The wool of the invasive, non-native hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), occurs mostly on hemlock (Tsuga sp.) twigs, but can be dislodged from the canopy and end up on the forest floor and tree stem underneath the canopy. Herein, we developed and tested the efficacy of two novel sampling techniques, which are based on a visual examination of the forest floor and the hemlock stem for A. tsugae wool. Subsequently, we compared these two techniques to a visual examination of foliage and ball sampling which are two methods currently used operationally. We sampled 11 hemlock stands, with low to moderate incidence A. tsugae populations, near Ithaca, New York in 2016 and assessed the probability of detecting wool on a tree and in a stand, as well as the relative variation and relative net precision for each of the four techniques. We found that sampling the tree stem outperformed foliage and ground sampling, likely because of its higher detection rate and lower relative variation, but not ball sampling. Our findings suggest that combining stem, ball and ground sampling was the most effective combination of techniques and gave a high probability of detecting an infested tree or an infested stand. All techniques were an improvement over foliage sampling, even after increasing the foliage sampling effort fivefold.

中文翻译：

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地面和茎采样作为 Adelges tsugae 羊毛的潜在检测工具（半翅目：Adelgidae）

侵入性的非本地铁杉羊毛 adelgid，Adelges tsugae Annand (Hemiptera: Adelgidae) 的羊毛主要发生在铁杉 (Tsuga sp.) 的树枝上，但可以从树冠上脱落并最终落在森林地面和树干上在天篷下面。在这里，我们开发并测试了两种新型采样技术的功效，这些技术基于对森林地面和铁杉茎的目视检查，用于 A. tsugae 羊毛。随后，我们将这两种技术与树叶和球采样的视觉检查进行了比较，这两种方法目前在操作中使用。我们于 2016 年在纽约伊萨卡附近对 11 个低至中等发病率的铁杉林进行了采样，并评估了在树上和林间检测到羊毛的概率，以及四种技术中每一种的相对变化和相对净精度。我们发现对树干进行采样优于树叶和地面采样，这可能是因为它的检测率较高且相对变化较小，但不是球采样。我们的研究结果表明，结合茎、球和地面采样是最有效的技术组合，并且很有可能检测到受侵染的树木或受侵染的林分。所有技术都是对树叶采样的改进，即使在树叶采样工作量增加了五倍之后也是如此。球和地面采样是最有效的技术组合，并且很有可能检测到受感染的树木或受感染的林分。所有技术都是对树叶采样的改进，即使在树叶采样工作量增加了五倍之后也是如此。球和地面采样是最有效的技术组合，并且很有可能检测到受感染的树木或受感染的林分。所有技术都是对树叶采样的改进，即使在树叶采样工作量增加了五倍之后也是如此。