Modelling Citrus Huanglongbing Spread in Scenarios Involving Alternative Hosts, Vector Populations and Removal of Symptomatic Plants

Abstract

Huanglongbing (HLB) is the most devastating citrus disease around the world. We have modelled HLB spread in scenarios with different populational levels of the main alternative host (Murraya paniculata) and Diaphorina citri Kuwayama (Asian citrus psyllid—ACP) vector of HLB-associated bacteria and the removal of HLB-symptomatic plants. A compartmental deterministic mathematical model was built for representing the HLB dynamics in the Recôncavo Baiano, Bahia State, Brazil. The model encompasses delays on latency and incubation disease periods and on the ACP nymphal stages. The simulations indicated that presence of alternative hosts at a low proportion would not play a crucial role in HLB dynamics in situations of poor ACP management, regardless of HLB-symptomatic plant eradication. Symptomatic citrus plants contribute more to increase the HLB incidence than the alternative host in scenarios without a suitable ACP management.