personally, if they are softbodied pets (mites, springtails, slugs, aphids, ants, etc) i just use Diatomaceous Earth (DE). totally organic, even available in good grade, and absolutely destoys the little buggers. got rid of my aphid infestation in one treatment. also provides silica =D sorry to mention this in a thread meant for beneficial insects, but it seems to me if you can keep any crawlies out period it would be better than lady bug carcasses and spider webs all over the place