Pathogenicity and detection of Fusarium spp. causing internal fruit rot in bell pepper

Kris Van Poucke, Liesbet Van Herck, Christien Sauviller, Mario Frans, Rudi Aerts, Kurt Heungens

    Research output: Chapter in Book/Report/Conference proceedingC3: Conference Abstract


    Internal fruit rot can be a serious problem in the production of greenhouse-grown bell peppers. The disease is caused through infection of the flowers by members of the Fusarium lactis species complex (FLASC), which contains multiple sequence types (STs), and to a lesser extent by F. proliferatum and F. oxysporum. The objectives of this study were to evaluate host susceptibility in function of the Fusarium species and to determine the air load and sources of inoculum in the greenhouse.
    Fruits of four pepper cultivars were separately inoculated with FLASC ST1, FLASC ST2, FLASC ST5, FLASC ST9, F. proliferatum and F. oxysporum. In a second experiment, only FLASC ST1 was used to inoculate fruits of 5 yellow and 5 red cultivars. Lesion size was significantly larger on yellow cultivars and F. oxysporum produced the largest lesions.
    To evaluate the potential of the Fusarium species to infect flowers, two cultivars were inoculated by applying a spore suspension of FLASC ST1, FLASC ST2, FLASC ST5, F. proliferatum and F. oxysporum on the stigma. In a second experiment only FLASC ST1 was used to inoculate flowers of 10 cultivars. Fruits were sampled two weeks after inoculation and in the first experiment also at harvest. After surface sterilization, samples were placed onto PDA medium, incubated and evaluated for the presence of Fusarium. All five Fusarium species were equally able to infect flowers, but infection was dependent on the cultivar.
    It is believed that Fusarium spores spread to the stigma via air movements. We developed a molecular method to quantify spores of FLASC, F. proliferatum and F. oxysporum using sampling, DNA-extraction and specific real-time PCR assays. This method was used to monitor the air load of Fusarium spores during a growth season. In general, spores were present in high numbers during spring and became less abundant later in the year. Of the three species, FLASC spores were the most numerous. The molecular detection method was also used on samples taken from surfaces using cotton swabs. Horizontal surfaces such as the concrete pathway, plastic soil cover and rock wool substrate usually contained large numbers of spores. Also, several samples of organic residue that had dropped onto the plastic cover were tested. In many cases dried-up aborted fruits harboured a very large number of FLASC spores, indicating that they might be an important source of inoculum.
    Translated title of the contributionpathogeniciteit en detectie van Fusarium spp. die binnenrot veroorzaken bij paprika
    Original languageEnglish
    Title of host publicationabstract book 65th International Symposium on Crop Protection
    Publication date2013
    Publication statusPublished - 2013
    Event65th International Symposium on Crop Protection (2013) - Gent, Belgium
    Duration: 21-May-201321-May-2013


    • B390-crop-protection
    • B390-phytopathology

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