Distribution and characterization of Colletotrichum species associated with Citrus anthracnose in eastern Mediterranean region of Turkey

Iminoctadine tris (albesilate)is a bis-guazatine fungicide, and its specific modes of action and efficacy against C. cassiicola are not yet clear. In this study, baseline sensitivity data for mycelial growth showed that the frequency distribution curve of iminoctadine tris (albesilate)EC50 values is unimodal. The EC50 values ranged from 0.1151 to 1.2101??g/mL, with a mean of 0.5775?±?0.2677??g/mL. Iminoctadine tris (albesilate)affected the morphological development of C. cassiicola, causing increased branching of the mycelium. The significant increase in membrane permeability and malondialdehyde content after iminoctadine tris (albesilate)treatment indicated that this fungicide caused severe damage to the membrane structure. Furthermore, 0.4??g/mL iminoctadine tris (albesilate)could decrease the spore density of C. cassiicola from 2.6200?×?104 to 1.4967?×?104/cm2 on average in vitro, indicating that the fungicide had great potential to reduce secondary infection with C. cassiicola in the field. Additionally, 120??g/mL iminoctadine tris (albesilate)provided over 95 percent curative efficacy and 81.17 percent preventative efficacy on detached cucumber leaves inoculated with C. cassiicola. In field trials, iminoctadine tris (albesilate)at a dose of 120?g a.i./ha exhibited 72.92 percent and 80.92 percent control efficacy in 2017 and 2018, respectively. However, the efficacy supplied by the reference fungicide azoxystrobin at 250?g a.i./ha was only approximately 50 percent due to the development of fungicide resistance in C. cassiicola. Taken together, the findings above provide a solid foundation for the exploration of the action mechanisms of iminoctadine tris (albesilate)against C. cassiicola and provide overwhelming evidence for the use of iminoctadine tris (albesilate)as an excellent potential alternative fungicide in the management of cucumber Corynespora leaf spot.