COMPARISON OF THREE DIFFERENT EVALUATION METHODS OF MONILINIA LAXA IMPACT ON APRICOT FLOWERS

D. Christen, L. Motry, G. Devènes
Brown rot blossom blight caused by Monilinia laxa is one of the main concerns for apricot cultivation, particularly for organic production. Depending on the climatic conditions, the symptoms of monilia on flowers are different. For example, the presence of spores on the flower receptacle was never observed in Switzerland. Therefore, the aim of this study was to compare different disease evaluation methods, such as weight of all infested branches, evaluation of the percentage of necrotic lesions on 5 branches or visual assessment of the disease impact on the whole tree using a scale from 1 to 4 (1=no disease, 4=tree totally infested). These methods were evaluated in order to determine the most precise and rapid one. An orchard with 43 different cultivars was artificially inoculated with mummy fruits. From the beginning of the flowering, trees were sprayed 6 times with water (1600 L/ha) in an interval of 3 days to increase the disease pressure. The most precise evaluation method was the weighing of infested branches. However, this method was highly time consuming. The second method (percentage of infected branches) was a good alternative to the first one and gave satisfactory results. However, the results have to be expressed relatively to the trunk cross section area. The third method (visual assessment) was not precise enough and a further analysis of this evaluation way revealed a good correlation with the infections on 1-year-old wood, but not on the infections on the whole tree. Such results illustrate the difficulty of evaluation of Monilia incidence on apricot and propose a reliable method for the comparison of susceptibility of different cultivars.
Christen, D., Motry, L. and Devènes, G. (2012). COMPARISON OF THREE DIFFERENT EVALUATION METHODS OF MONILINIA LAXA IMPACT ON APRICOT FLOWERS. Acta Hortic. 966, 143-147
DOI: 10.17660/ActaHortic.2012.966.22
https://doi.org/10.17660/ActaHortic.2012.966.22
Prunus armeniaca, Monilinia laxa, disease evaluation method, organic orchard
English

Acta Horticulturae