The detection of plum pox virus (PPV) was carried out in the flowers and leaves of a twelve years old infected peach tree. The presence of PPV was detected in all six branches, in flowers from the end of March to the beginning of May, and in the leaves from the beginning of May to August. PPV was easily and reliably detected in flowers from the beginning to the end of flowering, and in leaves during the May. Absorbance values (dilution of samples 1:20) varied in flower in petals from 0.30 to 1.51, in calix from 0.18 to 0.56, and in leaves from 0.29 to 0.60. The relative concentration of PPV determined by ELISA varied in flowers from 6.25 x 10(-2) to 7.81 x 10(-4) and in leaves from 3.125 x 10(-3) to 7.81 x 10(-4). The relative concentration of PPV was almost the same in flowers from the beginning to the end of flowering and the differences among branches were minimal, rather accidental. Relative concentration of PPV was two times lower in young leaves in comparison with flowers at the beginning of May. The highest concentration of PPV (7.81 x 10(-4)) in leaves showing symptoms of vein clearing was found in the middle of May. The concentration of PPV and the reliability of virus detection in leaves of peach tree was falling from June. The detection of PPV in peach trees is unreliable from August. The low value of absorbance may occur in samples diluted 1 : 20, therefore the dilution of samples 1 : 40 is recommended for detection of PPV in leaves of peach tree.
