Bionomics and identification of the root-lesion nematodes Pratylenchus spp. (Nematoda: Pratylenchidae).

Root-lesion nematodes of the genus Pratylenchus are recognised worldwide as a major constraint of crops of primary economic importance, including horticultural, woody and ornamental plants. Pratylenchus species rank second only to root-knot nematodes in economic impact on crops worldwide, because of their wide host range and distribution. They are migratory endoparasites that cause severe root damage whilst feeding primarily in the cortical parenchyma. The genus Pratylenchus comprises 68 nominal species of worldwide distribution. Nevertheless, most economic damage to herbaceous, vegetables and fruit crops throughout the world is attributable to a dozen of the commonest species, including P. brachyurus in maize, cotton, peanut, pineapple, potato and tobacco; P. coffeae in coffee, citrus, sugarcane and tea; P. goodeyi in banana; P. neglectus in cereals and legumes; P. penetrans in grasses, forages, fruit trees and strawberries; P. pratensis in cereals, grasses, ornamentals and strawberries; P. scribneri in potato, soybean and strawberries; P. thornei in cereals and legumes; P. vulnus in pome and stone fruit trees, ornamentals and roses; and P. zeae which parasitizes maize, rice, sugarcane and wheat. This contribution summarises specialised information on general morphology and diagnostic traits of Pratylenchus spp. and their usefulness in taxonomy, including new biochemical and molecular diagnostic technologies. Numerous aspects of the biology, life cycle, epidemiology and ecology, pathogenicity and hostparasite relationships of Pratylenchus spp., as well as their interactions with beneficial and pathogenic fungi will be discussed.