I recently moved into a new house - a friends' house - with my 1and a half year old and 6 year old....was soooo excited and while we offloaded the first boxes my baby was walking in the yard. Within 5 min he was COVERED witg fleas! I have had an exterminator out, they've sprayed inside and out twice but they just don't die. Within 3 days they're back. I have a thatch lapa as well. I can't go outside and literally run from the car to the front door.. I've heard of diatomaceous earth.. ANY ADVISE???