Incidence and distribution of head and loose smuts of sorghum (s. Bicolor l. Moench) in the Nigerian Sudan savanna
In this study, field surveys were conducted (between October to November) in the 2008 and the same period in the 2009 agricultural years to determine the incidence, prevalence and severity of head and loose smuts of sorghum in the Sudan savanna agro-ecological zone of Nigeria. The surveys were conducted in three states, namely; Kano, Katsina and Jigawa states representing the Sudan savanna region during which farmers’ fields were surveyed every 15-20 km on a road network. Disease incidence was obtained from a random sample of 100 plants each from three fields in an “X” or “W” pattern across each farm. Results of the study revealed that both head and loose smuts occurred in both years and in more than 84% of the fields surveyed. Incidence of both loose and head smuts varied significantly (P=0.05) between years and locations probably because of the variability of the pathogens and the little differences in climatic factors of the two years. The incidence of loose and head smuts in 2008 was 8.33% and 3.33%, respectively but both diseases were more prevalent and severe in Kano and Katsina states than Jigawa state. In 2009 on the other hand, head smut incidence was relatively higher averaging 5.00% compared to loose smut with mean incidence of 3.00%. However, prevalence and severity of the two diseases were still higher in Kano and Katsina states compared to jigawa state. It appeared that the incidence of the two smuts varied with the year, location and sorghum variety. The severity of the two smuts was generally low but taken together, could result into serious financial loss to farmers. So efforts should be made to find means of minimizing these losses.