Population Fluctuation of Predatory Mites (Acari: Phytoseiidae) in Relation to Phytophagous Mites on Apple Trees

Abstract

Predatory mites belonging to the family Phytoseiidae play an important role in the natural suppression of phytophagous mite populations in orchard ecosystems. Understanding their population dynamics in relation to prey abundance is essential for improving biological control strategies in apple production systems. The present study investigated the population fluctuation of predatory mites (Acari: Phytoseiidae) in relation to phytophagous mites on apple trees under field conditions. Periodic sampling was conducted throughout the growing season to monitor the abundance and distribution of predatory and phytophagous mite species on apple foliage. Environmental parameters including temperature, relative humidity, and seasonal variations were also evaluated to determine their influence on mite population dynamics. The results revealed significant seasonal fluctuations in both predatory and phytophagous mite populations. Population density of predatory mites increased following the rise in phytophagous mite abundance, indicating a strong predator–prey relationship within the orchard ecosystem. Peak populations of phytophagous mites were generally observed during warm and dry periods, while predatory mites responded with a delayed but substantial increase in density. Certain phytoseiid species exhibited higher adaptability and predation efficiency against dominant pest mite species on apple trees. Correlation analysis demonstrated a negative association between predatory mite abundance and phytophagous mite populations, suggesting effective natural regulation of pest outbreaks. Environmental conditions and availability of prey significantly influenced predator establishment and survival. The findings highlight the ecological importance of phytoseiid mites as biological control agents and support their conservation within integrated pest management programs aimed at reducing acaricide dependence and promoting sustainable apple orchard management.