Abstract：
Hemlock woolly adelgid (HWA), Adelges tsugae Annand, is a major forest pest in the eastern United States responsible for killing millions of eastern hemlock, Tsuga canadensis (L.) Carrière and Carolina hemlock, T. caroliniana Engelmann. The US biological control program for HWA has largely invested in the rearing and release of Laricobius nigrinus Fender and more recently L. osakensis Montgomery and Shiyake. Though the establishment of L. nigrinus has been well-documented in the southern, mid-Atlantic, and coastal portions of the northeastern United States, documentation in interior areas of the northeastern United States is limited. Establishment of L. osakensis in the northeastern United States has not yet been documented. Release locations in the northeastern United States were surveyed for L. nigrinus and L. osakensis establishment to examine the relationship between establishment success and winter temperatures, as winter minimum temperatures likely limit the northern range of introduced Laricobius species. Our results suggest that L. nigrinus establishment is limited by winter minimum temperatures and that the probability of establishment declines as absolute minimum temperature declines. We found L. nigrinus established at sites in Maine, New York, and Pennsylvania, but did not recover any L. nigrinus in Massachusetts, New Hampshire, or Vermont. Similarly, we found L. osakensis established at sites in New York and Pennsylvania and recovered individuals in Maine, though further sampling is necessary to confirm presence of the F3 generation. We also report the first field observation of reproduction of silver flies, Leucotaraxis argenticollis (Diptera: Chamaemyiidae), released predator of HWA, in the eastern United States.
摘要：
Hemlock羊毛adelgid（HWA），AdelgestusgaeAnnand,是美国东部的主要森林害虫，杀死了数百万的东部铁杉，Tsugacanadensis（L.)卡里埃和卡罗来纳州铁杉，T.CarolinianaEngelmann.美国对HWA的生物防治计划已在很大程度上投资了NigrinusFender和最近的L.osakensisMontgomery和Shiyake的饲养和释放。尽管在南部已经有很好的记录，大西洋中部,和美国东北部的沿海地区，美国东北部内陆地区的文件有限。尚未在美国东北部建立L.osakensis。对美国东北部的释放地点进行了调查，以检查建立成功与冬季温度之间的关系，因为冬季最低温度可能会限制引入的Laricobius物种的北部范围。我们的结果表明，黑草的建立受到冬季最低温度的限制，并且建立的可能性随着绝对最低温度的下降而下降。我们发现L.nigrinus在缅因州的一些地方建立，纽约,宾夕法尼亚州,但在马萨诸塞州没有发现任何黑草，新罕布什尔州,或者佛蒙特州.同样，我们发现了在纽约和宾夕法尼亚州的地点建立的L.osakensis，并在缅因州恢复了个体，尽管需要进一步采样以确认F3代的存在。我们还报告了银蝇繁殖的第一次现场观察，白术后叶翅目（双翅目：Chamaemyiidae），释放了HWA的捕食者，在美国东部。
