DELTA DUST 1 LB, Active Ingredient in Delta Dust s Deltamethrin. Delta Dust is a long term residual dust that kills crawling and flying insects. Delta Dust treats for up to 8 months when left undisturbed. Odorless and non staining, Delta Dust does not clump or absorb moisture. 1 lb of Delta Dust treats approx. 1000sq/ft.