LAUSR

Colletotrichum isolates obtained from apple leaves with symptoms of Glomerella leaf spot (GLS) can cause fruit rot and several small lesion spots- called here as Colletotrichum fruit spot (CFS). The objective of this work was to investigate the epidemiological relevance of Colletotrichum species, obtained from leaves with GLS, on causing diseases in apple fruit, and the influence of fruit size on symptom development. For this, five Colletotrichum species were inoculated in 'Gala' (Ø = 5.5 cm) and 'Eva' (Ø = 4.8 cm) fruit in the field (2016/17 season). Subsequently, C. chrysophilum and C. nymphaeae were inoculated in different fruit sizes (Ø = 2.4-6.3 cm) in the field (2017/18 and 2021/22 seasons) and in the laboratory. At harvest of the fruit inoculated in the field, only CFS symptoms were observed in both cultivars. In these evaluations for 'Gala', the CFS incidence reached 50% regardless of season, pathogen species and fruit size. For 'Eva', CSF were observed after inoculation with C. melonis in the 2016/17 season, and in smaller fruit inoculated with C. chrysophilum and C. nymphaeae in the 2021/22. In postharvest, rot symptoms occurred, and it was not associated with the small spots. It is concluded that Gala cultivar has a high susceptibility to CFS, caused by two Colletotrichum species of greatest epidemiological importance for GLS in Brazil, in all fruit sizes tested.