Huanglongbing Pandemic: Current Challenges and Emerging Management Strategies

Abstract

Huanglongbing (HLB, aka citrus greening), one of the most devastating diseases of citrus, has wreaked havoc on the global citrus industry in recent decades. The culprit behind such a gloomy scenario is the phloem-limited bacteria “Candidatus Liberibacter asiaticus” (CLas), which are transmitted via psyllid. To date, there are no effective long-termcommercialized control measures for HLB, making it increasingly difficult to prevent the disease spread. To combat HLB effectively, introduction of multipronged management strategies towards controlling CLas population within the phloem system is deemed necessary. This article presents a comprehensive review of up-to-date scientific information about HLB, including currently available management practices and unprecedented challenges associated with the disease control. Additionally, a triangular disease management approach has been introduced targeting pathogen, host, and vector. Pathogen-targeting approaches include (i) inhibition of important proteins of CLas, (ii) use of the most efficient antimicrobial or immunity-inducing compounds to suppress the growth of CLas, and (iii) use of tools to suppress or kill the CLas. Approaches for targeting the host include (i) improvement of the host immune system, (ii) effective use of transgenic variety to build the host’s resistance against CLas, and (iii) induction of systemic acquired resistance. Strategies for targeting the vector include (i) chemical and biological control and (ii) eradication of HLB-affected trees. Finally, a hypothetical model for integrated disease management has been discussed to mitigate the HLB pandemic.

Endosymbionts of citrus leafminer Phyllocnistis citrella Stainton among different citrus orchards in China

“…The endosymbionts of insects have been reported to play a role in various aspects of insect biology, including pesticide degradation and interactions with plant pathogens 7 . In citrus pests, such as the P. citrella , understanding the endosymbionts may have implications for pest control efforts and the management of citrus diseases 8 . Research has focused on the endosymbionts of citrus psyllids (Diaphorina citri Kuwayama), which are the important carriers of Candidatus Liberibacter asiaticus, the causal agent of huanglongbing in citrus 9 – 11 .…”

Towards Huanglongbing In-field detection system with AI edge computing

“…HLB has severely affected citrus production in worldwide. Since there is no permanent cure for it, early detection and removal of infected trees are critical to preventing the spread of the disease [3] . However, labor cost to identify HLB-infected trees are rising significantly due to the expansion of citrus planting area.…”

Detection of Candidatus Liberibacter asiaticus and five viruses in individual Asian citrus psyllid in China

“…While Asian citrus psyllid (ACP) is an insect vector that transmits C Las, it is also an important factor in the prevalence of HLB ( Vyas et al., 2015 ; Snyder et al., 2022 ). At present, effective methods for the prevention and control of HLB have not been found ( Ghosh et al., 2022 ). The prevention and control of its vector, ACP, is one of the most important measures to prevent HLB epidemics.…”