Teale Stephen A, Letkowski Steven, Matusick George, Stehman Stephen V, Castello John D
Department of Environmental and Forest Biology, College of Environmental Science and Forestry, State University of New York, Syracuse, NY 13210, USA.
Environ Entomol. 2009 Aug;38(4):1235-40. doi: 10.1603/022.038.0434.
Beech scale, Cryptococcus fagisuga Lindinger, is a non-native invasive insect associated with beech bark disease. A quantitative method of measuring viable scale density at the levels of the individual tree and localized bark patches was developed. Bark patches (10 cm(2)) were removed at 0, 1, and 2 m above the ground and at the four cardinal directions from 13 trees in northern New York and 12 trees in northern Michigan. Digital photographs of each patch were made, and the wax mass area was measured from two random 1-cm(2) subsamples on each bark patch using image analysis software. Viable scale insects were counted after removing the wax under a dissecting microscope. Separate regression analyses at the whole tree level for the New York and Michigan sites each showed a strong positive relationship of wax mass area with the number of underlying viable scale insects. The relationships for the New York and Michigan data were not significantly different from each other, and when pooling data from the two sites, there was still a significant positive relationship between wax mass area and the number of scale insects. The relationships between viable scale insects and wax mass area were different at the 0-, 1-, and 2-m sampling heights but do not seem to affect the relationship. This method does not disrupt the insect or its interactions with the host tree.
山毛榉蚧虫（Cryptococcus fagisuga Lindinger）是一种与山毛榉树皮病相关的非本地入侵昆虫。开发了一种在单株树木和局部树皮斑块水平上测量活蚧虫密度的定量方法。在纽约北部的13棵树和密歇根州北部的12棵树上，于地面以上0米、1米和2米处以及四个方位去除树皮斑块（10平方厘米）。对每个斑块拍摄数码照片，并使用图像分析软件从每个树皮斑块上两个随机的1平方厘米子样本中测量蜡质团块面积。在解剖显微镜下去除蜡质后对活蚧虫进行计数。对纽约和密歇根州地点的整株树水平分别进行的回归分析均显示，蜡质团块面积与下层活蚧虫数量之间存在很强的正相关关系。纽约和密歇根州数据的关系彼此无显著差异，并且当合并两个地点的数据时，蜡质团块面积与蚧虫数量之间仍存在显著的正相关关系。在0米、1米和2米采样高度处，活蚧虫与蜡质团块面积之间的关系有所不同，但似乎不影响这种关系。该方法不会干扰昆虫或其与寄主树的相互作用。
