Dissipation and Terminal Residue of Azoxystrobin in Lychee Under Field Conditions

We developed an effective method to determine the azoxystrobin residue in lychee And field trials were designed to evaluate the dissipation and residue of azoxystrobin in lychee at Guangzhou and Nanning.The samples were extracted by methanol and detected by GC-ECD.The results showed that the average recoveries of 83.0%-85.1%,83.3%-84.9% and 80.6% ~84.5% with relative standard deviations of 2.24%-3.88%,2.77%-3.84%and 2.90%-3.68%at the spiked level of 0.01,0.01and 1mg·kg-1.The limit of detection(LOD)was 0.005mg·kg-1 and the limit of quantification(LOQ)was 0.01 mg·kg-1.Meanwhile,the half lives of azoxystrobin in lychee of Guangzhou and Nanning were 2.8-5.7days and 3.5-7.2days,respectively,and the terminal residue were 0.01-0.16mg·kg-1,<0.01mg·kg-1 and 0.02-0.73mg·kg-1 in the whole fruit,flesh and peel at the 7days after last application,and were<0.01-0.12mg·kg-1,<0.01mg·kg-1 and 0.01-0.54 mg·kg-1 in the whole fruit,flesh and peel at the 14days after last application.Our results suggest that the terminal residue in whole fruit are all below the maximum residue limit(MRL)set by China(0.5mg·kg-1).