MELOIDOGYNE ARENARIA AND PLASMODIOPHORA BRASSICAE, CAUSAL AGENTS OF GALL DEVELOPMENT ON CABBAGE ROOTS IN THE REPUBLICA DEMOCRATICA DE SÃO TOMÉ E PRINCIPE

Abstract

An ultrastructural study of a natural infection of cabbage (Brassica oleracea) with the root-knot nematode, Meloidogyne arenaria, and the fungus, Plasmodiophora brassicae, is reported from the island of SÃO Tomé, Republica Democratica de SÃO Tomé e Principe. Histological examination of galled roots, infected by either pathogens, demonstrated that extensive gall formation was induced. Hyperplasia and hypertrophy were common phenomena in the vascular parenchyma in Meloidogyne galled roots, while extensive colonization on cortical and vascular cells with clustering of myxoamoebae around the host nuclei were constantly observed on P. brassicae infected tissues.