Suchergebnisse

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.

Stunting, poorly growing plants and poor yields, frequently observed in banana plantations during field inspections in the island of SÃO Tomé, were attributed to the decayed root systems. Laboratory examination of rhizomes, suckers and root tissues from declining plants revealed the presence of the spiral nematode Helicotylenchus multicinctus and the fungus Ceratocystis paradoxa.