Alleviation of Huanglongbing disease in citrus by foliar application of microelements

Huanglongbing (HLB), also referred to as citrus greening disease, ranks high among the most destructive diseases in citrus plants worldwide. This disease is caused by the Gram-negative bacterium Candidatus Liberibacter species. As a strategy for the appropriate management of this disease has not been established yet, economic cultivation of citrus in the diseased areas has mostly ceased. One of the most conspicuous phenotypic characteristics of this disease is the chlorosis caused by bacterial plaques in the plant phloem systems due to microelement deficiency. Therefore, the effects of the disease may be mitigated with sufficient supply of these nutrients. This may in turn lead to the establishment of a strategy to manage the disease symptoms, even though trees might not completely recover. Such management would at least enhance the longevity of trees and contribute to an increase in their yield. Thus, an approach of reviewing microelement function might provide insights that can be translated into strategies for HLB management.