Aphalara itadori is a biological control agent of the invasive Asian knotweeds Reynoutria japonica, Reynoutria sachalinensis and their hybrid Reynoutria × bohemica, which emerged across different areas of their introduced range, including Europe, North America and Oceania. The performance of A. itadori on these three target plants differs between geographically distant psyllid populations. A petition to release a population of this psyllid freshly collected in Murakami (Japan) to control the three target species in the Netherlands was approved in 2020. In order to optimize a biocontrol program using this A. itadori population, we assessed the effect of the three knotweed species on its performance, impact on plant growth and oviposition preference. The results of no-choice experiments indicated that the Murakami population performed best on R. × bohemica, where juveniles developed the fastest and the number of emerged adults was twice as high as that recorded on the other two Reynoutria hosts. These differences in performance between hosts were associated with a lower acceptance of R. sachalinensis for oviposition and a higher juvenile mortality on R. japonica. Infestation with the Murakami population had an overall negative impact on final stem length, so that infested plants were around 8 % shorter than control plants, and it reduced final rhizome fresh biomass by circa 50 % in R. sachalinensis and 35 % in R. × bohemica. When subjected to two-choice tests, females of the Murakami population did not show an oviposition preference for any of the Reynoutria species. These results suggest that in the Netherlands R. × bohemica is the best host to optimize the rearing of the Murakami population, and field releases should target this host species to promote establishment in the field. Based on these results, the Murakami population is expected to have the largest impact in the field on R. × bohemica and R. sachalinensis.