If your corn didn't have its second set of leaves it should be ok. As far as what ate it, that could be a lot of things depending on what kind of pests are in your area. As far as bugs on your corn I use Seven spray. I know it isn't organic but I'm 71 years old and it hasn't killed me yet.

Slugs could be a problem with corn, especially in wet springs. Insecticides like Sevin won't control them. The decision to use a slug bait is based on different things. Could be that if you reseed the soil will be dryer and the slugs will have gone deeper to seek damp soil. Set a pan flush with soil and pour a cup of beer into it to see if slugs are the problem. If they eat into the growing center of the corn plant they can destroy it.

Thank you both! It really helped :)