Wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), is a major pest of wheat (Poaceae) that was first reported in the Peace River region of northwestern Alberta, Canada in 2011. Although parasitism is an important factor of mortality in wheat midge elsewhere, little is known about the prevalence, species, or distribution of wheat midge parasitoids in the Peace River region. To address this knowledge gap, we conducted a survey of wheat midge parasitoids in commercial wheat fields across the region in 2016 and 2017. For a given field, parasitism of wheat midge larvae ranged from 36 to 71%. All but one parasitoid (n = 2167) were identified as Macroglenes penetrans (Kirby) (Hymenoptera: Pteromalidae). The exception was a specimen in the genus Inostemma tentatively identified as I. walkeri Kieffer (Hymenoptera: Platygasteridae). These findings identify parasitism as an important factor that is suppressing populations of wheat midge in the Peace River region, provide the first report of Inostemma walkeri for North America, and provide the first report of this species as a parasitoid of S. mosellana.

小麦蠓，Sitodiplosis mosellana (Géhin)（双翅目：Cecidomyiidae）是一种主要的小麦（禾本科）害虫，于 2011 年在加拿大艾伯塔省西北部的和平河地区首次报道。虽然寄生是小麦死亡的一个重要因素在其他地方，对皮斯河地区小麦蠓寄生蜂的流行、种类或分布知之甚少。为了弥补这一知识差距，我们于 2016 年和 2017 年对该地区的商业麦田中的小麦蠓寄生进行了调查。对于给定的田地，麦蠓幼虫的寄生率在 36% 到 71% 之间。除了一种寄生蜂 ( n = 2167)外，其他所有寄生物都被鉴定为Macroglenes penetrans (Kirby)（膜翅目：Pteromalidae）。例外是该属中的一个标本Inostemma初步鉴定为I. walkeri Kieffer（膜翅目：Platygasteridae）。这些发现将寄生性确定为抑制和平河地区小麦蠓种群的重要因素，为北美提供了第一次关于Inostemma walkeri 的报告，并提供了该物种作为S. mosellana寄生蜂的第一次报告。