Biological Aphid Control: Wasp and Gallfly Trials for *Rumex* and Foxtail Grass Management

This report details a multi-phase biological pest control project funded by the Austrian Ministry for Sustainability and Tourism, the European Union, and federal/state partnerships. It focuses on developing and testing parasitoid wasps (*Pyropteron chrysidifomis*, *P. triannulifomis*) and gallflies for controlling aphids, grassland pests, and weeds such as *Rumex* and foxtail grass. Key activities included breeding and rearing in Austria, Hungary, and Slovenia under controlled temperature conditions (≥7°C), field trials at agricultural schools and test sites in Lower Austria and Styria, and species-specific efforts targeting *Rumex* and foxtail grass. Despite challenges like weather dependency, adhesive inefficacy, and unstable rearing systems—particularly in multi-generation breeding and overwintering—some success was achieved, including 70–80% egg hatching in 2017 at Friedberg and improved hatching rates with optimized adhesives. The ragweed nettlefly project was discontinued due to insufficient baseline data. Findings were shared via a project website, newsletters, and stakeholder meetings. Recommendations emphasize stable rearing protocols, weather-independent infestation techniques, and further research into developmental thresholds and overwintering.