Relación entre Colletotrichum spp. y la muerte regresiva de ramas de cítricos

In citrus plantations in the south of the country associated with mechanical pruning, branch necrosis was detected in a generalized manner in the frames of trees in full production. To determine the possible causes, isolations were made from affected branches of lemon lisbon (Citrus limon) and Afourer mandarin (Citrus reticulata Blanco). Subsequently, the fungal isolates obtained were identified by morphological and molecular techniques, selecting representatives of the different morphological types observed. Pathogenicity tests were performed on detached lemon branches and flowers under controlled conditions to evaluate the relative aggressiveness of each representative and to be able to compare between them. In addition, the susceptibility of branches of different thicknesses was compared. The maximum amount of disease, the rate of symptom development and the area under the disease progress curve (AUDPC) were evaluated. From the symptoms observed in the artificial inoculations, isolations were made that confirmed the presence of the same inoculated fungi. This allowed us to comply with Koch's postulates and establish a causal relationship between Colletotrichum gloeosporioides s.s and branch necrosis in Citrus limon.