Leaning toward carnage…..
Dear What’s that Bug?
First let me say I adore your site, I have used it to identify many a creature in and around my home and there are more than a few spiders that own there lives to you and your unnecessary carnage pages. Talk about guilt bombs, more about that later. I purchase a lilac bush for my husband this year, he mentioned that they had a bush near his home when he was a kid and he loves the sent of the flowers. Earlier this month these worms or caterpillars showed up on the stems of that bush eating the leaves. When I first noticed them they were about an inch and a half in length and doing minimal damage. Now they are almost 4″ long and are destroying the little bush. I have been trying for days to identify them and find out if I can move them to an alternate food source. As I mentioned they are almost 4″ long without the horn. They have a voracious appetite and appeared on a Lilac bush in Mid August in Lake Lure, NC,. They most resemble a Sphinx Moth caterpillar to me, They have seven pairs of oblique blue gray stripes, but, lack the white nodules all over the thorax, they do have light green to yellow spikes on the top of the head? But not the underside. The horn is light green, not dark green or red. I don’t think it is a Tobacco or Tomato horn worm larva but then I have seen a number of what seemed to be Tobacco or Tomato Horn worms that were ID’ed as Sphinx Moth Caterpillars and vice versa so I am a little confused. I have attached some pictures. The first is just something I found interesting. I had taken some pictures in the morning of the 20th and by mid afternoon the greenies were significantly reduced in size. You can see the difference in the first and second picture. I believe it was because it we were having record high temperatures and have had little rain, I think they just lost a lot of fluid. I am considering a quick and painless execution if they do anymore damage. The execution is scheduled for Sunset on the evening of August the 24th, they seem to do the most damage during the night and I don’t think the Lilac can take anymore than that. I know you are busy and that you may not be able to get back to me in time to save either, but thank you for your time just the same.
First we want to say that the damage done by caterpillars to deciduous trees is not permanent as new leaves will grow back. This is some type of Sphinx Moth Caterpillar, and we are relatively certain it is the Great Ash Sphinx, Sphinx chersis. Larval host plants include ” ash, lilac, privet, cherry, and quaking aspen” according to Bill Oehlke. We hope we have convinced you to stay the execution.
Update: (08/24/2007) Carnage averted!
The execution has been called off. I woke up this morning and the caterpillars eating the lilac bush were gone! The plant is in a pot on the deck so I don’t know where they went, it does not appear that they burrowed. It’s as if they sensed my evil plan ( like I would have killed them) and scattered. There is very little of the lilac left, I hope it recovers. I would still like to know what they were for certain.. Thanks again.
Update: July 30, 2016
Thanks to a comment from Dominic, we have revisited this old posting, and we now believe this is a Rustic Sphinx Caterpillar based on images posted to Sphingidae of the Americas.