2009—2014年间广东省菜心炭疽病菌对咪鲜胺的敏感性

为了解广东省菜心炭疽病菌对咪鲜胺的敏感性差异和变化，于2009—2014年从广东省15个县/市菜心产区分离获得105个菜心炭疽病菌菌株，采用菌丝生长速率法测定了其对咪鲜胺的EC₅₀值，并比较了同一年份不同地区菜心炭疽病菌菌株对咪鲜胺的敏感性差异和不同年份间菜心炭疽病菌菌株对咪鲜胺的敏感性变化。结果显示:同一年份菌株间，采自2009年间的菌株对咪鲜胺的敏感性差异最小，敏感性最低地区菌株的平均EC₅₀值是最高地区菌株的1.2倍；采自2014年间的菌株对咪鲜胺的敏感性差异最大，敏感性最低地区菌株的平均EC₅₀值是最高地区菌株的34.9倍；其余年份间的不同地区最大平均EC₅₀值和最小平均EC₅₀值相差9.2~10.4倍。不同年份菌株间，2010年的菌株对咪鲜胺的敏感性最高，平均EC₅₀值为0.052 0 μg/mL；2012年的菌株对咪鲜胺的敏感性最低，平均EC₅₀值为0.259 9 μg/mL；2012—2014年的菌株对咪鲜胺的平均EC₅₀值范围在0.104 5~0.259 9 μg/mL之间，高于2009—2011年的菌株对咪鲜胺的平均EC₅₀值(0.052 0~0.074 3 μg/mL)。2009—2014年广东省田间菜心炭疽病菌菌株对咪鲜胺的敏感性呈降低趋势，存在潜在抗药性风险。

Sensitivity of Colletotrichum higginsianum isolated from Brassica parachinensis to prochloraz in Guangdong Province from 2009 to 2014

In order to evaluate the varieties and changes of the sensitivity of Colletotrichum higginsianum isolated from Brassica parachinensis to prochloraz in Guangdong Province, 105 isolates of C. higginsianum were collected from 15 counties/cities of Guangdong Province from 2009 to 2014. Their EC₅₀ values to prochloraz were determined by the mycelium growth rate method in vitro. The sensitivity of the isolates from different regions to prochloraz in the same year and the sensitivity changes of the isolates to prochloraz in different years were compared. In terms of isolates collected in the same year, the minimal sensitivity difference to prochloraz among the isolates was observed in 2009. The average EC₅₀ value of the isolates with the lowest sensitivity to prochloraz was 1.2 times higher than that of the highest sensitivity. While the greatest sensitivity difference was detected in 2014. The average EC₅₀ value of the isolates with the lowest sensitivity to prochloraz was 34.9 times higher than that of the highest sensitivity. In all the other years, the ratio between the highest average EC₅₀ value and the lowest average EC₅₀ value in different regions was 9.2 to 10.4 times. With regard to isolates collected in different years, the isolates of C. higginsianum collected in 2010 showed the highest sensitivity to prochloraz, with the average EC₅₀ value of 0.052 0 μg/mL. And the isolates collected in 2012 showed the lowest sensitivity to prochloraz, with the average EC₅₀ value of 0.259 9 μg/mL. The average EC₅₀ values of isolates collected from 2012 to 2014 ranged from 0.104 5 to 0.259 9 μg/mL, which were higher than those detected from 2009 to 2011 ranging from 0.052 0 to 0.074 3 μg/mL. From 2009 to 2014, the sensitivity of isolates of C. higginsianum in Guangdong Province showed a decreasing trend to prochloraz, which indicated potential resistance risk of C. higginsianum to prochloraz.