浙江省稻田稗草对二氯喹啉酸的抗药性

应用琼脂法测定了浙江省稻区21个稗草生物型对二氯喹啉酸的抗性水平。结果表明，绍兴市郊（2003年）的稗草生物型对二氯喹啉酸最敏感，其EC50为0．3268mg／L。以其为敏感生物型，绍兴陶堰（2003年）和温州塘下（2003年）的稗草生物型对二氯喹啉酸的EC50分别为234．8、227．4mg／L，抗性比分别达到718．48和695，84，表明这两种稗草生物型的抗药性处于极高抗水平。浙江杭州（2003年）的稗草生物型对二氯喹啉酸的EC50为13．47mg／L，抗性比为41．22，表明该稗草生物型处于高水平抗性阶段。绍兴皋埠（2003年）的稗草生物型对二氯喹啉酸的抗药性还处于低水平抗性阶段，其EC50和抗性比分别为2．096mg／L和6．41。而其余16个稗草生物型对二氯喹啉酸的EC50为0．4953-1.315mg／L，抗性比为1．52—4．02，表明这些地方稗草生物型对二氯喹啉酸敏感。

The resistance of barnyard grass to quinclorac in rice planting areas in Zhejiang province

The resistance level of 21 barnyard grass biotypes collected from rice planting areas in Zhejiang province were tested by agar method.The result showed the biotype collected from Shaoxing suburb in 2003 was the most susceptible barnyard grass to quinclorac,the EC50 was 0.3268 mg/L.When the biotype collected from Shaoxing suburb in 2003 as the susceptible biotype,the biotypes collected from Shaoxing Taoyan(2003)and Wenzhou Tangxia(2003)were very high resistant to quinclorac,the EC50 were 234.8 and 227.4mg/L respectively,and the resistance ratio were 718.48 and 695.84 respectively.The biotype collected from Zhejiang Hangzhou(2003)was high resistant to quinclorac,the EC50 and the resistance ratio were 13.47mg/L and 41.22 respectively.And the biotype collected from Shaoxing Gaobu(2003)was low resistant to quinclorac,the EC50 and the resistance ratio were 2.096mg/L and 6.41 respectively.However the other 16 biotypes were susceptive to quinclorac,the EC50 ranged from 0.4953mg/L to 1.315mg/L,and the resistance ratios ranged from 1.52 to 4.02.