Assessing environmental risk of an exotic biocontrol agent: direct effects of Amblydromalus limonicus on the native phytoseiids Euseius finlandicus and E. stipulatus

Abstract: Amblydromalus limonicus is an exotic predatory mite routinely used for thrips control in greenhouses. Despite its occurrence on fruit trees in the places of its origin, there are still no available data reporting A. limonicus dispersal outside the greenhouse to European orchards. We herein hypothesized that A. limonicus is capable of escaping the greenhouse environment and establishing on fruit trees. For this scenario, we tested the ability of native predatory mites commonly found in European orchards to withstand competition with A. limonicus in the absence of prey. We show interspecific differences among two native predatory mites (Euseius finlandicus and E. stipulatus) in their responses to A. limonicus with E. stipulatus displaying better competitive capabilities over A. limonicus than E. finlandicus. Overall, our results imply a risk for E. finlandicus by A. limonicus in periods of prey scarcity. Research is ongoing to confirm the lab results in the field.Extended abstract