cotyledons eaten off

i've got 6 tiny little cotyledon stage plants outside in pots, can't bring them inside

when i checked them this evening two of the plants had (ONLY) their 4 little starter leaves eaten away completely, leaving just a little stem. obviously those plants are done for.

what could've caused this? i checked all around the plants but couldn't see anything except some ants. i'd definitely like to prevent this from happening to my other plants if possible.

my guess is bugs

i'm sure it's bugs, though i don't know which bug or how to combat it... that's the advice i'm looking for

i put some beer out and rubbed a little soapy water on the leaves, hoping for the best...

thoughts?

I know this is an old thread but what ever happened? My guess is that it was asian beetles or leaf hoppers. You could try covering them with a 2 liter bottle with the bottom cut off next time. I've also heard that azamax or garlic spray works.
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