Ralph from Severn, Md writes
When using Gentrol Aerosol IGR for drains, apply product into and around the downspout and catch basin area. This is done with the crack and crevice straw that comes with the product. Coat these areas thoroughly as fly larva develop in the scum buildup on the sides of drain pipes. Be sure not to run water down the drain after application until the product has dried completely. Repeat applications at 2 to 4 week intervals depending upon the severity of infestation.
Answer last updated on: 07/11/2017
