Pearlite degrades into fine white sand, which may explain why bugs don't like it. Personally, I'm getting better results than ever using a specific type of kitty litter.
@RM3 told me about calcined clay & it rocks! I like it so much, I mixed 100 lbs into my raised garden today. Heavier than pearlite & lighter than sand. It's perfect for soil.
Special Kitty all natural clay from wal mart. $4 for 25 lbs