During the growing season 2018, samples of zucchini (Cucurbita pepo L.) fruits showing typical Fusarium rot symptoms were collected from Agadir region. Infected tissues were cut in small pieces, sterilized with 1% NaClO for 30 s, washed twice in sterile distilled water for 30 s, placed on potato dextrose agar (PDA), then incubated at 25 °C for more than 7 days. Colonies were fast growing with abundant mycelium initially white, then brown. Macroconidia had strong dorsiventral curvature, the apical cells were tapered and elongated, 5-to-7 septate, measuring 25.8–37.2 × 4.3–6.13 μm. Intercalary chlamydospores, solitary or in short chains, (4.8 to 10.1 μm), were produced on PDA after 14 days. The pathogen was identified by morphological characteristics as Fusarium sp. To confirm the species identity of this pathogen, fungal DNA was extracted (Doyle and Doyle 1990). The complete internal transcribed spacer (ITS) region of ribosomal DNA was amplified by using ITS1/ITS4 primers (White et al. 1990) and PCR amplicons of 534 bp were sequenced. The sequence (GenBank accession No. MK07283) was 98.87% identical to Fusarium equiseti (LS479419). Comparison with sequences in the FUSARIUM-ID database indicated that the pathogen was most closely related to 28 phylogenetic species within the Fusarium incarnatum –F. equiseti species complex (FIESC) with 99.04% similarity. The pathogenicity test was performed with two different methods: healthy fruits were disinfected with 70% ethanol, rinsed twice with SDW, and wounded. Fresh mycelial plugs of 0.5-cm-diameter from 7-day-old cultures or pathogen-free PDA plugs were inserted into wounds (Ravi Sankar et al. 2011). Alternatively, inoculation of wounded fruits was with 50 μl of a conidial suspension (1 × 106 conidia/ml), or SDW as negative control. Inoculated fruits were placed in a growth chamber at 25 ± 1 °C; symptoms were evaluated 7 days later. Lesions with white mycelia developed over a period of 15 days post-inoculation. The pathogen was reisolated from infected tissues, fulfilling Koch’s postulates. To our knowledge, this is the first report of F. equiseti on C. pepo in Morocco.
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Ezrari, S., Lahlali, R., Radouane, N. et al. First report of Fusarium equiseti causing pre- and postharvest fruit rot on zucchini in Morocco. J Plant Pathol 102, 251 (2020). https://doi.org/10.1007/s42161-019-00389-1
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DOI: https://doi.org/10.1007/s42161-019-00389-1