The Causal Agent of Early Blight Disease on Potato (Solanum Tuberosum L.) In North Khartoum Locality

Abstract

This is the first study undertaken to isolate and identify the causal agent of the early blight disease in potato crop in Khartoum. The laboratory investigations for identification of the causal agent were based on the culture growth, pigmentation and sporulation . conidia and conidiophores, the measurements of the conidia, color, shape, , the beak of the conidia and the presence of the spores in chains. The fungal culture was characterized by a slow to medium growth rate and conspicuous grey, dark blackish, brown or black pigmentation. The conidiopores were pale brown and the conidia was club shaped, dark brown, formed in chains with short beaks and highly septated with up to 8 transverse septa and 1-5 longitudinal septa. The length was 19-45.5 micrometer, while the width is 11.4-22.8 micrometer. It was concluded that the causal agent responsible for early blight disease in potato crop is Alternaria alternate (Fr.) K