If you have pets that come in contact with your lawn, Beneficial Nematodes are an excellent weapon to use against fleas and their larvae. These Nematodes are microscopic and live below the soil surface. They like a moist environment, so our warm wet springs are a perfect time to apply them. As flea larvae emerge, they are eaten by hungry nematodes. Nematodes do not harm worms, birds, plants or the environment, in fact they are part of the environment and are found the world over Beneficial Nematodes are sold live