Spatial and temporal patterns in symptom expression within eight woodlands affected by Acute Oak Decline
Spatial and temporal patterns in symptom expression within eight woodlands affected by Acute Oak Decline
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DOI：
10.1016/j.foreco.2015.10.026
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发表时间：
2016-01-15
影响因子：
3.7
通讯作者：
Denman, Sandra
中科院分区：
文献类型：
--
作者：
Brown, Nathan;Jeger, Mike;Denman, Sandra
急性橡树衰退（ACM）是英国新定义的一种疾病，在更广泛的橡树衰退复杂中形成了一个独特的组成部分。它可以通过独特的茎症状来识别，从形成层组织坏死区域渗出的深色液体从树皮板之间渗出，这与两种斑点橡树的迹象相结合。从树皮内部坏死中分离出新的细菌种类，但对AOD症状表达的时空模式知之甚少。这项研究展示了2009年至2012年间对英格兰南部和中部8个地块进行三到四年监测的结果。这些数据首次描述了AOD的流行病学。研究结果表明，受影响的树木发生在局部集群中，而不是随机分布在整个地块上，这表明是生物效应，而不是干旱等更广泛的环境效应。此外，还证实了传染（症状在邻近树木之间传播）。以前，死亡被描述为在感染后不久发生；目前的数据显示，这一阶段的时间超过两年。在2009年监测期间，有23.5%的栎树既有茎出血又有出口孔。在宿主死亡前的最后几年首次观察到出口洞，将它们与衰退的后期阶段联系起来。最后，大部分轻度感染的个体在前一年的茎症状基础上形成了愈伤组织，并进入缓解期。这一发现提示寄主的抗性可能为AOD的管理提供一些空间。Elsevier B.V.版权所有
Acute Oak Decline (ACM) is a newly defined condition in the UK that forms a distinct component within the wider oak decline complex. It can be identified by distinctive stem symptoms, dark liquid seeping out between the bark plates from areas of necrosis in the cambial tissue, which are found in conjunction with signs of the two spotted oak buprestid Agrilus biguttatus. Novel bacterial species have been isolated from the inner bark necrosis, but little is known regarding the spatial and temporal patterns of AOD symptoms expression. This study presents the results from eight plots across southern and central England monitored for three to four years between 2009 and 2012. These data give a first description of the epidemiology of AOD. Findings suggest affected trees occur in localised clusters rather than at random through the plots, pointing to biotic rather than wider scale environmental effects such as drought. In addition, contagion (spread of symptoms between neighbouring trees) was demonstrated. Previously, mortality was described as occurring soon after infection; current data suggests this is longer than two years. 23.5% of oak with both stem bleeds and exit holes in 2009 died during the monitoring period. Exit holes were observed on hosts for the first time in the final years before death linking them to the later stages of decline. Finally, a large proportion of lightly infected individuals have been shown to form callus over the previous year's stem symptoms and enter remission. This finding suggests host resistance may provide some scope for management of AOD. Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserved.