马铃薯晚疫病菌对氟吡菌胺抗性监测及9种常规药剂对马铃薯晚疫病田间防效评估

 为探明北方一季作区马铃薯晚疫病菌(Phytophthora infestans)对氟吡菌胺抗性发生动态,2012~2016年自河北、内蒙古、辽宁、吉林、黑龙江等地区采集分离到马铃薯晚疫病菌520个菌株,采用菌丝生长速率法检测供试菌株对氟吡菌胺的敏感性,并以茎叶喷雾法评价9种生产上常用药剂对马铃薯晚疫病的田间防治效果。结果表明,河北、内蒙古、辽宁、吉林、黑龙江等马铃薯一季作区晚疫病菌对氟吡菌胺敏感性趋于下降,普遍产生低水平抗性,平均抗性倍数为3.45,平均抗性指数为0.48;所有供试菌株中抗性菌株频率占90.80%,其中低抗菌株占90.35%,2016年首次检测到3株中抗菌株。2016、2017连续两年田间药效试验结果显示,按推荐剂量施药4次,687.5 g·L^-1氟吡菌胺·霜霉威盐酸盐SC对晚疫病防治效果显著高于68%精甲霜·锰锌WG、80%代森锰锌WP、250 g·L^-1嘧菌酯SC、500 g·L^-1氟啶胺SC,但2017年防效略低于2016年,由89.5%降至86.0%。氟吡菌胺的混剂687.5 g·L^-1氟吡菌胺·霜霉威盐酸盐SC仍然是目前防治晚疫病效果较好的药剂,但生产中需密切监测马铃薯晚疫病菌对氟吡菌胺的田间抗性发生动态,实施抗药性治理对策,即限制每个生长季节687.5 g·L^-1氟吡菌胺·霜霉威盐酸盐SC的施用次数,将687.5 g·L^-1氟吡菌胺·霜霉威盐酸盐SC与不同作用机理的高效内吸性杀菌剂交替使用。

Resistance monitoring of Phytophthora infestans from potato to fluopicolide and control efficacy evaluation of nine conventional fungicides against potato late blight

To clarify the development status of the resistance of Phytophthora infestans to fluopicolide in one-cropping areas, the sensitivities of 520 P. infestans strains collected from main potato production areas of Hebei Province, Inner Mongolia Autonomous Region, Liaoning province, Jilin province and Heilongjiang Pro-vince during 2012 and 2016 to fluopicolide were determined by the mycelial growth inhibition test. Also the control efficacies of 9 conventional fungicides to potato late blight were assayed in the field through spraying stems and leaves with fungicide. The results showed that the population of P. infestans tended to be less sensitive to fluopicolide and developed low resistance to fluopicolide widely all over the main potato production area of Hebei province, Inner Mongolia Autonomous Region, Liaoning Province, Jilin Province and Heilongjiang Province, with the average resistance factor and index of 3.45 and 0.48, respectively. The resistance frequency was 90.80% among all tested strains where the strains with low resistance accounted for 90.35%. Three moderate resistant strains were firstly detected in 2016. The trials of control efficacy of fungicides were performed in field in 2016 and 2017 with fungicide sprayed four times under the recommended doses. The result showed that the control efficacy of fluopicolide·propamocarb hydrochloride 687.5 g·L^-1 SC was significantly higher than mefenoxam·mancozeb 68% WG, mancozeb 80% WP, azoxystrobin 250 g·L^-1 SC and fluazinam 500 g·L^-1 SC, but the control efficacy of fluopicolide·propamocarb hydrochloride 687.5 g·L^-1 SC in 2017 (86%) was slightly lower than that in 2016 (89.5%). Above all results, the mixing formulation of flupicolide and propamocarb hydrochloride fluopicolide·propamocarb hydrochloride 687.5 g·L^-1 SC still had a high efficacy in controlling late blight currently, but it was necessary to monitor the dynamics of the resistance of P. infestans to fluopicolide, and to carry out the management strategies of resistance, including limiting the application times of fluopicolide·propamocarb hydrochloride 687.5 g·L^-1 SC within a growth season and applying fluopicolide·propamocarb hydrochloride 687.5 g·L^-1 SC in turn with other fungicides with different mechanism of action to control late blight.