About this Research Topic
Candidatus Liberibacter asiaticus is able to infect most citrus species, cultivars and hybrids. Leaves of infected trees develop a blotchy mottle symptom (yellowing vein and an asymmetrical chlorosis). Infected branches suffer substantial leaf drop, resulting in canopy thinning. Fibrous root density decreases nearly 30%, directly affecting water and nutrient uptake, with severe impact on fruit yield and demanding more often irrigation and improved nutrition. Fruit from HLB-affected trees are often lopsided, poorly colored, and contain aborted seeds, with low commercial value due to small size and quality. The juice from affected fruit present low soluble solids content, high acidity and bitterness.
There is no cure for the disease. Current management strategies focus on either delay of infection or on management of infected trees. Delay of infection methods include removal of symptomatic trees, planting with uninfected nursery trees, protection of grove edges, and intensive monitoring and pesticide control of the vector. Management of infected trees includes soil pH, nutrition, and irrigation management based on altered tree capacities and needs when affected by HLB. Research has evolved rapidly to address this devastating challenging, and several recent alternatives based on psyllid control, bactericides, cultural practices (thermotherapy and vector exclusion in young trees by protected citrus cultivation to stop contamination), and genetic transformation have been tested. While most attempts at management have focused on a single component of the disease pyramid, most do not explicitly consider multiple elements at the same time.
This Research Topic article collection aims to present the last advances in managing this pathosystem, focusing on assessments of near-term feasible practices in the context of the vector, pathogen, host plant, and environment. We also want to hear what are the prospects and potential short-term solutions to address this threat to the worldwide citrus industry.
Keywords: Huanglongbing disease, Citrus, Candidatus Liberibacter asiaticus, Infection, Disease Menagement
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