Bug of the Week: Palo Verde Caterpillar

We have a small palo verde tree in our back yard that volunteered.

Last week we discovered it was growing caterpillars as well as leaves. Can you spot the caterpillar?

During the day the caterpillars either clutch twigs or hide under things like loose bark. They feed at night.


The prolegs (fleshy legs on the abdomen) are reduced in number, giving them an “inchworm” gait.

See how pointy the three true legs are in comparison to the prolegs (left side of photograph).

I haven’t identified the species yet, but they might become owlet moths in the subfamily Erebinae.

We’ll see what happens in the next few weeks.


  1. Terri Jones

    Yes, I just found my Palo Verde tree with an infestation of these caterpillars. Do you know what a good treatment would be to get rid of them? And I would be interested in knowing what the species is when you find out.

    Thank you for your guidance.

  2. Cheryl Andrews

    I have the same tiny caterpillars on my Palo Verde ‘Desert Museum’. These 5 trees are new plants barely planted 1 month ago. So the pest was imported. I live in St. George Utah. The 20 gal containers don’t show what State these trees come from (Arizona, Nevada or California). I’m going to start today with BT and see how the war goes. Great photos. At this point these caterpillars are very small maybe a 1/4 “ and when disturbed fall from the tree on a thread. Don’t know if that means anything.

  3. Roberta

    Someone else suggested BT. I found they went through their life cycles and disappeared fairly quickly.

  4. Terri

    I believe the species is the ‘web worm’. I tried Monterey BT Caterpillar Killer (from Home Depot) and after a few applications, I noticed that they were gone. Hope this is helpful.

  5. Roberta

    I had a similar-acting caterpillar on our desert fern tree (silk streaming down). It seemed to be feeding on the flowers, though.

  6. Alan

    I put two-sided tape (made to keep cats from scratching furniture) collars around the trunks and the will not cross it and they disappear over a week or so.
    No chemicals required.

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