In a two-year-study, yield loss and temporal development of incidence of Monilinia fructigena were quantified in organic apple orchards and the importance of fruit wounding agents was determined. The first infected fruits were observed at the beginning of August in 2001 and 2002. Disease development was continuous until fruit harvest in both years. Pre-harvest yield loss caused by Monilinia fructigena amounted on average 27.2% in 2001 and 41.6% in 2002 by fruit harvest. The growth rate of disease development was almost double in 2002 compared to 2001. All infected fruits were injured by wounding agents such as aboitic and mechanical injury factors, codling moth (Cydia pomonella), common earwig (Forficula auricularia) and birds. In this study, the most important wounding agents were codling moth and mechanical injury factors in organic apple orchards. In both years, our results showed that 70-80% of the infected fruits were damaged by codling moth in organic apple production. Moreover, 10-15% of the infected fruits were mechanically injured in the two years. Our results indicated that most of the damaged fruits fell on the orchard floor before harvest and they became an important secondary inoculum source of M. fructigena. Biological and practical implications of the results are discussed.