Survey of Resurgence of Maize Diseases in South Western and Kwara States of Nigeria

摘要

It was observed, recently, that some of the controlled diseases are resurging and causing serious yield losses on maize farms. If the diseases outbreak goes beyond economic threshold, food security of the country which maize forms a significant part may be threatened. It is necessary to have information on the type of diseases and the extent of the outbreak in the states. This survey was conducted to confirm the outbreak, evaluate the damage rate in terms of incidence and severity of resurging diseases. Forty maize farms in five states (Oyo, Osun, Ondo, Ekiti and Kwara States) were visited to survey the incidence and severity of diseases on maize. The farms were visited in the second maize planting season October to November, 2013. Farmers were interviewed and other information gathered were on the location (coordinates) of the farms, weather condition, vulnerability of the plants to diseases infection (where farms were isolated), plant growth stage, size of the farms and cultural practices. Data were collected on the incidence and severity of all the diseases found on maize in the various farms. Assessment of these diseases on the farms showed that all the maize farms visited had very high incidence (89.6%) maize streak, (65.0%) rust, (83.30%) leafspot in the season considered. The incidence and severity of maize streak was between 40-100% and 2.0-5.0 respectively across the states surveyed. Maize leaf-spot disease existed on maize in all the farms visited in all the states. The infection recorded was between 0.0 and 100.0% incidence and 0.0 and 4.0 severity. Blight disease was about 20% in the farms visited; probably because of the season. All the farmers sampled (100%) reported that the occurrence of the diseases was prominent on their farms in the second season and that the outbreaks were associated with drought conditions or irregular rains which prevailed at the season in which the survey was carried out. They are aware that improved seed varieties exist, but they do not plant improved seeds because of scarcity (30%), high cost (20%) and ignorance (50%). This survey has shown that maize streak and rust are resurging and rapidly becoming serious problem, so urgent attention is needed to prevent the great yield loss posed to maize by these diseases.