A typical treatment will average about 10-20 minutes. Larger yards may take longer to treat. Each treatment lasts approximately 21 days, at which time our team will be scheduled to treat your yard again.Our fine mist Barrier Spray kills adult mosquitoes on contact during the first application. The dried residue continues to provide protection for three weeks (21 days) when the mosquitoes land or feed on the vegetation. The following treatments will kill the larvae of the mosquitoes creating a safe and fun backyard.