Emerging molecular knowledge on Radopholus similis, an important nematode pest of banana.

TAXONOMY: Superkingdom Eukaryota; Kingdom Metazoa; Phylum Nematoda; Class Chromadorea; Order Rhabditida; Suborder Tylenchina; Infraorder Tylenchomorpha; Superfamily Tylenchoidea; Family Pratylenchidae; Subfamily Radopholinae; Genus Radopholus. PHYSICAL PROPERTIES: Microscopic unsegmented worm; migratory endoparasite of plants. Strong sexual dimorphism; reproduction both by amphimixis and self-fertilization. HOSTS: Over 250 different plant species, including citrus, black pepper and banana (main host plant). SYMPTOMS: Purple to black lesions and extensive cavities in plant roots, leading to reduced uptake of water and nutrients. In banana, this may result in poor vegetative growth, reduced bunch weight and toppling of plants. DISEASE CONTROL: Nematicides, alternative cropping systems, nematode-free planting material, some resistant cultivars. AGRONOMIC IMPORTANCE: Major problem in banana plantations in tropical regions worldwide.