 In a hot, dry year, slugs won't be much of a problem. But if next spring is cool and wet again, here are our best suggestions to reducing slug populations. This fall, consider baling or tilling in residue. Next spring, you can spray liquid 28% or copper sulfate broadcast on bare soil, and this will help. In crop, if you're going to spray either 28% or copper sulfate, you need to use low rates and lots of water to reduce leaf burn.