I use it when I do coop clean outs, but don't go overboard with it. Never had a problem with mites - well, one mite on one hen but in a coop I don't use it in; so I'm assuming it's at least good for that. I also use it for fire ants hills. Love to see them dang fire ants squirm. I refuse to use any chemicals on this farm, especially in areas my birds can get to.
DE works by having microscopic barbed spikes. The spikes pierce the insect between the armored plates and dig in. The barbs prevent the spikes from pulling loose and the insects movements simply drive the DE deeper and deeper till death occurs.
So whats wrong with DE? Simple. There is another well known product that has microscopic barbed spikes. Asbestos. Asbestos causes cancer the same way DE kills insects. You breath in Asbestos dust. The dust gets into your lung tissue which is full of folds wrinkles and tiny tight places. The asbestos finds a fold and the spike pierces the lung tissue. The breathing causes motion, the spike goes deeper and the barbs prevent the asbestos from pulling free. It stays in the same place for years. After years of irritation and damage to the same spots on the lung tissue by the fibers, cancer begins.
Knowing that DE functions in exactly the same way, why am I the only person saying there is an obvious lung cancer risk?