Simulation of the population dynamics of Diaphorina citri in citrus trees under phenological, climatic, and immigration stress

• DOI: https://doi.org/10.22533/at.ed.18136126200111

• Palavras-chave: Diaphorina citri; population dynamics; citrus

• Keywords: Diaphorina citri; population dynamics; citrus

• Abstract:

  Diaphorina citri Kuwayama is the primary vector of huanglongbing, and its temporal dynamics depend on the interaction between host budbreak, climate, and spatial connectivity. The objective of this study was to simulate the weekly population dynamics of D. citri in citrus trees under phenological, climatic, and external immigration forcing using a discrete-event model structured into eggs, nymphs, and adults. A mechanistic system was implemented in SAS with a 52-week horizon, parameterized with weekly mortalities of 0.20 for eggs and nymphs, 0.10 for adults, emigration of 0.05, and a baseline oviposition rate of 50 eggs per adult per week. The phenological signal ranged from 0.55 to 1.55, while external immigration varied between 1 and 7 adult equivalents per week. Adjusted oviposition increased from 12.60 in January to 85.25 in July. The simulation reproduced an initial establishment phase, followed by a marked acceleration starting in February and a peak expansion between June and August, when high phenology, average temperatures of 24.7–26.9 °C, and increased immigration coincided. In week 32, the population reached 2.78 × 10¹⁵ eggs, 7.56 × 10¹⁴ nymphs, and 1.11 × 10¹⁴ adults. At the end of the period, the values were 4.06 × 10²², 1.73 × 10²², and 4.41 × 10²¹, respectively. These results indicate that the synchronization between hatching, climate, and immigration decisively reorganizes the vector’s growth rate and shifts the greatest population acceleration toward the spring–summer window. The final magnitude of the trajectories reflects the system’s growth potential under favorable conditions, rather than literal local abundance, due to the absence of explicit mechanisms of demographic regulation.