ARS | Publication request: Characteristics of Monilinia fructicola isolates from decayed stone fruits in eastern West Virginia

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 6, 2010
Publication Date: July 1, 2010
Citation: Janisiewicz, W.J., Biggs, A.R. 2010. Characteristics of Monilinia fructicola isolates from decayed stone fruits in eastern West Virginia (abstract). Phytopathology. p.75.

Technical Abstract: Thirty eight isolates of Monilinia fructicola were obtained from decayed stone fruits (peach, plum, and nectarine) collected from trees growing in eleven eastern West Virginia orchards. The isolates were characterized phenotypically for growth characteristics, including: growth rate under different temperatures, sporulation, and resistance to fenbuconazole, the most commonly used preharvest fungicide in the region. There were five distinct culture phenotypes, ranging from albino to dark, melanized cultures. On PDA media, the growth rate per day of the isolates differed greatly at all temperature tested and ranged from 0.4 to 3.2 mm at 4 degrees C, from 2.9 to 7.6 mm at 10 degrees C, and from 6.5-15.5 at 24 degrees C. Sporulation on peach agar at 24 degrees C varied from profuse to no sporulation on three-day-old cultures with some cultures sporulating only sparsely even on 10-day-old cultures. In spiral dilution tests, the ED50 for fenbuconazol ranged from 0.01 ug/uL to 0.137 ug/uL, indicating the development of resistance to the fungicide in some orchards. The identity of the isolates was confirmed genetically using sequences from the ITS region of the nuclear ribosomal RNA gene repeat. In addition, a sequence of a repetitive element, 'Mona', associated with resistance of M. fructicola to DMI fungicides, was detected in the isolates.