First report of leaf spot on cucumber caused by Fusarium incarnatum in China.
In May 2019, a new leaf spot disease was observed on cucumber in Jiyang, Shandong Province, China. Disease incidence was estimated at approximately 15% across the survey area. Foliar symptoms began with small pale-yellow lesions, circular to irregular in shape. Subsequently, they developed into large irregular spots, yellow to dark brown, with a gray central area. Finally, the lesions were densely distributed on the leaves. To isolate and identify the pathogen, leaf tissues (5 × 5 mm) were cut from the junction of diseased tissue and healthy tissue. Based on the results of morphological observations, molecular investigations (sequence analysis of the rDNA internal transcribed spacer region, β-tubulin and partial translation elongation factor 1-α genes) and pathogenicity tests, the causal agent was identified as Fusarium incarnatum. This is thought to be the first report of leaf spot caused by F. incarnatum on cucumber in China.