![]() ![]() According to the climate model predictions, extreme weather conditions would affect the interactions between plants and pathogens and increase risks of plants infection, spatial distribution, incidence and severity of plant diseases. ![]() Disease occurrence is strongly related to the interaction between plant-pathogen-environment. These losses have been estimated to reduce global food production by 10–20%, representing a threat to food security. They are responsible for great damage and can significantly reduce crop performance and yield. Plant diseases constitute one of the major constraints to agricultural productivity. It is therefore urgent to implement control strategies such as such as the integration of new cassava varieties, screening under different agro-ecological zones and improvement of varieties in order to provide resistant varieties to the farmers. The disease was able to reach rates of 100% in many zones for both SI and DI with dieback incidence mainly in the agro-ecological 1, 4 and 6 zones under unfavourable (low rainfall, RH, NRD) and favourable conditions. The high SI and DI were found in the agro-ecological zones 1, 4 and 6. Disease expression was variable depending on the years and the prevalent weather conditions in each agro-ecological zone. The results of this study showed that the disease was present in mainly the agro-ecological zones 1, 2, 3 and 4 representing the higher yield potential zones of cassava production. Weather data were provided by weather stations in Côte d’Ivoire. These fields were assessed for the disease presence/absence, the severity index (SI) and the disease incidence (DI). Surveys were carried out in cassava fields from 2014 to 2017 in the seven Ivorian agro-ecological zones. In order to provide sustainable control strategies, it is essential to understand the occurrence and the behaviour of the disease in the different ecological zones in Côte d’Ivoire. Cassava Bacterial Blight is a particularly destructive disease influenced by weather conditions which can lead to 100% yield loss. Īnthracnose can be best controlled by using resistant cultivars.Cassava growth in Côte d’Ivoire is affected by the variation in weather conditions and various pests and diseases. Infected stems when split open show discoloration (depending on cultivar) which may be continuous over a large area, or more marbled appearance. ![]() Mid-rib infection often occurs and is seen as elongate-elliptical red or purple lesions on which the black acervuli can be clearly seen. Many lesions may develop close together and coalesce to kill large portions of the leaf. Seed treatment mentality, use of resistant cultivars and deep ploughing of fields to bury oospore inoculum are the recommended measures.Īnthracnose and Red Rot ( Colletotrichum graminicola) Where the disease is prevelant ratooning of sorghum crop is not recommended.Ībundant downy white growth (conidiophores and conidia) is produced nocturnally on the under surfaces of infected portions of leaves during humid weather. Removal of alternate host around the area will reduce initial inoculum pressure.Ī characteristic feature of the sori, which vary in length from 3 to 18 mm, is the solid long black (often curved) pointed columella which extends almost the full length of the sorus and which remains conspicuous after the smut spores have been blown away. Use of resistant cultivars and destruction of infective heads, grains is recommended. The sori or spore sacs are cylindrical, elongate, usually slightly curved with a relatively thick creamy-brown covering membrane (peridium). In the areas where the disease occurs commonly, the best practice is to plant resistant cultivars. The spores are blown away, exposing the dark filaments. The head is either completely or partially replaced by a large whitish gall. ![]()
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