Because of its enzymes inability to break down highly lignified cell walls, this pathogen prefers to feed on younger tissues and often follows xylem vessels into developing buds and seeds. axonopodis enzymatically dissolves barriers to the plant's vascular system and so begins a systemic infection. Wounds to stems have also been noted as a means of entry. It normally enters its host plants through stomatal openings or hydathodes. manihotis is a vascular and foliar pathogenic species of bacteria. It begins as a sappy golden liquid and hardens to form an amber deposit. A further diagnostic symptom often embodies itself as pools of gum exudate along wounds and leaf cross veins. These spots begin as distinguishable moist, brown lesions normally restricted to the bottom of the plant until they enlarge and coalesce, often killing the entire leaf. axonopodis infection is angular necrotic spotting of the leaves, often with a chlorotic ring encircling the spots. A more diagnostic symptom visible in cassava with X. Symptoms include blight, wilting, dieback, and vascular necrosis. In cassava, symptoms vary in a manner that is unique to this pathogen. Consisting of about 100 species, the most economically significant species is easily the widely cultivated woody shrub, Manihot esculenta, known colloquially as the cassava plant. manihotis is capable of infecting most members of the plant genus Manihot. Among diseases which afflict cassava worldwide, bacterial blight causes the largest losses in terms of yield. Originally discovered in Brazil in 1912, the disease has followed cultivation of cassava across the world. manihotis is the pathogen that causes bacterial blight of cassava. The detailed knowledge of the epidemiology, disease development, survival and dissemination, of the reaction of cassava varieties towards CBB such as physiological resistance mechanisms, identification of genetic resistance (QTL) and the background of observed field resistance as well as of the influence of planting time and cropping pattern allows to recommend integrated management measures such as sanitation, intercropping, removal of diseased leaves, management of planting dates according to ecozone, soil amendments, use of resistant genotypes.Xanthomonas axonopodis pv. Though, comparing the development of the disease and the damages caused in yield loss trials in two agro-eco-zones over 2 years, CBB was more pronounced and caused higher yield and biomass losses in the forest savannah transition zone than in the dry savannah where symptom development was positively correlated with the rainfall patterns. In regional disease surveys across ecozones in West Africa, no zone of preference has been found. Over seasons Xam also survives often latently, in cassava stems which are then used for establishing new plantations. Also, some insects in cassava field like the variegated grasshopper (Zonocerus variegatus) vehicles the pathogen for some time. Investigating the survival period over the seasons, a longer survival exceeding 5 months has been observed in non-decayed cassava debris. In fact, Xam survives epiphytically on some weeds occurring in and around cassava fields without developing blight symptoms. manihotis (Xam), possesses several means for survival and dissemination that may play an important role as inoculum sources for the infection when favorable conditions occur, and the subsequent damage of the plant causing severe yield losses. The epidemiological and ecological investigations undertaken on the disease showed that the causal agent, the bacterium Xanthomonas axonopodis pv. Cassava (Manihot esculenta Crantz) with its long life cycle is affected by several diseases of which cassava bacterial blight (CBB) is the major bacterial disease in the cassava belt worldwide.
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