Incidence and severity of fungal seedling diseases in Tamale central forest nursery, Ghana

Abstract

Fungal diseases cause serious seedling mortality in nurseries and threaten future seedling production for forest regeneration. To abate this menace, knowledge about them is key. Therefore, this study aimed at determining the incidence and severity of fungal diseases of forest seedlings in the Central Forest Nursery of Tamale, Ghana. Khaya senegalensis, Tectona grandis and Polyalthia longifolia in the nursery were infected with eight fungal pathogens and an unidentified fungus causing leaf blight, wilt, and dumping-off diseases. The pathogens included Rhizoctonia sp., Fusarium sp., Corrynespora sp., Colletotrichum sp., Cercospora sp., Phytophthora sp., Chaetomium sp., and Macrophomina sp. Rhizoctonia was the dominant pathogen isolated from all the leaves of the seedling species. Colletotrichum and Chaetomium were isolated from the leaves of Polyalthia longifolia. Cercospora and an unidentified spp. were found on the stems of Tectona grandis. Fusarium and Phytophthora were respectively found on Polyalthia longifolia and Khaya senegalensis stems. Chaetomium was identified on both Polyalthia longifolia and Khaya senegalensis stems. Cercospora and Fusarium were isolated from the roots of Tectona grandis and Polyalthia longifolia respectively while Macrophomina was associated with both Tectona grandis and Khaya senegalensis roots. Leaf blight recorded the highest disease incidence (76.7%) and affected all the three seedling species. Wilt disease showed low incidence (10.2-15.8 %) among the different seedling species. Dumping-off disease incidence (10.4%) was only recorded in Khaya senegalensis. The severities of the diseases identified were low (1-2) score except leaf blight of Tectona grandis and Polyalthia longifolia recording a moderate (3.0) severity score. It is recommended that appropriate disease management strategies be employed to prevent high incidences and severities.