Leaf blight on okra caused by Choanephora cucurbitarum in China.

Okra (Abelmoschus esculentus (L.) Moench) is an economically important vegetable crop that is widely cultivated in the tropics for its nutritional properties. There are concerns, though, that in China, commercial okra production is at risk from an emerging leaf blight disease, that has been recently observed in Fujian Province. Fungi were isolated from diseased okra leaves collected in 2016 and 89 fungal isolates were tentatively identified as Choanephora cucurbitarum based on cultural and sporangia characters. DNA sequences of the internal transcribed spacer (ITS) region and the D1/D2 region of the large subunit (LSU) of the rRNA gene from two representative isolates (C6 and C7) were 99% identical to those of C. cucurbitarum obtained from NCBI. Phylogenetic analysis based on the ITS sequences showed that C6 and C7 clustered with C. cucurbitarum. All 89 fungal isolates were found to be pathogenic to okra leaves. We provide the first confirmation that, based on morphological, pathogenicity and phylogenetic analyses, the causal agent of leaf blight of okra in China was C. cucurbitarum. [ABSTRACT FROM AUTHOR]