The root-knot nematodes are a limiting factor in growing ornamental plants –roses, carnations, Shasta daisies, gerbera daisies, and many others. Three species·–Meloidogyne incognita acrita, M. javanica javanica, and M. hapla–are commonly found on ornamental plants in California. Steam sterilization of plant beds or preplanting treatments of soil with nematocides have been effective in their control.