杨树炭疽病菌对多菌灵及3种DMIs杀菌剂的敏感性
Sensitivities of poplar anthracnose fungi isolates to carbendazim and three C-14α-demethylation inhibitors

采用菌丝生长速率法，测定了可引起杨树炭疽病的59株胶孢炭疽菌和4株炭疽菌对多菌灵、苯醚甲环唑、戊唑醇和三唑酮4种杀菌剂的敏感性。结果表明：59株胶孢炭疽菌对多菌灵、苯醚甲环唑、戊唑醇和三唑酮的EC50值范围分别在0.037 1~0.130 1、0.102 5~1.680、0.069 1~1.917及3.053~38.59 μg/mL之间，平均EC50值分别为（0.066 4±0.013 1）、（0.374 1±0.254 8）、（0.681 2±0.442 1）和（19.82±6.200）μg/mL。胶孢炭疽菌对多菌灵的敏感性频率分布呈连续单峰曲线，表明尚未出现敏感性下降的群体；而对苯醚甲环唑和戊唑醇的敏感性频率分布呈现双峰，表明已出现敏感性下降的群体。4株炭疽菌对多菌灵、苯醚甲环唑、戊唑醇和三唑酮的最小EC50值和最大EC50值分别相差1.33、13.19、13.66和2.14倍，其中菌株Ca-4对苯醚甲环唑和戊唑醇的EC50值均大于4 μg/mL。不同寄主来源的胶孢炭疽菌对同种杀菌剂的敏感性之间显著差异（P>0.05）。Spearman’s秩相关分析表明，胶孢炭疽菌对苯醚甲环唑和戊唑醇的敏感性之间呈显著正相关性（ρ=0.665 5，P<0.000 1），对戊唑醇和三唑酮的敏感性之间也存在一定相关性（ρ=0.489 6，P<0.000 1），其余杀菌剂之间则均相关性（P>0.05）。研究结果对合理使用杀菌剂防治杨树炭疽病具有借鉴意义和参考价值。
Sensitivities of 59 Colletotrichum gloeosporioides isolates and four C. aenigma isolates causing poplar anthracnose to four fungicides (carbendazim, difenoconazole, tebuconazole and triadimefon) were determined by measuring the mycelium growth. The mean and the range of EC50 values of 59 C. gloeosporioides isolates were (0.066 4±0.013 1) and 0.037 1-0.130 1 μg/mL for carbendazim, (0.374 1±0.254 8) and 0.102 5-1.680 μg/mL for difenoconazole, (0.681 2±0.442 1) and 0.069 1-1.917 μg/mL for tebuconazole, and (19.82±6.200) and 3.053-38.59 μg/mL for triadimefon. The frequency distribution of EC50 values of C. gloeosporioides for carbendazim was described by continuous, unimodal curve, indicating the absence of carbendazim-resistant subpopulation among these isolates. The frequency distribution of EC50 values of C. gloeosporioides for difenoconazole and tebuconazole was bimodal curves, implying the appearance of resistant subpopulation. The highest EC50 values were 1.33-, 13.19-, 13.66-, and 2.14-times greater than the lowest values for carbendazim, difenoconazole, tebuconazole and triadimefon in the case of four C. aenigma isolates. The EC50 values of C. aenigma isolate Ca-4 to difenoconazole and tebuconazole were higher than 4 μg/mL. There was no significantly difference among the sensitivities of C. gloeosporioides isolates from different poplar hosts (P>0.05). Spearman's rank correlation analysis showed that there was positive correlation between sensitivities of C. gloeosporioides isolates for difenoconazole and tebuconazole (ρ=0.665 5, P<0.000 1), and there was weakly positive correlation between sensitivities of C. gloeosporioides isolates for tebuconazole and triadimefon (ρ=0.489 6, P<0.000 1). However, no correlation between other fungicides was observed. The results will be an important reference for chemical control of poplar anthracnose.