Aggressiveness of Monilinia spp. towards detached plum fruit

Abstract

Stone fruit species are by far the most important for total fruit production in Serbia, with plum being the most important. Over the last five years, total annual plum production amounted to over 500,000 tons, placing Serbia among the three top producers in the world and the first in Europe. However, plum is severely affected by brown rot disease that occurs every year, resulting in significant losses. Monilinia laxa and Monilinia fructigena are widely distributed brown rot causal agents, with first reports of their presence and significance in Serbia originating from the middle of the 20th century. Monilinia fructicola, the most destructive pathogen of Monilinia spp., has recently been introduced into Serbia. Its spreading in stone fruit orchards has already been observed. The aim of this research was to compare aggressiveness of newly introduced M. fructicola with well-established M. laxa and M. fructigena species towards plum fruit, in order to assess the potential of M. fructicola to repress and replace the other two species in Serbian plum orchards. Unwounded and wounded fruits of two plum cultivars at three developmental stages were inoculated with M. fructicola, M. laxa, and M. fructigena. Seven days after inoculation, the fruits were visually examined for symptoms of brown rot. A CART model, describing the probability of infection establishment was constructed. The results showed that wounding of fruits, developmental stage of fruits and species of the pathogen had significant effects on the incidence of brown rot, while the effect of cultivar was not significant.