I'm assuming it's a caterpillar. The holes seem small for slugs (and none of the other plants look slug damaged - or damaged at all for that matter). I couldn't find any critters. They've left the bean pods alone so far, so can I just live and let live here? I don't want to use pesticides.
I have heard to mix emu oil with a little bit of surfactant and water will take care your bugsie problem - spray on your edamame's leaves and pods and wella you are totally organic. i hope this helps. since growing your own is not cost effective, but who cares about that, it's the joy of seeing something grows and produces - emu oil is expensive - i don't know if there is a cheaper version will do the same trick - I have never done it before - you can try and send us a report.
