Doktor Doom Spider Mite Knockout features a high-concentration of the naturally occurring insecticide pyrethrin, a very effective substance used to control aphids, spider mites, whiteflies, leafhoppers, Japanese beetles and more. Its one-fifth percent pyrethrin concentration is 10 to 20 times that of comparable pyrethrin-based insect control products. This powerful spray can be used indoors and out and is safe to apply on food crops up to one day before harvest. 16oz Aerosol Spray Bottle.