I first noticed a granular debris at the base of a Phlox and a Lobelia. Closer examination revealed a hole several inches up each stem. Opening the stems revealed a hollow tube in the middle, and this larval form in each. Hope this "lifestyle" info can help in making an ID. Thanks
It's a stalk-boring caterpillar in the genus Papaipema -
http://www.pbase.com/kenlebo/image/154731013
Thank you Flapdoodle. Do you have any idea how the "pith pellets" accumulate at the base of the plant? Entry hole about the same size as pellet. Caterpillar is headed toward top of stem, fills tunnel with body and has no room to turn around.
The caterpillar likely simply backs down its tunnel to the hole, poops, and then climbs back up to continue feeding...
Thanks.
