Dede
IGR is insect growth regulator. We had a horrible flea problem last year and so did our 2 neighbors. We found out a new neighbor had moved in down the street from us and they had several outdoor cats. These cats came in our yards and brought the fleas. We all used Martin's IGR and nothing else. It solved the problem for all of us and our dogs. We purchased it from Amazon.com for less than $20 each. Like Dr. F said, it lasts for 7 months when used indoors but must be reapplied more often outdoors because the sun breaks it down. We each sprayed our yard twice and our homes only once.