Keeping bees in the Philippines, fungi and rot seriously shorten the life of hive bodies. It is generally hot and humid here but at the moment it is the rainy season and, despite using marine ply and multiple coats of paint, I'm still getting fungal fruiting bodies developing on the outside of hives, meaning the inside is being attacked. I've just read an article on making your own wood preservative http://www.bearfortlodge.com/home-br.../#comment-3070 using borates. Though the author doesn't recommend using a borate/propylene glycol treatment around people and animals a borate/water solution looks attractive.
Does anyone have any other suggestions for a treatment that is safe to bees and proven to be effective in the kind of extremes found here?