Avenger Organics Avenger Natural Weed Killer is a non-selective, post-emergence herbicide that quickly and effectively kills weeds, grasses and broadleaves without causing harm to the environment. The active ingredient d-limonene (citrus oil) naturally strips away the waxy plant cuticle, causing it to dehydrate and die. Available in 1qt, 1 gallon and Ready-to use (24oz) sizes.