Rehabilitation of Huanglongbing (Candidatus liberibacter) Infected Citrus Groves By Changes in Cultural Practices and Tree Nutrient Acquisition

Huanglongbing is a bacterial disease in citrus that is widespread throughout Florida.  Thus far, HLB has been difficult to manage due to the nonspecific disease symptoms, dissimilar environmental stresses, visible symptoms only revealed long after probable infection, differences in host - pathogen recognition and containment, and, host tolerance to the bacterium. We hypothesized citrus greening is caused by induced nutritional deficiencies enhanced by environmental stresses, and, from cultural practices; these stresses induce changes in soil microbiota, poor host nutrient acquisition and use, disruptive host metabolism, and, host immune system challenges. Cultural practices and environmental stresses may induce metabolic disorders, changes in morphology, and disease susceptibility.  When each of the stresses is addressed, metabolic disorders are corrected and morphology reverts to the norm. Program changes made to cultural practices included reduced pesticide use and rates, lower fertilizer inputs, applications of soil amendments and foliar applications of selected nutrients and inhibited metabolites. These weed control and fertilizer changes reduced or eliminated symptoms of citrus greening.