2018 ASHS Annual Conference

The citrus disease Huanglongbing (HLB or citrus greening), is a bacterial disease 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, microbial induced nutrient deficiencies, 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. These changes reduced or eliminated symptoms of citrus greening, reduced or eliminated HLB rDNA titer, increased yield and quality, and, elimination of Post Bloom Fruit Drop.