北海道における侵入害虫アシグロハモグリバエの発生確認後10年間の分布拡大

抄録

In Hokkaido, the northern island of Japan, an introduced pest, Liriomyza huidobrensis, was discovered infesting spinach and chrysanthemum in greenhouses in the eastern area of the Iburi district in 2001. This was the first record of the pest in Japan. During the following ten years, its distribution has spread throughout Hokkaido yearly. By autumn of 2010, it was found in 43 towns, throughout a wide area of Hokkaido. Of these 43 towns, 31 were in neighboring towns of the town where it has already been recorded. In addition, the dispersal of the pest in rice paddy areas seemed to be inactive, maybe owing to the fewer opportunities of immigrant flies for landing on suitable places/host plants. These findings suggest that L. huidobrensis naturally dispersed to adjacent areas in the majority of cases. On the other hand, there have been several cases in which the pest was discovered in places far from hitherto known areas where the pest occurs. This may be due to an artificial movement of plants infested by the pest.