ABSTRACT
Several root parasitic nematodes have been shown to attack onions and more have been associated with onion roots, but there are no specific parasites of onion. Less is known about root parasites of garlic and almost nothing about those of other Allium species. The root parasitic nematodes are conveniently divided into endoparasites and ectoparasites. Lesion nematodes are the principle migratory endoparasites of onions, which can invade roots of all stages of development. Stubby root nematodes are migratory ectoparasites of roots which are consistently associated with stunted growth of onions and which make them subject to water stress. The nematode is well adapted as a parasite of leaves and crowns but can feed and invade roots. The nematodes are attracted to the cotyledon of a germinating seed and may invade it. Nematodes emigrate from infected plants into the soil, and debris from an infested crop that remains in the field is a major source of nematodes.
