Toxicity and demographic effects of fungicides on Neoseiulus longispinosus (Evans) (Acari: Phytoseiidae)

Phytoseiids are an essential group of predators that feed on phytophagous mites. Studies on the detrimental impacts of plant protection chemicals on phytoseiids are crucial for their successful utilization as biocontrol agents. In the present study, the toxicity and side effects of fungicides on the predatory mite Neoseiulus longispinosus (Evans) (Acari: Phytoseiidae) were examined fed on Tetranychus urticae Koch (Acari: Tetranychidae) in tomato under laboratory conditions. Gravid females of N. longispinosus were exposed to fungicides using the leaf dip method for 48 hours. Results showed that the fungicide metalaxyl + mancozeb caused the highest mortality of 60%, followed by mancozeb (52.50%), copper oxychloride (35%), and thiophanate methyl (17.50%). Additionally, residual toxicity from metalaxyl + mancozeb and mancozeb treatments significantly affected the biological and life table parameters of the predatory mite. However, the effects of the other two fungicides were moderate to negligible, implying that the application of metalaxyl + mancozeb and mancozeb could negatively impact the biological performance of N. longispinosus in tomato fields.