Development and implementation of cost-effective strategies to manage brown rot of peach trees in Imathia,Greece

Development of cost-effective strategies to manage brown rot caused by Monilinia laxa of peach implies a better understanding of the susceptibility of different cultivars and pre-harvest contamination. This study investigated the susceptibility of 24 peach and nectarine cultivars to shoot blight caused by Monilinia spp. and found various levels of susceptibility, with the nectarine cultivar Tasty Free scored as the most susceptible. Studies on the the existence and detection of latent infections by Monilinia spp. in three peach (‘A37’, ‘Andross’, and ‘E-45’) and three nectarine (‘Venus’, ‘Fantasia’, and ‘Tasty Free’) cultivars were also conducted. The results showed that latent infections were detected only in nectarine cultivars when fruit were collected on 23 May and 22 June. In contrast, nectarine fruit collected on 7 June and all peach cultivars tested had no detectable latent infection. This study also indicated that the fungicide thiophanate methyl applied at the pit hardening stage reduced significantly the percentage of latent infection and subsequently preharvest fruit rots. Finally, a disease forecast model to predict blossom blight, caused by M. laxa, was evaluated in the Prefecture of Imathia, Greece. Trees, sprayed according to the model predictions, showed a statistically lower percentage of blighted shoots than those of unsprayed trees.