Detection of Ceratocystis fimbriata from soil of the plants affected with Mango Sudden Death Disease Syndrome in Pakistan.
Malik M. T., Akem C., Khan S. M., Dasti A. A., Kazmi M. R., Syed S. A., Awan M. Z., Grewal A. G., Khan M. I.
Author Affiliation: Mango Research Station, Shujabad, Pakistan.
Pakistan Journal of Phytopathology 21 : 49-54
Abstract : Mango Sudden Death Syndrome has become an important disease in Pakistan since 1997, which is closely associated with infections by Ceratocystis fimbriata possibly in concert with Botryosphaeriaceous fungi like Lasiodiplodia theobromae. Mango (Mangifera indica) trees may be affected with this disease through roots from soil borne inoculum of C. fimbriata. In Pakistan, soil borne inoculums of C. fimbriata has been recently trapped from the adjacent soil of collar portion of the diseased plants through a newly developed technique mostly resembling with immersion tube technique. The wrapped PDA culture medium in perforated aluminum foil was inserted in the soil sample and left for ten days. The contaminated agar from the holes was extracted, cut into portions and then plated on fresh PDA medium. Incubation at 25 C only for 05 days resulted in the colony growth of C. fimbriata. C. fimbriata was identified on culture morphology as mycelium hyaline, at first, later turning dark greenish-brown. Conidiophores slender arising laterally from the hyphae and producing a succession of conidia. Conidia cylindrical truncate at the ends, hyaline and smooth walled. The growth rate of culture and sub culture of soil isolates was observed comparatively quick as compared to isolates from the plant tissues of the same diseased plants. Ascospores and perithecia were also examined in the culture of the fungus isolated from the diseased plants, was a remarkable culture difference from the soil isolate. This technique was not completely species-specific but also allowed the growth of Fusarium sp and some nematodes as well. Further, fast growing contaminants such as Fusarium and Penicillium from the same soil sample were also baited using carrot slices and mango twigs stripped of their bark partially. Surely, this ever first detection of Ceratocystis fimbriata from soil will help to understand the epidemiology i.e. survival of pathogen, its means of movement and dispersal in mango orchards of Pakistan.