Modeling HLB transmission and integrated control based on intercropping and vector preference

Huanglongbing (HLB), one of the most prevalent vector-borne plant diseases transmitted by psyllids, poses a devastating threat to citrus crops and has thus been dubbed “citrus cance”. In recent years, alongside the traditional HLB control measures (the removal of infected trees and pesticide application), the intercropping strategy has gradually emerged as a key focus aiming to mitigate the disease’s spread. This study develops an integrated HLB control model for citrus system, which incorporates orchard intercropping patterns and the host preference behavior of vector psyllids. We calculated the basic reproduction number ( R₀ R 0 ) and examined the existence, stability, and bifurcation phenomena of equilibrium points, including transcritical bifurcation, saddle-node bifurcation, and Hopf bifurcation. Numerical results indicate that while intercropping exerts a certain inhibitory effect on the prevention and control of HLB, it only functions as a supplementary measure within HLB’s integrated prevention and control system. Specifically, when intercropping is implemented alongside traditional control measures, an intercropping ratio of 23.1% can effectively suppress the transmission and spread of HLB. Additionally, numerical results validated the perspective of agricultural experts in Ganzhou: citrus growers need not remove all infected trees, but rather only control their proportion to below 5%.