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This study aimed at identification and characterisation of the wilting, leaf spot, stem canker and fruit-blight diseases of okra. Pathogen infected plant samples were sterilised with 2% sodium hychlorite solution for 20 mins and then cultured at 28 °C for 15 days followed by microscopic examination. Combined microscopic, morphological and cultural characteristics analyses identified the four okra fungal isolates (OFI) such as OFI-1, OFI-2, OFI-3 and OFI-4 as Fusarium oxysporum, Curvularia lunata, Fusarium chlamydosporum and Choanephora cucurbitarum, respectively. The isolates OFI-1, OFI-2, OFI-4 showed highest radial growth rates at 25 °C, pH 5 and 20% lactose containing media while it was sucrose for OFI-3. BLASTN search using the sequence of ITS regions revealed that OFI-1, OFI-2, OFI-3 and OFI-4 isolates had 98, 100, 97 and 100% homology with F. oxysporum, C. lunata, F. chlamydosporum and C. cucurbitarum, respectively. Pathogenicity tests were also confirmed by reproducing the disease symptoms in okra plants. [ABSTRACT FROM AUTHOR]

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]