麦水蝇Hydrellia sp.在西北地区和四川省的东北部地区为小麦上的常发性害虫。常年成虫在10—11月期间飞到小麦苗上产卵,幼虫蛀入叶鞘内为害。翌春2月下旬至3月中下旬羽化为第一代成虫;3月下旬至4月上中旬为幼虫主害时期,严重为害孕穗、抽穗期的小麦植株的上部叶鞘,4月中旬至5月上旬羽化为第二 Hydrellia sp. Is a common pest on wheat in the northwestern region and northeastern Sichuan Province. Perennial adults flew onto wheat seedlings during October-November to spawn, and larvae erode into the sheath. The next spring from late February to mid-March the emergence of the first generation of adults; late March to mid April is the period of the larvae, seriously injuring the booting, heading stage of the upper leaf sheath of wheat plants, mid April to May Emergence for the second early