I'm going to go with @Brandy and @Tarnagh 's suggestions and use diatomaceous earth. I already have a bag because I use it to keep spiders out of the apartment, so I wont' have to spend any money. Yay!
Never heard of the critter but I'll try to keep an eye out for it. I do have a big problem with flies because my (street-sized) trash & recycling bins are inside my patio (no other place for them).