I'll keep the injecting bugs in mind. The problem is that the frog's not striking at anything at all, and he's never had a waxworm, so he doesn't know they're tasty. I don't think he'd strike at those either.

The nematodes could have come from the plants even though I cleaned them off first and rinsed with bleach/water. Or maybe it was the leaf litter which was boiled and baked. I tried, but it must not have been enough. Thanks for the reassurance though.