A real time PCR assay for the detection of European Stone Fruit Yellow Phytoplasma (ESFYP) in plant propagation material.

ESFY progression was noted in apricot orchards located in the province of Trento and suggested an attempt to prevent the disease spreading either by planting ESFYP-free material, cv.Bergeron and Goldrich grafted on “Wavit” or “Myrobalan 29C”, in five experimental orchards and by monitoring the presence of ESFYP-vector, the psyllid Cacopsylla pruni, as well as wild reservoirs of the phytoplasma. A real time PCR procedure for ESFYP detection was set up with a multiplex assay where host and pathogen DNA can be amplified simultaneously to distinguish between uninfected plant material and false-negative results due to PCR inhibition. Real time PCR assays were performed on: root samples from 123 individual plants, representing 15,3 % of the propagation material; groups of C. pruni (2 insects per group), collected in the vicinity of the orchards; 30 individual samples from infected (20) and healthy (10) apricots. ESFYP was detected only in all the infected apricot trees and in almost 30% of the insect groups collected in different locations. No phytoplasmas were found in the healthy plants or in the propagation material. This result suggested that newly infected trees were infected on site by vectors rather than the result of contaminated propagation material. Other research is in progress to check the presence of ESFYP-sources in wild plants in the proximity of the experimental orchards and to monitor pathogen’s dissemination.