Population Dynamics of Panonychus citri (Acari: Tetranychidae) on Citrus and the Role of Climatic Factors

Abstract

Seasonal fluctuations of Panonychus citri (red spider mite) represent a major constraint in citrus production systems, influencing leaf photosynthetic efficiency and overall plant vigor. Field investigations were conducted to quantify population dynamics of the mite on citrus foliage and to determine the influence of key climatic variables on its abundance. Systematic sampling from orchards over multiple growth stages recorded mite incidence, density per leaf, and associated natural enemy activity. Results indicated that P. citri populations exhibited distinct seasonal peaks, with maximum abundance occurring during warm and dry periods. Correlation analysis revealed a strong positive relationship between mite density and temperature, while relative humidity and rainfall showed significant negative associations with population build-up. Regression modeling demonstrated that temperature was the most influential abiotic factor driving population increase, followed by humidity, which played a suppressive role by affecting egg hatchability and survival of immature stages. Wind speed and intermittent rainfall further contributed to mechanical dislodgement and reduced infestation intensity during monsoon periods. The study also recorded gradual population decline coinciding with increased activity of predatory mites and entomopathogenic fungal incidence under favorable humidity conditions. These findings highlight the complex interaction between climatic factors and biological regulation in shaping P. citri population trends. Understanding these dynamics is essential for forecasting pest outbreaks and optimizing integrated pest management strategies in citrus orchards. The results emphasize the importance of climate-based monitoring systems and timely intervention strategies to minimize economic losses. Overall, climatic variability plays a decisive role in regulating P. citri populations, thereby influencing long-term pest management planning in citrus agroecosystems under changing environmental conditions.