Alcune specie di nematodi, microscopici vermi tondi, si nutrono delle radici delle piante. Possono causare la formazione di un nodo caratteristico sulle radici delle piante parassitate.

• White grub worms are damaging pests of lawn grass, ornamental plants, and trees. These pests feed on the roots of host plants, causing extensive damage and reduced vigor. White grub worms are often difficult to control and most have one or two generations each year.