Abstract：Citrus Huanglongbing (HLB)，the most devastating citrus disease worldwide，restricts the de-velopment of the citrus industry severely． In order to investigate the control effect of penicillin on CitrusHLB，the test was conducted by means of spraying to treat diseased trees which were infected by bacterialpathogen Candidatus Liberibacter asiaticus (Las)． The real-time fluorescence quantitative PCＲ tech-nique was used to monitor the amount of Huanglongbing pathogen in diseased trees dynamically and deter-mine the relative control effect of penicillin on Las． The results showed that the content of Las in diseasedtrees at the 3rd and 7th months after continuous spraying of penicillin 4 times was up-regulated． At thesame time，the relative control effects of the penicillin solution were － 170. 16% and － 63. 96%，re-spectively． The above results indicate that the penicillin treatment has no effect on HLB．
2019, Vol. 32 
