Long-term and intensive use of fungicides may lead to fungal resistance to active ingredients, even with different modes of action. In Poland, Cercospora leaf spot (CLS), the most remarkable disease of sugar beet, is mainly controlled with benzimidazoles (MBC), triazoles (DMI), and strobilurins (QoI). A constant monitoring of the emergence and the development of resistant fungal strains is required by the limited number of active ingredients. On the basis of RFLP analysis application, the aim of the study was to determine and monitor simultaneous appearing of C. beticola strains with E198A and G143A mutations. Mutation E198A in the β-tubulin gene is the main reason for MBC-resistance. Whereas mutation G143A in the cytochrome b is responsible for QoI-resistance. Most of the 414 tested C. beticola isolates (90%) were able to grow (growth inhibition percentage<50%) on the medium amended with 1 μg/ml thiophanate-methyl, and 34% of the isolates on the medium amended with 1 μg/ml azoxystrobin. Based on the PCR-RFLP analysis both mutations were detected in 44% of the tested isolates. The current study is the pioneer detection of multiple resistances to MBC and QoI fungicides in C. beticola in Poland and the European Union. The presence of multiple resistant isolates in the population of pathogens is adverse and this phenomenon requires thorough monitoring and registration of new active ingredients, allowing effective control of CLS.

长期大量使用杀菌剂可能会导致真菌对活性成分产生抗药性，即使作用方式不同。在波兰，甜菜最显着的病害尾孢菌叶斑病 (CLS)主要通过苯并咪唑 (MBC)、三唑 (DMI) 和甲氧基丙烯酸酯 (QoI) 进行防治。有限数量的活性成分需要持续监测抗性真菌菌株的出现和发展。在 RFLP 分析应用的基础上，本研究的目的是确定和监测同时出现的具有 E198A 和 G143A 突变C.β-微管蛋白基因中的突变E198A是MBC抗性的主要原因。而细胞色素b中的突变 G143A负责 QoI 抵抗。414 个测试的C. beticola分离株中的大多数（90%）能够在用 1 μg/ml 甲基托布津修正的培养基上生长（生长抑制百分比<50%），在用 1 μg/ml 嘧菌酯。基于 PCR-RFLP 分析，在 44% 的测试分离物中检测到两种突变。目前的研究是在波兰和欧盟检测到C. beticola对 MBC 和 QoI 杀菌剂的多重抗性的先驱。病原体群体中存在多种耐药分离株是不利的，这种现象需要对新的活性成分进行全面监测和登记，从而有效控制 CLS。