Ortho 12 oz. Orthene Fire Ant Killer. Don't let fire ants keep you from enjoying your lawn. Stop the takeover by killing the queen and destroying the mound with Ortho® Orthene® Fire Ant Killer. This powerful, easy-to-apply solution destroys the mound and kills the queen. It begins killing in 60 minutes, so you can get your yard back fast. One 12 oz. bottle of Ortho® Orthene® Fire Ant Killer treats up to 162 mounds. Simply sprinkle powder over the mound no need to water-in. Use it as a mound treatment for home lawns and around ornamental plants (including flowers, shrubs, and trees). Follow label instructions to determine how much product is needed based on mound size. For best results, apply product while ants are active. To keep fire ants at bay, use as part of the Ortho® 2-Step System with Ortho® Fire Ant Killer Broadcast Granules (sold separately) as a second step to prevent new mounds from forming for up to 6 months.