Re-infestation of nematodes is usually caused by soil that has already been infested with nematodes and brought back to an already treated area or brought into an area by someone or something that has infested soil attached. Most nematodes are microscopic and do not move more than a meter on their own during their lifetime. The way that most nematodes are spread is by a person simply walking with infested soil stuck to their shoes, a vehicle with infested soil on the wheels, plants or top soil from a nursery that has already been infested, water runoff from other areas around, animals carrying a plant, bug or other animal with infested soil on it, amongst many other forms of travel for microscopic organisms. It is hard to keep a re-infestation from happening when there are so many natural modes of travel for a nematode. The simplest way to keep a full on infestation from happening is to know the signs, test the soil on a regular basis and to treat early. Controlling nematodes is easy with MultiGuard Protect Nematicide, apply throughout the year to keep an infestation from coming back.