Incidence and Distribution of Viruses Infecting Maize (Zea Mays L.) In South-Western Nigeria

Maize yield has greatly reduced in cultivated fields in many parts of south western Nigeria due to disease infection which has contributed immensely to the cost of production and economic loss to the farmers. A survey was conducted to investigate the incidence, distribution and severity of viral diseases on randomly selected farmer's cultivated maize field. Identification of the diseases was based on visual symptoms. Viral diseases incidence found on maize in the various farms was measured by calculating the percentage of plants showing viral disease symptoms in the maize population while the severity was assessed using a severity index scale of 1-5. Information recorded include the names of towns or villages in which survey was carried out, the coordinates of the farm (location) using the GPS (Global Positioning System), cropping system and other agronomic practices. Results were analyzed by one-way analysis of variance (ANOVA) using the statistical package for social sciences (SPSS) version 16.0. Means were separated where significant difference occur at p0.05. A simple regression analysis was used to test the effect of insect infestation on the severity of maize disease in the study area.