2013~2015年黑龙江省马铃薯晚疫病菌群体结构研究

为明确马铃薯北方一季作区致病疫霉对烯酰吗啉和双炔酰菌胺的敏感性时空动态及常用药剂对马铃薯晚疫病的田间防效，采用菌丝生长速率法测定了2011—2019年采自河北、内蒙古和吉林3省 (区) 马铃薯主产区的922个致病疫霉菌株对烯酰吗啉和双炔酰菌胺的敏感性，采用茎叶喷雾法于2018年和2019年评估了烯酰吗啉和双炔酰菌胺等7种杀菌剂在推荐剂量下对马铃薯晚疫病的田间防效。结果表明：在时间上，不同年份采集的922株致病疫霉对烯酰吗啉的抗性频率和抗性指数分别为25.71%~100%和0.31~0.50；890株致病疫霉对双炔酰菌胺的抗性频率为0~1.43%，仅于2013年检测到抗性菌株，历年抗性指数均为0.25。在地域上，3省 (区) 致病疫霉菌株对烯酰吗啉的抗性频率和抗性指数分别为57.19%~66.56%和0.39~0.42；对双炔酰菌胺的抗性频率为0~0.36%，抗性指数均为0.25。田间药效试验结果显示：50%烯酰吗啉可湿性粉剂 (有效成分，下同) 300.0 g/hm²对马铃薯晚疫病的防治效果 (83.3%~85.6%) 高于23.4%双炔酰菌胺悬浮剂140.4 g/hm²的防治效果 (76.9%~78.6%) 和50%氟醚菌酰胺水分散粒剂75.0 g/hm²的防治效果 (70.0%~71.4%)。20%霜脲氰悬浮剂162.0 g/hm²、40%氟醚菌酰胺 • 烯酰吗啉悬浮剂240.0 g/hm²、43%霜脲氰 • 双炔酰菌胺水分散粒剂290.3 g/hm²和687.5 g/L氟吡菌胺 • 霜霉威盐酸盐悬浮剂773.4 g/hm²对马铃薯晚疫病的防治效果为79.8%~86.9%。为此，推荐烯酰吗啉单剂或混剂及双炔酰菌胺混剂在河北、内蒙古和吉林3省 (区) 继续用于马铃薯晚疫病的防治，但是需密切监测致病疫霉对烯酰吗啉和双炔酰菌胺的敏感性变化并注意与不同作用机理的杀菌剂混用或者交替使用。

Phytophthora infestans: an overview of methods and attempts to combat late blight

In order to clarify the temporal and spatial dynamics in the sensitivity of Phytophthora infestans to dimethomorph, mandipropamid, and control efficacies of the commonly used fungicides against potato late blight in one-crop potato planting regions of Northern China, the sensitivity to dimethomorph and mandipropamid in P. infestans strains collected in Hebei Province, Inner Mongolia Autonomous Region and Jilin Province from 2011 to 2019 was measured with the mycelial growth inhibition test. Also, the control efficacies of seven fungicides including dimethomorph and mandipropamid under the recommended dosages to potato late blight were assayed in the fields by spraying stems and leaves with fungicide suspensions in 2018 and 2019. The results showed the resistance frequency and resistance index of 922 P. infestans strains to dimethomorph over the years were 25.71% to 100% and 0.31 to 0.50, respectively. The resistance frequency of 890 P. infestans strains to mandipropamid over the years was 0 to 1.43% and only one resistant strain was found in 2013, and the resistance index was 0.25 for each year. The resistance frequency and resistance index of P. infestans strains in the three provinces to dimethomorph were 57.19% to 66.56% and 0.39 to 0.42, respectively. The resistance frequency of P. infestans strains in the three provinces to mandipropamid was 0 to 0.36% and the resistance index was all 0.25. The results of field efficacy trials showed the control efficacy of dimethomorph 50% WP 300.0 g a.i./hm² (83.3% to 85.6%) were higher than those of mandipropamid 23.4% SC 140.4 g a.i./hm² (76.9% to 78.6%) and fluopimomide 50% WG 75.0 g a.i./hm² (70.0% to 71.4%). The control efficacies of cymoxanil 20% SC 162.0 g a.i./hm², fluopimomide + dimethomorph 40% SC 240.0 g a.i./hm², cymoxanil + mandipropamid 43% WG 290.3 g a.i./hm², and fluopicolide + propamocarb hydrochloride 687.5 g/L SC 773.4 g a.i./hm² were 79.8% to 86.9%. Thus, dimethomorph singly or in mixtures and mandipropamid in mixtures could be used to control potato late blight in Hebei Province, Inner Mongolia Autonomous Region, and Jilin Province, but it was necessary to monitor the sensitivity dynamics of P. infestans to dimethomorph and mandipropamid, and apply fungicides containing dimethomorph or mandipropamid in mixtures or rotation with the fungicides of different action modes.