Rod from Manitowoc, Wi writes
Demon Max can have some knockdown properties, but it is not considered a contact kill product. It is a residual insecticide that once dry will last on the surface 90 days indoors and 30 days outdoors. However, this product is not labeled for gnats. You could use a product like Talstar P. You may want to look over our article on Getting Rid of Gnats for more information.
Answer last updated on: 04/10/2019