I have used this company for 10 years for a yearly extermination of yellow jackets in my yard. They use no chemicals that are detrimental to the environment, yet are amazingly effective in eliminating the nests within an hour of arriving. This last nest was formed in a hanging drape of a car cover over a railing...again, with calm attention it was quelled in under a half hour (which took that long to assure me that no one was going to be injured). I give them the highest rating for these frightening insects.