First, third, and seventh authors: Department of Biological Sciences, and second, fifth, and sixth authors: Department of Natural Resources and the Environment, University of New Hampshire, Durham 03824; first and seventh authors: Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins 80523; and fourth author: NA State & Private Forestry, U.S. Department of Agriculture Forest Service, Durham, NH 03824.
Phytopathology. 2018 Mar;108(3):374-383. doi: 10.1094/PHYTO-02-17-0065-R. Epub 2018 Jan 16.
The disease complex white pine needle damage (WPND), first reported in 2006, has now escalated to an epidemic state across the northeastern United States. Although this complex is composed of several fungal species, Lecanosticta acicola is considered to be the primary causal agent. Knowledge regarding the epidemiology, specific climatic factors that affect the spread of L. acicola on eastern white pine (Pinus strobus) in natural forest settings, and potential risks repeated defoliation may have on tree health is limited. Therefore, this study examined how climatic variables affect the abundance and distance of spore dispersal of L. acicola and compared litterfall caused by defoliation versus natural needle abscission. Conidia were observed on spore traps from May through August, with a peak in abundance occurring in June, corresponding to the defoliation of second- and third-year foliage measured in litter traps. During peak spore production, relative humidity and the occurrence of rainfall was found to have the greatest influence on spore abundance. Our results will aid managers in determining how far from infected trees natural regeneration will likely be affected and predicting future disease severity based on climatic conditions.
该疾病综合症状包括白松针叶损伤（WPND），于 2006 年首次报道，目前已在美国东北部蔓延成流行病。尽管该综合症状由几种真菌物种引起，但 L. acicola 被认为是主要的致病因子。对于在自然森林环境中东部白松（Pinus strobus）上影响 L. acicola 传播的特定气候因素、生态学和反复落叶对树木健康可能产生的潜在风险的了解有限。因此，本研究检查了气候变量如何影响 L. acicola 孢子扩散的丰度和距离，并比较了落叶造成的凋落物与自然针叶脱落。从 5 月到 8 月，在孢子陷阱中观察到分生孢子，在 6 月达到丰度峰值，与在凋落物陷阱中测量的第二年和第三年叶的落叶相对应。在孢子大量产生期间，发现相对湿度和降雨的发生对孢子丰度的影响最大。我们的研究结果将有助于管理者确定自然再生可能受到感染树木多远的影响，并根据气候条件预测未来疾病的严重程度。
