Something is chewing on my leaves.

[KSum]

Carefully inspecting the plants this morning I found one plant that has this going on..

I can't find anything crawling around, but I've also noticed some deformed leaves on other plants that look like the ends were cut off. No real damage can be seen, they are just missing about 1/3 of the end of the leaf.

Any idea what could cause what you see in the picture?

Thanks.