Dr. Muhammad Ashfaq. University of the Punjab, Institute of Agricultural Sciences, Lahore, Pakistan, 54590,. 0092-321-6462690;. Miss Amna Ali. University of ...
First Report of Sclerotnia Fruit Rot of Citrus paradisi Caused by Sclerotinia sclerotiorum in Pakistan apsjournals.apsnet.org /doi/abs/10.1094/PDIS-10-15-1165-PDN
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Previous Article | Next Article Accepted for publication http://dx.doi.org/10.1094/PDIS-10-15-1165-PDN Prof. Sana Hanif, MSc (Hons) Agriculture plant pathology University of the Punjab, Institute of Agricultural Sciences, Lahore, Pakistan , 54590, 923334729878; Ms. Rahila Hafeez University of the Punjab, Institute of Agricultural Sciences, Lahore, Pakistan ; Mr. Waheed Akram University of the Punjab, Institute of Agricultural Sciences, Lahore, Pakistan , 54000, 923334930639; Dr. Muhammad Ashfaq University of the Punjab, Institute of Agricultural Sciences, Lahore, Pakistan , 54590, 0092-321-6462690; Miss Amna Ali University of the Punjab, Institute of Agricultural Sciences, Lahore, Pakistan ;
PDF Print PDF with Links Grapefruit (Citrus x paradisi) has become a crop of interest in Pakistan. In November 2014, while monitoring postharvest decay of fruits during storage in Lahore city (31.32° North latitude, 74.20° East longitude), symptoms of soft watery rot with white fuzzy mycelial growth were observed on approximately 40% of ‘Duncan’ grapefruit. Dark lesions on the fruit surface containing black sclerotia were also observed. Necrotic tissues from the margin of the diseased portion of the fruit were aseptically removed and placed on PDA (potato dextrose agar) plates containing 150 µg mL-1 streptomycin sulfate. Colonies with fluffy white, broadly spreading mycelia grew to 5 cm in diameter at 20±2 ºC in 5 days. After 5 to 10 days, 1 to 7 mm diameter sclerotia appearing as black tuber-like structures were produced near the outer edge of plates. Based on morphological characteristics, the pathogen was tentatively identified as Sclerotinia sclerotiorum (Domsch et al. 1980). A single-spore isolate of the pathogen was deposited at the First Fungal Culture Bank of Pakistan (FCBP), Institute of Agricultural Sciences, University of the Punjab, Lahore Pakistan (Accession No. FCBP 1390). Identification was further confirmed by amplifying the ITS region of ribosomal DNA by using ITS4/5 primers (White et al. 1990). The resulting sequence were submitted to the Gen Bank (Accession No. KP861907). BLAST search comparisons in Gen Bank resulted in 99% homology with sequences of Sclerotinia sclerotiorum (KJ941074 and KP340898). Pathogenicity tests were performed by inoculating ‘Duncan’ grapefruit with 5-mm-diameter PDA plugs colonized by fungal mycelium (FCBP 1390) containing black sclerotia. Ten replicate fruit were inoculated with fungal plugs and another ten fruits received sterile PDA plugs as a control. The fruit were covered with transparent polyethylene bags to retain moisture and incubated at 20±2ºC. After 7 days, the aforementioned symptoms were observed on all inoculated grapefruit. No symptoms were observed on control fruits. S. sclerotiorum was re-isolated from all the inoculated fruits to complete Koch's postulates. The pathogen was identified by morphology as previously described. To our knowledge, this is the first report of postharvest fruit rot of grapefruit caused by Sclerotinia sclerotiorum in Pakistan.
