Ashgray Blister Beetle

greenish grey bug eating butterfly weed
Location: Georgetown, TX USA
June 30, 2011 9:06 am
I have / had a very nice butterfly weed plant that has become infested with these dusty greenish grey bugs that have stripped the leaves and flowers off of about 75% of the plant – I have not seen this bug before nor can I find it anywhere on the internet – please help if you can.
Signature: Melissa

Ashgray Blister Beetle

Dear Melissa,
We believe we have correctly identified your beetle as an Ashgray Blister Beetle,
Epicauta fabricii, based on photos and information posted to BugGuide.  We don’t know what your butterfly weed is, but here is what BugGuide indicates are the foods for the Ashgray Blister Beetle:  “Adult hosts: commonly on Leguminosae, including alfalfa, Baptisia, bean, pea, and sweetclover; sometimes attacks potato and glandless cotton.”  On the BugGuide Family page for Blister Beetles, it is indicated that “Larvae are parasitoids. … Epicauta (and other genera) larvae prey on eggs of grasshoppers.”  Insect populations do not remain consistent from year to year.  Some years see a surge in populations, and it can generally be associated with a plentiful food supply.  We can only speculate that perhaps last year there was a plentiful population of Grasshoppers, and that the eggs they produced allowed for a high survival rate among Blister Beetles.  Plants that are defoliated by insects generally survive and new leaves are produced by the plant to replace the lost leaves.  We would also caution you to handle Blister Beetles carefully as the beetles can produce a substance, cantharidin that is a blistering agent should it come into contact with the skin.

Ashgray Blister Beetle

Thank you so much! – Yes we had tons of grasshoppers last year and have them again this year so I know what to look out for – too bad for the adults because I would like them to eat all the grasshoppers they can but I want to try and save my butterfly weed!
Thanks again!

1 thought on “Ashgray Blister Beetle”

  1. I have a huge population of them in Southeastern Nebraska. They are eating all the foliage on my potato plants. No sign of grasshoppers.


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