Nematodes of the family Heteroderidae display a strong sexual dimorphy, in that the females are extremely swollen. Free living juveniles penetrate a plant root; they produce enzymes that dissolve the cell walls, creating space for development. When it concerns a female, she swells to such an extent that in the end she bursts out of her space, and out of the plant tissue. Then fertilization takes place; the female becomes completely filled with eggs. She then dies, the cuticle of het hardens, creating a more or less lemon-shaped, white, later brown cyst, about 1 mm long, often still more of less attached to the root. Diseased roots remain short and are strongly branched.
Although Heteroderide weaken their host plant, often seriously so, there is no damage pattern characterizing individual species. Moreover, most species have a fairly broad host plants spectre (although, whithin the species often host races do exist).