Chapters authored
Fungal Diseases Occurring on Trees of Namibia
During the past few years, disease symptoms in many Acacia trees in the Windhoek Municipality area and the rest of Namibia have been observed. This observation triggered the investigation of phytopathological aspects that are reported in this chapter. The importance of indigenous trees of the Namibia flora is apparent considering that Namibia has two old deserts within its borders: the Namib Desert and the Kalahari Desert. Nambia’s tourism and meat industry are dependent on the indigenous trees of Nambia flora. The trees are the primary source of vegetation land cover (attracting tourists), and they provide browsing food matter to domestic livestock and wild animals (sources of meat). Hence, it is important to ensure that a healthy vegetation is maintained in this area.. This survey is the first dedicated step to find ways of protecting them from disease-causing agents. The aim of this survey is to investigate the possible causes of disease symptoms in trees. It is important to understand the biology of the pathogenic agents to propose a possible method to control the diseases. The survey involved sampling leaves, stems and roots from dying trees that show symptoms such as branch girdling, gum oozing and defoliation, suspicious general twig wilting and die-back. The survey was carried out in places where symptoms were observed. The tree surveys were done on Aloe zebrina, Tylosema esculentum, Syzygium and Acacia species. Primary isolations from plant material and then single-spore pure cultures were made for identification. In this chapter, we report isolation and identification of Microsphearopsis sp., Dreschelra sp., Botryosphearia spp., Acremonium spp., Coniothyrium sp., Phellinus spp., Cytospora sp., Fusarium sp., Scytalidium sp., Phoma spp., Gliomastix sp., Trichoderma koningii, Peacilomyces variotii, Alternaria citri and Curvularia palescens from the diseased trees. This work is still ongoing. This study paves way for proper designing of control methods to protect crops, trees and their biodiversity. The protection of plant biodiversity ensures better reaping of food products and other ecosystem services and products. Without knowledge of the identity of these disease-causing agents, it is not possible to accurately identify and manage threats to food production and threats to the native botanical biodiversity of Namibia.
Part of the book: Fungal Pathogenicity