The term "bagworm pesticide" refers to any pesticide effective in killing bagworms, a specific species of caterpillar. Homeowners have the option of purchasing either natural or synthetic types of this pesticide, with all varieties coming in spray form. Common brand names appropriate for this application include DiPel, Safer Caterpillar Killer and Green Light BT Worm Killer.
Bagworms are so called because, as they grow, they develop thick protective sacks around their bodies. They survive by eating the leaves of plants and often develop extremely large communities, making their appearance devastating for certain plant life. Among the most susceptible species of vegetation are conifers, such as arborvitae, cedar and juniper, because they typically can't reproduce lost foliage.
In early stage infestations, when bagworm specimens are still small, homeowners can deploy a natural bacteria called Bacillus thuringiensis to kill them. However, past this point, those still preferring natural pesticides should consider brand name options containing spinosad, such as Captain Jack's Dead Bug Brew or Garden Spray Spinosad Concentrate. For synthetic options, consider those brands for which permethrin, bifenthrinor or cyfluthrin are the chief active ingredients. Unfortunately, bagworm infestations become untreatable by mid-August, as pupating caterpillars are typically insusceptible to pesticides. At this point, the only remaining option is hand removal.