Plant parasitic nematodes associated with plantain (Musa spp., AAB-group) in southern Nigeria and their relative importance compared to other biotic constraints

The predominant nematode species found on plantain in southern Nigeria was Helicotylenchus multicinctus which occurred at all 68 sites sampled. Hoplol aimus pararobustus. Pratylenchus coffeae and Radopholus similis were found at 64, 50 and 46% of the sites, respectively, while Meloidogyne spp. second stage juveniles were found at 68% of the sites. Other nematode species occ urred at less than 5% of the sites and included Helicotylenchus dihystera. P. zeae, P. brachyurus, Rotlylenchulus reniformis, Scutellonema and Cricone moides spp, H. multicinctus and P. coffeae occurred at high densities (on a verage about 10 500 and 3500 nematodes/100 g fresh root weight. respectivel y), compared to the other species. P. coffeae was more common in the west a nd mid-west of southern Nigeria, while R. similis was more common in the ca st. Factors, derived from a principal component analysis of observations of damage caused by nematodes, the banana weevil Cosmopolites sordidus and th e fungus Mycosphaerella fijiensis, the cause of Black Sigatoka, were relate d to plant growth observations. The results suggest that P. coffeae followe d by R. similis are the major biotic constraints of plantain production in southern Nigeria. Higher losses are anticipated by these plant parasitic ne matodes than by either M. fijienis or C. sordidus.