Studies were carried out on a striking leaf spotting observed on the leaves of rough lemon (Citrus jambhiri) plant at the permanent site of the University of Ilorin, Nigeria. Disease survey revealed that the disease was prevalent within the area of the University in the months of June-July, 2004. Symptoms begin as tiny brown spots with yellow halos on the adaxial surface of the leaf. Isolation from infected leaf materials yielded Aspergillus niger and Rhizoctonia sp. However, only Rhizoctonia sp. reproduced similar foliar lesions when artificially inoculated on healthy citrus leaves. The fungus was also re-isolated. A. niger did not elicite any disease under the conditions of this study. Rhizoctonia sp. is therefore, the causal organism of the disease under study. Keywords: Etiology, Leaf spot disease, Rough lemon, Citrus jambhiri, Aspergillus niger, Rhizoctonia sp. Bio-Research Vol. 6 (1) 2008: pp. 343-345
JE Amadi
