Differentiation of normal and giant Vicia faba populations of the stem nematode Ditylenchus dipsaci: agreement between RAPD and phenotypic characteristics

Two important race groups of the stem nematode, Ditylenchus dipsaci, an obligatory polyphagous endoparasite, attack the bean, Vicia faba. Morphological differences have been found in the two groups and there were corresponding differences in faba bean disease symptoms. Agreement has been found between RAPD and phenotypic characteristics in the nematodes. Variation between D. dipsaci species in populations involved with V. faba was low. No strong correlation was found between geographical origin and morphological or molecular characteristics.