Evidence of QoI fungicides resistance and fitness costs in Colletotrichum musae populations from Brazil
摘要
Anthracnose, induced by Colletotrichum musae, stands out as the paramount postharvest ailment affecting bananas. This study sought to assess Brazilian C. musae populations concerning three quinone outside inhibitor (QoI) fungicides, specifically azoxystrobin, pyraclostrobin, and trifloxystrobin, while concurrently exploring the underlying mechanisms associated with resistance. Sensitivity assays were conducted both in vitro and in vivo. A positive and significant correlation was observed between the sensitivity of C. musae isolates to different concentrations of azoxystrobin and trifloxystrobin. The estimated effective concentration of the fungicide able to inhibit mycelial growth by 50% (EC50) was used to select isolates considered as sensitive (S) and resistant (R). Despite the resistance results observed in vitro, all fungicides examined demonstrated efficacy against both S and R isolates of C. musae when employed in the treatment of detached banana fruits. Resistance stability was affirmed following ten consecutive transfers in vitro in the absence of fungicide exposure. In general, the mycelial growth rate, sporulation, germination, and virulence of R isolates was lower than that of S isolates, except for isolates resistant to pyraclostrobin, whose sporulation was significantly higher than that of S isolates. This study enables a more profound comprehension of the sensitivity to QoI fungicides and the fitness of C. musae isolates originating from Brazil.