Can Dawn dish soap be used as an insecticide?

Yes, Dawn dish soap can be used as a homemade insecticide for many soft-bodied insects, but it is not a broad-spectrum repellent or a replacement for commercial products for severe infestations like German cockroaches or bed bugs. Dish soap works as an insecticide by breaking down the waxy outer coating of insects and disrupting their cell membranes, causing them to dehydrate and suffocate when sprayed directly. It is most effective against soft-bodied garden and household pests such as aphids, whiteflies, spider mites, mealybugs, scale crawlers, and young caterpillars. A common effective recipe is one tablespoon of Dawn dish soap, one tablespoon of vegetable oil to help it stick, and one quart of water, mixed and sprayed directly onto insects and infested plant leaves, ensuring thorough coverage of undersides of leaves where pests hide. For best results, spray in early morning or evening to avoid leaf burn and test on a small area first as some plants are sensitive. For indoor pests, a few drops of Dawn in apple cider vinegar can trap fruit flies by breaking surface tension, and soapy water can be used to wipe down ant trails to remove pheromones. However, Dawn alone does not kill hard-bodied pests like beetles, cockroaches, or bed bugs effectively, does not kill eggs, and has no residual effect once dry, so it does not prevent reinfestation. It is considered low toxicity to humans and pets when diluted, but avoid using antibacterial versions or strong concentrations that can damage plants. For lasting control, combine with sanitation and baits.