The name ‘root knot nematodes’ refers to the knots and swellings on plant roots which they cause. The scientific name Meloidogyne refers to the lemon-shaped females. Males remain slender just as the second stage juveniles which, after hatching, try to find a new host. The picture shows the head of such a juvenile.
At the anterior end a stylet is visible which is provided of three knobs or swellings to which the muscles are attached to protrude the stylet, to puncture a plant cell. The stylet is hollow. The channel or lumen in the stylet through which the food streams, continues backward in a tube; more posterior a coffee bean like structure can be observed, this structure serves as a pump.
Root not nematodes prefer (sub)tropical conditions where they cause much damage. In the Netherlands some species occur which are able to withstand lower temperatures. Meloidogyne incognita, depicted here, is restricted to glasshouses.