Optimal control and cost-effectiveness analysis of a Huanglongbing model with comprehensive interventions

Huanglongbing (HLB) is currently one of the most devastating citrus plant diseases. To better understand the spread of HLB disease, the stage-structured compartmental model is formulated to describe the transmission dynamics of HLB between the citrus trees and Asian citrus psyllid (ACP). Based on strict mathematical derivations, the explicit expression for the basic reproduction number (R-0) of HLB is derived. The dynamics of the model are rigorously analyzed by using the theory of dynamical system. The theoretical results show that the disease-free equilibrium is globally asymptotically stable if R-0 < 1, and if R-0 > 1 the system is uniformly persistent. By applying the global sensitivity analysis of R 0, we can obtain some parameters with the most significant influence on the transmission dynamics of HLB. Moreover, the optimal control theory is used to investigate the corresponding optimal control problem of the epidemic model. Numerical simulations are conducted to reinforce the analytical results. Using the cost-effectiveness analysis, the superiority of various intervention strategies is compared by calculating Incremental Cost-Effectiveness Ratio (ICER) value. The findings imply that coupled control strategy involving insecticide spraying treatment and HLB-symptomatic trees removal is the most cost-effective strategy and belongs to long-term intervention measures, and it is recommended to take this strategy to control the disease in the whole process. On the contrary, nutrient solution treatment and yellow sticky trap control are short-term intervention measures, which can be used at the initial stage of disease outbreak but discontinued at the later stage due to cost considerations. These findings provide us potential decision-making tools that allow managers to choose better control strategies of HLB. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

The study investigates the transmission dynamics of HLB disease using a compartmental model, global sensitivity analysis, and optimal control theory. It identifies the most effective control strategy and recommends long-term intervention measures to control the disease.