Tobacco Hornworms

Subject: Giant Green Caterpillar!!
Location: The backyard. (Shenandoah Valley in Virginia, near Harrisonburg)
July 30, 2012 7:45 pm
Dearest Bug Man,
You are looking at two big ugly green caterpillars… I’ve already looked, and I like to see new bugs, but I gotta say – these big fat guys creeped me out a bit.
What ARE these creatures? I noticed something was eating my bush moon-flower leaves and when I started turning over leaves this is what I found! I’ve never seen this mammoth before… and they cleverly blend right in with the plant. I tried looking up ’giant green caterpillar’ and it might be some kind of horn worm, but I’m not sure.
I captured them and isolated them with their leaves under a big plastic storage thingie to see what happens…… Do I want to know? What do they turn into? Can I spray my moon-flowers with Neem Oil? I don’t want to get rid of a perfectly good bug, but they’re eating my beautiful moon-flowers!! I’m in VA in the Shenandoah Valley, and so are the bugs!
Thanks so much,
Virginia Caterpillar Warden
Signature: Virginia Caterpillar Warden

Tobacco Hornworms

Dear Virginia Caterpillar Warden,
These are Carolina Sphinx Caterpillars,
Manduca sexta, commonly called Tobacco Hornworms though they are generally found eating the leaves of tomato plants in home gardens.  We wanted to research your Bush Moonflower and most photos online indicate it is a Datura which is consistent with the diet of the Tobacco Hornworms of plants in the family Solanacea.  Adult Carolina Sphinxes are large brownish gray moths with yellow spots on the body.  Though they are not vibrantly colored, they are quite attractive.  A few caterpillars will most likely not harm your plant too severely.  We always leave caterpillars on our tomato plants despite their ravenous appetites.  See Sphingidae of the Americas for more information on the Tobacco Hornworms.

Wow!  Thanks Daniel!
You’re right about the moon-flower – it’s a Datura. If the Sphinxes like tomatoes they’ll love these plants because they are in the nightshade family.   I only found two, so I’ll keep my fingers crossed that I don’t get more and get my flowers ravaged!  They are only on one plant…. now I guess I’ll have to check everyday.
The Moon Flower plants are new for me and were sent as root transplants from Joplin MO.  They are still only about 1 1/2 ‘ and I don’t want to lose the blooms.  The flowers open in the evening and into the night and are stunning.
You’ve given me some great resources to learn more about the hornworms!
Thank-you so much!

3 thoughts on “Tobacco Hornworms”

  1. KILL THE CATERPILLARS!!!! They will destroy your Moonflowers. Especially since the plant is young. I had caterpillars buzz their way through my Moonflowers, eating the leaves and the blooms. I have two HUGE (2nd year) moonflower vines/bushes, and they just destroyed them. I then learned to use BTK insecticide. I’ll be spraying as soon as this season is over, next month,and then at the very beginning of next season. (I too am in Virginia….in Richmond). They also leave tons on black “waste” all over the place. They are AWFUL!!!!

  2. we have 10 of these same catterpiiers on moon flowers. were the eggs laid on the moon flower ? do they bury themselves? since this is sept 1 will they not hatch till spring?

    • Tobacco Hornworms do pupate underground, and we cannot predict when they will emerge because you did not provide a location. The further north you live, the better the chances are that a spring emergence is more likely.


Leave a Comment