Cucumber target spot, caused by Corynespora cassiicola, is a devastating fungal disease in greenhouses in China. Lack of resistant cultivars and unscientific use of fungicides aggravated the difficulty to manage this disease. In recent years, resistance of C. cassiicola to benzimidazoles, quinone outside inhibitors, and succinate dehydrogenase inhibitors has occurred in China.
In a recent study, fluazinam sensitivity distribution of 79 C. cassiicola isolates from different provinces in China based on mycelial growth inhibition was tested. The results indicated that fluazinam exhibited an excellent in vitro fungicidal activity on both mycelial growth and spore germination. It also exhibited a good in plant control efficacy on detached cucumber leaves in the protective and curative assays.
Moreover, the biological and physiological characteristics of C. cassiicola as affected by fluazinam were determined. Fluazinam not only significantly inhibited respiration and adenosine triphosphate production but also caused the increase of cell membrane permeability and the dysfunctions of cellular homeostasis.
Interestingly, there was also found that fluazinam especially damaged vacuole structures, causing the redistribution of vacuole substances. Taken together, the findings provide not only essential references for resistance management of C. cassiicola but also interesting insights for further revealing the action mode of fluazinam against plant pathogens.
Source: APS Publications.