Rapid detection of the pathogenic fungi causing blackleg of Brassica napus using a portable real-time fluorescence detector

•Isothermal: detection was carried on at a temperature between 37 and 42 °C.•Rapid: 1 h to obtain results from plant DNA extraction to amplification.•Simple: portable tube scanner, pipette and magnet.•Sensitivity: enough to identify real sample.•Doubleplex: simultaneous assay of aggressive L. maculans and non-aggressive species L. biglobosa.