In this study, the sensitivity of 218 isolates of Colletotrichum musae to imazalil and thiabendazole was evaluated, as well the fitness and competitive ability of less sensitive isolates. There was a positive correlation between the sensitivity to the two fungicides, but the isolates were more sensitive to imazalil. The estimated effective concentration of the fungicide able to inhibit mycelial growth by 50% (EC₅₀) was used to select four isolates with the lowest and the highest values for both fungicides, which were considered as sensitive (S) and less sensitive (LS), respectively. The level of sensitivity was maintained after 10 successive transfers on fungicide‐free medium. Both fungicides were effective in controlling the disease caused by S isolates of C. musae in detached banana fruit when recommended doses were used. However, only imazalil was able to control the disease caused by LS isolates. For both fungicides, analysis of fitness‐related variables (mycelial growth, sporulation, germination, and virulence) showed no difference between the groups of S and LS isolates, but a large variation was observed within the group. The LS isolates to thiabendazole that showed a mutation (F200Y) in the β‐tubulin gene did not have fitness penalties. Our results allow a better understanding of the sensitivity and fitness of isolates of C. musae from Brazil, and demonstrate the importance of periodic monitoring to determine the frequency of LS isolates in populations, aiming at more effective management of anthracnose in banana orchards in Brazil.

中文翻译：

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对巴西炭疽菌种群的分析表明存在对采后使用的杀菌剂敏感性降低且具有高竞争能力的分离株

本研究评估了 218 株炭疽菌对抑霉唑和噻菌灵的敏感性，以及敏感性较低的菌株的适应性和竞争能力。对两种杀菌剂的敏感性呈正相关，但分离株对抑霉唑更敏感。使用能够抑制菌丝生长 50% (EC₅₀) 的杀菌剂的估计有效浓度来选择两种杀菌剂的最低和最高值的四个分离株，它们被认为是敏感的 (S) 和不太敏感的 (LS)，分别。在不含杀菌剂的培养基上连续转移 10 次后，敏感性水平得以保持。当使用推荐剂量时，这两种杀菌剂均能有效控制分离的香蕉果实中由 C. musae 分离株引起的疾病。然而，只有 imazalil 能够控制由 LS 分离株引起的疾病。对于这两种杀菌剂，对适应性相关变量（菌丝生长、孢子形成、萌发和毒力）的分析表明，S 和 LS 分离株组之间没有差异，但在组内观察到了很大的变化。显示 β-微管蛋白基因突变 (F200Y) 的噻苯达唑 LS 分离株没有适应度损失。我们的研究结果可以更好地了解来自巴西的 C. musae 分离株的敏感性和适应性，并证明了定期监测以确定种群中 LS 分离株频率的重要性，旨在更有效地管理巴西香蕉园的炭疽病。孢子形成、萌发和毒力）显示 S 和 LS 分离株组之间没有差异，但在组内观察到很大的变化。显示 β-微管蛋白基因突变 (F200Y) 的噻苯达唑 LS 分离株没有适应度损失。我们的研究结果可以更好地了解来自巴西的 C. musae 分离株的敏感性和适应性，并证明了定期监测以确定种群中 LS 分离株频率的重要性，旨在更有效地管理巴西香蕉园的炭疽病。孢子形成、萌发和毒力）显示 S 和 LS 分离株组之间没有差异，但在组内观察到很大的变化。显示 β-微管蛋白基因突变 (F200Y) 的噻苯达唑 LS 分离株没有适应度损失。我们的研究结果可以更好地了解来自巴西的 C. musae 分离株的敏感性和适应性，并证明了定期监测以确定种群中 LS 分离株频率的重要性，旨在更有效地管理巴西香蕉园的炭疽病。