Abstract: Monitoring devices based on plant volatiles are a promising tool to predict invasions of pest insects into crops or newly colonized areas. A trap baited with seven volatiles identified from a host plant has been used to forecast apple fruit moth (Argyresthia conjugella) attacks in Norwegian and Swedish apple orchards. A. conjugella is a specialized pest of rowan forest in Northern Europe, but can inflict heavy harvest losses in apple in intermasting years when rowan trees do not set adequate fruit crop and the moths invade cultivated apple orchards. Here we report the effect of several trap characteristics on the field performance of the monitoring device. To optimize the attraction of the lure, we loaded the traps with different plant volatile blends. While increasing or decreasing the complexity of the blend did not improve the catch, a significant dose-response effect was measured for the reference 7-component lure. The efficiency of the trap was not influenced by the age of the lure, which was active in the field for at least 50 days. The outside colour of the trap affected both the efficiency of the trap with regard to target pest captures and the selectivity towards non-target arthropods. These results provide a base that can be considered when developing plant volatile-based devices for pest management.