This group of organisms is highly diverse with species occupying all sorts of niches. Apart from the fact that these plant parasitic nematodes can do direct damage to the plant and can cause severe crop losses, some species are also able to transmit viral diseases. Priority diseases are Bursaphelenchus xylophilus, Globodera pallida and Globodera rostochiensis.

 Sieving method for the testing of nematodes.