Investigation of Susceptibility of Some Apricot Cultivars to Shot-Hole (Stigmina carpophila (Lev.) M.B. Ellis) Disease Under Natural Inoculum Conditions

Abstract

Shot hole, caused by Stigmina carpophila (Lev.) M.B. Ellis, is a major fungal disease for apricots and it causes serious economic loss in Turkey. To protect apricots from the various destructive effects of the shot hole disease, excessive fungicide is used, which may lead to severe damage in ecosystem. One of the most beneficial alternative ways to minimize or eradicate hazardous effects of fungicides is to use resistant/moderately resistant varieties. This study was conducted to examine the susceptibility of 9 domestic and 10 foreign (in total 19) apricot cultivars to shot-hole disease in 2014 and 2015. The cultivars were tested under natural inoculation and no fungicide was applied in the trial. Disease symptoms were observed separately on fruits and leaves. Analysis of leaves showed that cultivars named Çağataybey (32.30%), Sakıt-7 (26.30%), and Şekerpare (25.03%) had the highest levels of disease severity while cultivars named Wilson Delicious (11.41%), Ivonne Liverani (12.54%), and Borsi Rozsa (14.35%) had the lowest levels. Findings of fruit evaluations demonstrated that the highest levels of disease severity were found on cultivars named Şekerpare (50.87%), Sakıt-7 (50.15%) and Sakıt-2 (49.85%) while the lowest levels were found on cultivars named Aprikoz (17.45%), Zard (17.69%), and Hasanbey (21.28%). Statistical analysis between leaf and fruit disease severities illustrated a moderate positive correlation. However, no statistical difference was observed between leaf and fruit disease severities in ripening periods. Disease severity levels for fruits and leaves of foreign cultivars were lower than those of domestic cultivars. Determination of disease resistances of domestic-foreign apricot cultivars with high fruit quality is thought to provide a great advantage in selecting the parents to be used as a source of resistance in breeding studies.