Potential of two omnivorous iolinid mites as predators of the tomato russet mite, Aculops lycopersici

Abstract

Two iolinid predatory mites were studied in the laboratory as potential biological control agents of the tomato russet mite, Aculops lycopersici (Acari: Eriophyidae). The development, reproduction and predation capacity of Pronematus ubiquitus and Homeopronematus anconai (Acari: Iolinidae) on A. lycopersici were investigated. Developmental time from egg to adult at 25 °C averaged 9.59, 9.31 and 9.52 days for P. ubiquitus on A. lycopersici, A. lycopersici and Typha angustifolia pollen, and pollen only, respectively. H. anconai required 11.18, 10.39 and 11.90 days to complete development on the respective diets. Survival of the immature stages exceeded 83% on all diets for both iolinids. In experimental arenas, both predators caused a substantial reduction of the immature population development of A. lycopersici. The number of tomato russet mite offspring was reduced by 78% and 57% by P. ubiquitus and H. anconai, respectively. The addition of pollen to the arena lowered this population reduction to 35% and 27% for the respective predators. However, supplementing a diet of tomato russet mites with pollen significantly increased the fecundity of both predatory mites from 14–15 to 24–25 eggs over a five-day period. The results suggest that both P. ubiquitus and H. anconai have good potential to suppress A. lycopersici populations and that T. angustifolia pollen can support population establishment of the predators. Overall, P. ubiquitus developed faster on the three diets tested and suppressed A. lycopersici stronger as compared to H. anconai, with or without pollen as a supplementary food source.