Yams (
Dioscorea
spp.) are food crops of growing significance in sub Saharan Africa. Unfortunately, nematodes are major pests to their production. A study was undertaken in major yam growing areas of Uganda to investigate the association of plant parasitic nematodes with damage symptoms. Nematodes were assessed from tubers, roots and surrounding soil for seven cultivars belonging to
Dioscorea alata
,
D. bulbisiana
,
D. burkilliana
and
D. cayenensis
at harvest.
Pratylenchus sudanensis
was found in the greatest density and was followed by
Meloidogyne
spp. Higher densities of both nematodes were observed in the tubers rather than roots. Although symptoms of cracking and galling were relatively low,
P. sudanensis incidence was strongly associated with cracking and
Meloidogyne spp. with galling.
Pratylenchus sudanensis and
Meloidogyne spp. incidence their associated damage were, however, negatively correlated, suggesting inter-species competition. Principal components analysis of data suggested that differences in susceptibility to
P. sudanensis occur between yam cultivars and species.