A nematicide is a type of chemical pesticide used to kill parasitic nematodes (roundworms). One common nematicide is obtained from neem cake, the residue obtained after cold-pressing the fruit and kernels of the neem tree. Known by several names in the world, the tree was first cultivated in India since ancient times and is now widely distributed throughout the world. Nematophagous fungi, a type of carnivorous fungi, can be useful in controlling nematodes, Paecilomyces being one example.

Prior to 1985, the persistent halocarbon DBCP was a widely used nematicide and soil fumigant. However, it was banned from use after being linked to sterility among male workers; the Dow Chemical company was subsequently found liable for more than $600 million in damages.