Huanglongbing (HLB) is a tritrophic disease complex involving citrus host trees, the Asian citrus psyllid (ACP) insect and a phloem restricted, bacterial pathogen Candidatus Liberibacter asiaticus (CLas). HLB is considered to be the most devastating of all citrus diseases, and there is currently no adequate control strategy. Citrusgreening.org is a database for host, vector and pathogen involved in citrus greening disease.