... to kill mosquitoes, it is no longer registered for this use. Chlorpyrifos is effective in controlling cutworms, corn rootworms, cockroaches, ... and ornamental plants. It is also registered for direct use on sheep and turkeys, for horse site treatment, dog kennels, ... farm buildings, storage bins, and commercial establishments. Chlorpyrifos acts on pests primarily as a contact poison, with some action as ...