Predatory potential of Neoseiulus longispinosus (Acari: Phytoseiidae) following exposure to fungicides

The predatory potential of natural enemies plays an important role in regulating pest populations. This study evaluated the effects of four fungicides on the predatory potential of a predatory mite Neoseiulus longispinosus against Tetranychus urticae. Prey consumption began at the protonymph stage of the predatory mite and was significantly reduced under fungicidal treatments compared to the control. The lowest consumption of T. urticae eggs and protonymphs occurred in the metalaxyl + mancozeb treatment, while the highest was observed in the thiophanate methyl treatment. The predation parameters, including cumulative consumption (C₀), stable predation rate (ψ), and finite predation rate (ω), were significantly reduced in mancozeb-based treatments but remained unaffected in thiophanate methyl. Simulated projections showed that thiophanate methyl-treated predators maintained the highest prey consumption over 90 days on the log scale (log 6.47 for eggs and log 6.07 for protonymphs of T. urticae). The varying impacts of fungicides on N. longispinosus highlight the need to select fungicides compatible with predatory mites to sustain effective pest management in agroecosystems.