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Colletotrichum is a fungal genus comprising several pathogenic species that cause anthracnose in an array of key cash and food crops in the world's tropical, subtropical, and temperate regions. Considerable losses in various crops due to anthracnose in the African tropics have been reported despite the efforts to curb the disease. Several options are used to manage the disease in the region with little success. The challenges in managing Colletotrichum species include toxicity, high cost, inadequate farmers' knowledge of applying synthetic fungicides, variable and cross-infection nature of pathogenic species, physiological variability of pathogens, and unavailability of biological control agents to farmers in rural areas in tropical Africa. Several species of Colletotrichum are also known to develop mechanisms that allow them to counter immunity factors of the host plants. Consolidated information on the species prevalent, losses, and evaluation of the current control methods for anthracnose in the African tropics are essential for developing and adopting sustainable management strategies for anthracnose. This review discusses the key pathogenic Colletotrichum species in Africa, infection mechanisms, colonisation in several hosts, and the plant-pathogen interaction and losses due to the disease. Pathogen identification methods, disease management options, challenges, and prospects for the management of anthracnose in tropical Africa are also discussed. [ABSTRACT FROM AUTHOR]

Weevils (Sitophilus spp) are serious pests that can damage sorghum grains in stores if not controlled. The infestation of sorghum by the pest can cause huge economic loss ranging from 15% to 75% depending on levels of susceptibility. While the weevil uses several infection mechanisms such as avoidance, adaptation and sequestration to arrest its host, the host plant has developed certain chemical mechanisms for defence. The weevil must overcome the hosts’ defensive layers of chemical compounds such as protein resistant molecules, tannin, phenolics and flavonoids that confer antixenosis and or antibiosis functions in sorghum. Besides, the biochemical molecules present in sorghum are also responsible for modulating grain hardness and strength, which are important phenotypic parameters for grain resistance to weevil in sorghum. This paper reviews traits and or their associated produced chemical compounds in sorghum and reveals the gaps or need for incorporating appropriate desirable traits in sorghum through plant breeding techniques as a strategy towards management of grain weevils in sorghums. [ABSTRACT FROM AUTHOR]

Late blight disease caused by Phytophthora infestans (Mont.) de Bary is a serious challenge in tomato (Solatium fycopersicum L or Lycopersicon esculentum L) production worldwide. In tropical Africa, the disease is increasing always due to its biology and different complex infection mechanism(s) used by its causative pathogen to survive, spread, and invade the tomato host plant and environment. Management options of the disease, such as integrated disease management (IPM), use of resistant tomato varieties, use of plant extracts and synthetic chemical pesticides have been recommended but are either poorly practised or limited in tropical Africa. Thus, this review discusses the status and commonly recommended management options against late blight disease-causing pathogen(s) including the pathogen strain complexes so that tomato growers and other stakeholders can understand specific strains and how they can design appropriate managerial approaches to halt challenges of the disease in tomato production in the tropical Africa. [ABSTRACT FROM AUTHOR]