone. Not again!

  9. HK says:

    My grapevines in Las Vegas, NV have been stripped clean for the past 3 years by these ugly things. Can I feed them to my 2 ducks without harming the ducks?

    • bugman says:

      To the best of our knowledge, they are not poisonous. The caterpillars have hairs which the ducks might find unpalatable.

    • Emily r says:

      We live in Vegas too and the last three years these guys have been everywhere!!! Have you found anything that works to get rid of them?? We tried to catch and get rid of the moths early this year and our grapes have been doing alright however I had to remove about 1/3 of the branches in the last week because the caterpillars are going to town…I got some spray from star nursery but I’m worried about using it around my kids…will the grapes still be edible if I spray them? assuming they survive??

      • Yes, if they make it. I’m dealing with the same problem in the same city for the same length of time. I’m trying not to lose this year’s crop (I lost last year’s). There are about 400 pounds of grapes on our vines; I don’t want to lose them. I tried BT last week, then picking them off all day Saturday, then Spinospad this morning, but they are covered again! I think I will go out and pick them off again tonight. I am still seeing the moths. I don’t know if I can save them but I am trying.

    • Pauline says:

      Me too, I’m very allergic to them. How do I get rid of them?

  10. Ann says:

    I’ve been getting these since I planted grapes a couple of years ago. I just cut off the leaves that have the most babies (they are usually clustered together in tight pods on the bottoms of leaves at first, so they are fairly easy to find even when they are pinpoint tiny). That seems to control them sufficiently. My friends with chickens say the chickens love them.

  11. MARK says:

    I cut off leaves with clusters of caterpillars, and also hand picked em, and probably saved my grapes, but only have 2 vines. Next spring, I’ll be ready with a bug net and capture the adults when I see em. I wonder if they might be capable of re-locating vines in future seasons, or if they are just 100% migratory? Other grapes in our yard show no signs of infestation (for now…).

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