storage problem

I store my small squares on pallets with 6 mill plastic underneath and I always had a problem with some sort of moth larve that place themselves on the underside of the pallet against the plastic.I find larve in the hay and it stinks and dusty, it ruins the bottom row and I was thinking about spreading lime or salt to deter the moths from laying eggs. I'm able to salvage most of it by taking a wire brush on a grinder to clean it up but it still has the smell and bad look. I was wondering if anybody has same issues and how to combat it, thanks for your time

storage problem