First report of Colletotrichum nigrum causing tomato anthracnose in Serbia

During the survey of open tomato fields in Vojvodina (Serbia), characteristic anthracnose disease symptoms, including black, circular, sunken, and watery lesions, were observed in about 20% of fruits in September 2018. Subsequent pathogen isolations formed white aerial mycelia and numerous spherical, black conidiomata on the Potato Dextrose Agar. Ten representative isolates produced hyaline, smooth-walled, cylindrical, and aseptate conidia. The presence of initially brownish necrotic lesions on the tomato, which later expanded into large rotted areas, ultimately leading to complete fruit rot, confirmed the pathogenicity of the tested isolates. Molecular identification was performed using Bayesian analysis of concatenated ITS, TUB2, CHS-1, and ACT loci. Based on the combination of the morphological and molecular features, the fungus Colletotrichum nigrum was identified as the causal pathogen. As this is the first report on this fungal pathogen on tomatoes in Serbia, it highlights the importance of early and accurate detection for effective disease prevention, thus reducing crop damage and market losses.