African Journal of
Plant Science

  • Abbreviation: Afr. J. Plant Sci.
  • Language: English
  • ISSN: 1996-0824
  • DOI: 10.5897/AJPS
  • Start Year: 2007
  • Published Articles: 728

Article in Press

Characterization Of The Causal Organisms Of Soft Rot On Tomatoes Grown In Lesotho

Mpho Liphoto, Maliehe Maqhai and Khothatso Nkhabu

  •  Received: 23 July 2020
  •  Accepted: 11 September 2020
In order to study the causal agents of tomato rot in tunnels/greenhouse, the tomato fruits (Solanum lycopersicum L) showing symptoms of soft rot were collected and their juices used for identification of microbes. Microbial isolates were obtained from lesions following surface sterilization and rinsing with distilled water. Bacteria Cultures were prepared on nutrient agar while fungal cultures were prepared on PDA (potato dextrose agar). The morphological characteristics of cultured bacteria revealed, a negative gram, white shiny colony with mucoid growth; characteristics of E. corotovora causing soft rot. Pathogenicity test on ripe tomatoes in an experiment designed as complete randomized design (CRD) with four replicates revealed, water-soaked lesions that gradually expanded. Following f-test and separation of means using least significant difference at 5%, the three different strains of E. carotovora were identified based on the diameter of the infection lesions. Fungal strains were identified as R. stolonifer based on colony morphology and pathogenicity test on ripe tomato. Colonies on potato dextrose agar at 25oC were white-cottony at first, the brownish-black sporangia with many hanging black spores grew later. The Sporangia were globose or sub-globose. The two different strains of R. stolonifer were identified based on their infection lesion size.

Keywords: Erwinia Carotovora, Rhyzopus stolonifer, Tomato (Solanum lycopersicum L), soft-rot.