关键词: 嘧菌酯, 吡唑醚菌酯, 黄瓜残留, 消解动态, 安全使用技术

Abstract: To determine the changes in residue and environmental safety of azoxystrobin and pyraclostrobin applied on cucumber under greenhouse conditions, the residue dynamics and final residues of azoxystrobin and pyraclostrobin in cucumber was comparatively analyzed in field experiment. Meanwhile, a safe application method of the pesticides was explored to provide a guideline for application of azoxystrobin and pyraclostrobin in field, and to refine and update the residue data while helping to determine the harvest interval. The results showed that the halflives of azoxystrobin and pyraclostrobin in cucumber were 2.818-2.925 d and 2.204-2.638 d, when they were applied one time at the recommended dosage and double dosage. The final residue of pyraclostrobin and azoxystrobin were affected by the application concentration and application times, thus the residual risk was positively correlated with the application dosage and application times. The halflives of pyraclostrobin were shorter than that of azoxystrobin, which implied that pyraclostrobin in cucumber was faster degraded with lower residue at the same sampling interval period. With 2 or 3 application times of the recommended concentration for azoxystrobin and pyraclostrobins in cucumber, the postharvest interval was suggested to be 3 days, which should be appropriately extended with the raising pesticide concentration．

Key words: azoxystrobin, pyraclostrobin, cucumber residue, degradation dynamics, techniques for safe use