![]() ![]() We highlight areas that need further research attention and conclude by examining the likely future global outlook for virus disease management in cassava.Īfrica Cassava brown streak disease Cassava frogskin disease Cassava mosaic disease Host plant resistance India Pandemic Phytosanitation South America Whitefly. Components of virus control strategies examined include: diagnostics and surveillance, prevention and control of infection using phytosanitation, and control of disease through the breeding and promotion of varieties that inhibit virus replication and/or movement. Here, we review current knowledge on the biology, epidemiology, and control of the most economically important groups of viruses in relation to both farming and cultural practices. Latin America, the center of origin and domestication of the crop, hosts a diverse set of virus species, of which the most economically important give rise to cassava frog skin disease syndrome. Of major concern, causing large and increasing economic impact in Africa and Asia are the cassava mosaic geminiviruses that cause cassava mosaic disease in Africa and Asia and cassava brown streak viruses causing cassava brown streak disease in Africa. Cassava-growing continents are characterized by specific suites of viruses that affect cassava and pose particular threats. Its vegetative propagation through stem cuttings has many advantages, but deleteriously it means that pathogens are passed from one generation to the next and can easily accumulate, threatening cassava production. However, seeds usually do not show symptoms.Cassava (Manihot esculenta Crantz.) is the most important vegetatively propagated food staple in Africa and a prominent industrial crop in Latin America and Asia. Lesions can also occur on the pods causing the seeds to become shriveled and discolored. Generally young leaves are most susceptible to blight infection. manihotis) (Bredeson et al.,2016 Constantin et al. Eventually the lesions will fall out of the leaf and the foliage will appear ragged. cassava is especially vulnerable to pathogens, especially cassava bacterial blight (X. A yellowish-green "halo" will appear around the edge of water soaked tissue that surrounds the lesions. The centers of the spots will turn a dark reddish-brown and dry out. manihotis, has perhaps caused more damage globally than any other disease of cassava. Symptoms in later growth stages include angular lesions, which begin as small yellow to brown spots on the leaves. on cassava bacterial blight (CBB), African cassava mosaic disease (ACMD), biological control by local natural enemies and host plant/pest interactions, in. Bacterial blight, caused by the bacterium Xanthomonas campestris pv. ![]() Young plants may be stunted and if the infection reaches the growing point, they may die. Disease Symptomsīrown spots on the margins of the cotyledons characterize plants infected early in the growing season. Cassava bacterial blight is regarded as the major bacterial disease and limits the productivity of cassava in different major cultivation regions including South America, Asia, and Africa, where yield losses could be as high as 8090 during high epiphytotic periods (Fanou et al. Bacteria can also be spread to uninfected leaves when they rub against infected ones during cultivation, rain, and wind. 1.2.1.2.1.1 Prevalence Cassava Bacterial Blight. Seedlings may be infected through infected seed.īacteria that enter the host produce a toxin, which prevents chlorophyll production. Leaflets showing angular leaf spots and leaf blight. In order for infection to occur, the leaf surface must be wet. The bacteria enter the plants through stomata and wounds on leaves. Initial infection of soybeans occurs when wind or splashing water droplets from plant residue on the soil surface to the leaves carry bacterial cells. Bacterial blight ( Pseudomonas savastanoi) of soybeans is typically an early season disease, which over winters in the field on plant residue. ![]()
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