Diversity of fusarium oxysporum f. sp. cubense in Mozambique and associated in vitro response to fungicides, biocontrol-agents and phenolic compounds

Abstract

Panama disease or Fusarium wilt of banana is the most devastating disease of banana in the world. Fusarium oxysporum f. sp. cubense (Foc), the causative organism, has the potential to survive in soil under unfavourable conditions for over 3 decades while awaiting a potential host. This has further complicated management of Panama disease. Resistant cultivars (currently not existing for Tropical race 4 or TR4), are the only strategy that will effectively overcome the devastating impact of Panama disease. This study sought to investigate the extent of Panama disease and to identify potential management strategies for further field evaluation against Foc in Mozambique. The first epidemic of Panama disease was noticed in the mid-20 th century. Thereafter, the impacts of Panama disease have been felt where ever it occurs. Chapter 1 provides the general introduction to Panama disease and the scope of the study. It describes the existing problem, purpose and the details of the expected achievements in the study. Fusarium oxysporum f. sp. cubense and banana (the host crop) are said to have co-evolved in Asia. Chapter 2 is a review on banana and Panama disease. It also describes management measures that have been studied and applied over the years in attempt to prevent, control and eradicate Panama disease both globally and within Mozambique. Recently in 2013, the most devastating strain, Tropical race 4 (TR4) was reported in Mozambique. This was the first time TR4 has been reported in Africa ever since its first report in Asia in 1990. However, Panama disease (probable race 1 and 2) was already existent in Mozambique. Chapter 3 describes the distribution of Panama disease in Mozambique. It provides the vegetative compatibility groups (VCGs) that have been identified in the country. Host resistance is the only means through which Panama disease has been successfully managed since its catastrophic appearance in the 1950s. Various measures have been tested but have given inconsistent, short lived or poor results in the control of Panama disease. Chapter 4 looks at the effects of some biological control agents, available fungicides and phenolic compounds on Foc in vitro. It suggests the using of an integrated approach that includes Foc suppressive phenolic compounds in the management of Panama disease. The most inhibitory compounds are identified for the above regard. Chapter 5 provides the study conclusions and recommendations for further Masters Thesis: Amugoli Otuba Moses Crop Protection – Plant Pathology Page viiistudies and management of Panama disease. This study is aimed at providing a background for more studies and practices that can generate efficient measures for the management Panama disease in Mozambique