Development and reproduction of the predatory mites Kampimodromus aberrans, Typhlodromus pyri and Amblyseius andersoni on different food sources

Kampimodromus aberrans is an important predatory mite in European vineyards and fruit orchards. Pesticides can exert profound effects on K. aberrans populations that are influenced by the pesticide experience of predatory mites. Resistance to organophosphates and dithiocarbamates has been suggested for some Italian populations of K. aberrans but this phenomenon has not been shown in the laboratory. The effects of three different pesticides (chlorpyriphos-ethyl, methoxyfenozide and flufenoxuron) on K. aberrans were investigated in field and laboratory conditions. In field tests, predatory mites were released at the beginning of February on defined plots. Kampimodromus aberrans densities were evaluated on insecticide treated plots and on control plots by examining leaf samples in the laboratory from June to August. The lethal and sub-lethal effects of the same pesticides were tested in the laboratory using a residual bioassay. Field experiments showed some effects of the three pesticides on predatory mite populations. Results of bioassays were partially correlated with those obtained in the field. Implications for IPM are discussed.