Huanglongbing (HLB) is a devastating citrus disease that causes significant financial losses in the citrus industry. However, there is no cure by current control strategies. Damaged soils were observed in citrus orchards; root lesions and nematodes were observed in HLB-affected citrus tree roots. Bacillus subtilis (B. subtilis) makes a great contribution to pathogen control and has the potential to control HLB. Purpureocillium lilacinum (P. lilacinum) and Trichoderma harzianum (T. harzianum) can kill pathogenic organisms such as nematodes and Phytophthora spp. to protect roots. Restoration of the damaged soils and improvement of citrus root growth through the introduction of soil amendments and biocontrol agents (containing B. subtilis, P. lilacinum, and T. harzianum) may provide an efficient approach to controlling HLB. Results revealed that soil properties such as soil pH and organic matter content were improved. After three months of combination treatment of soil amendment and biocontrol agent through root drenches, the citrus grew new roots and its leaves changed from yellow to green. The percentage of HLB-positive citrus trees—Orah, Tangerine, and Navel Orange—decreased from 90 to 0%, 87.5% to 21.88%, and 81.25% to 0% over three years, respectively. Furthermore, the productivity of HLB-affected orchards was restored, and both production and quality saw significant improvement. These results suggested that combining soil remediation and biocontrol improved soil quality and protected citrus root growth, thus effectively controlling HLB.

黄龙病（HLB）是一种毁灭性的柑橘病害，给柑橘行业造成重大经济损失。然而，目前的控制策略无法治愈该病。在柑橘园中观察到土壤受损；在受 HLB 影响的柑橘树根中观察到根部病变和线虫。枯草芽孢杆菌( B.subtilis )对病原菌的控制做出了巨大贡献，具有控制HLB的潜力。紫紫霉( P.lilacinum )和哈茨木霉( T.harzianum )可以杀死线虫和疫霉属等病原微生物。以保护根部。通过引入土壤改良剂和生物防治剂（含有枯草芽孢杆菌、淡紫青霉和哈茨木霉）来恢复受损土壤并改善柑橘根系生长可能会提供一种有效的控制 HLB 的方法。结果显示，土壤pH值和有机质含量等土壤性质得到改善。经过3个月的土壤改良剂和生防剂的灌根处理，柑橘长出新根，叶子由黄变绿。三年来，HLB 阳性柑橘树（奥拉、柑橘和脐橙）的比例分别从 90% 下降到 0%，从 87.5% 下降到 21.88%，从 81.25% 下降到 0%。此外，受HLB影响的果园生产力得到恢复，产量和质量都有显着提高。这些结果表明，土壤修复和生物防治相结合可以改善土壤质量，保护柑橘根系生长，从而有效控制HLB。