First report of Cladosporium uredinicola causing leaf spot on eggplant (Solanum melongena L.) in Iraq

Abstract

Leaf spot diseases represent a major constraint to eggplant production under favourable environmental conditions. Therefore, potential pathogenicity of the fungus Cladosporium uredinicola on the leaves of eggplant (Solanum melongena L.), cultivar 'Barcelona F1', was confirmed in this study. Symptomatic leaf tissues   were obtained from several greenhouse locations in Basrah governorate, southern Iraq. The first isolation of the fungus was done on potato dextrose agar (PDA) plates, followed by the investigation of morphological and microscopic features. Cladosporium uredinicola fungal growth on the PDA medium was olive-green to dark olivaceous-brown pigmentation and irregular margins, while the microscope conidiophores were light to medium olive colorin colour, smooth to finely roughened, bearing short terminal chains of 2–5 conidia. Pale olivaceous-brown, ellipsoid to oblong in shape, smooth-walled conidia were observed with 0–3 transverse septa. The internal transcribed spacer (ITS) region was targeted for confirming the identification; the ITS sequence was deposited in the National Center for Biotechnology Information (NCBI) GenBank database under accession number PV961371.1. Pathogenicity trials were followed under greenhouse conditions, revealing the pathogenic effect of C. uredinicola on eggplant leaves, showing necrotic lesion symptoms, which initially appeared after five days post-inoculation as small brown, circular to irregular margins, subsequently extended and coalesced into large spots and patches with chlorosis symptoms and ended with leaf abscission. The fungal pathogen was re-isolated from diseased leaves to confirm Koch's postulates. The current study represents the first report of C. uredinicola as a potential pathogen on eggplant leaves in Iraq.