Aprehend® spray barriers remain active for up to 3 months if the application is not cleaned or disturbed. This means that any bed bug crossing the barrier, even 12 weeks after treatment can pick up the conidia and go on to die. Spray barriers should be applied to areas not exposed to frequent human contact or sunlight. Application is most effective when the sprayed areas are left alone (no wiping or cleaning) until the infestation is eliminated.