I was taking to a older gentleman the other day, he told me something that I never heard before, here goes.
He said he use to keep about 20 hives about 30 years ago and he put a small pill of salt on the landing boards and the bee's would use it, he said that the bee's would put the salt on pested like moth larve and other pest, I started laughing and he said "What the hell you laughing about,I'm serious". anybody ever heard of this? man I almost got my ears blistered by a old fart! he a good fellow and a dear friend , just thought i would check it out.