The most prominent problem in the current citrus industry worldwide is the epidemic of citrus Huanglongbing (HLB), also known as greening disease. In their review, Dr. Zhengqing Fu and his collaborators highlight a recent study by Huang et al. published in PNAS that identified a stable peptide with antimicrobial activities from the Australian finger lime. That peptide induces systemic immune response against HLB in Australian finger lime, effectively suppresses disease symptoms in citrus and protects healthy trees against this disease.