Pathogenicity of fungi associated with the leaf spot disease of Eggplant (Solanum aethiopicum L.) in a derived savannah zone

Abstract

A study was carried out on the leaf spot disease of eggplant (Solanum aethiopicum L.) in Nsukka derived savannah zone. Helminthosporium infestans Butler and Jones, Cladophialophora carrionii Trejos, Aspergillus niger Them and Rapet, Rhizopus nigricans Ehhrenb and Neurospora africana Shear and Dodge were isolated from the diseased plants. Helminthsporium.infestans was the most frequently isolated organism from the infected leaves (61.11%) being glaringly higher in frequency of occurrence than A. niger (5.56%), C. carrionii (11.11%), R. nigricans (5.56%) and N. africana (16.67%). The pathogenicity tests on susceptible eggplant variety Solanum aethiopicum L. using all fungal isolated, showed that only H. infestans was pathogenic on the test crop. It produces the characteristic symptom of dark brown spots with concentric rings on the leaves, which gave target board effect on 28 days after inoculation. H. infestans was re-isolated from the infected leaves of the Eggplant. The observation of the characteristic symptom of dark yellow-brown spots with concentric rings on the leaves and re-isolation of the pathogen from infected leaves confirmed that H. infestans incited the leaf spot disease on the leaves. The other fungi also isolated may have played a synergistic role in the disease development.