Losses caused by concomitant infestations of Criconemella onoensis and Helicotylenchus dihystera on upland rice in Mauritius

Abstract

In 1984, un upland rice field at the Experimental Station of the Ministry of Agriculture at Curepipe, Mauritius, showed symptoms of severe decline i.e. patches of stunted plants with etiolated leaves. Soil sampling showed the presence of Criconemella onoensis (Luc) Luc et Raski and Helicotylenchus dihystera (Cobb) Sher at mean population densities of 200 and 600 nematodes/100 ml soil, respectively; no nematodes were detected in root and stem samples. As both species have been reported to damage rice in different parts of the world (Hollis and Keoboonrueng, 1984; Prasad et al., 1987) an experiment was undertaken in 1985-86 to ascertain the losses caused to rice by these nematodes in field conditions in Mauritius.