Bienapfl J C, Balci Y
University of Maryland, Plant Science & Landscape Architecture, College Park 20742.
Plant Dis. 2013 Nov;97(11):1403-1407. doi: 10.1094/PDIS-03-13-0226-RE.
Pieris japonica, also known as Japanese andromeda, is an economically valuable broadleaf evergreen used in landscapes across the United States. From spring 2010 to 2012, P. japonica 'Mountain Fire' plants growing in Maryland nurseries were observed with a high incidence of stem canker, shoot dieback, and blight symptoms. Necrosis was evident on shoot tips and often advanced into lateral shoots, as well as to the crowns, leading to plant death. Phomopsis amygdali, known as a destructive pathogen of peach and almond, was consistently isolated from symptomatic plants. P. amygdali also caused similar symptoms on Mountain Fire test plants following inoculations. P. amygdali was consistently recovered and its identity was confirmed with both morphological and molecular tools, thus fulfilling Koch's postulates. In addition, nursery sampling in 2012 revealed that P. amygdali could also be isolated from asymptomatic plants. In all instances, infected plants were shipped from a West Coast nursery, indicating that this pathogen was inadvertently introduced to new locations. P. amygdali may be emerging as an important pathogen in nurseries because this is the first known association of this pathogen with an ornamental plant species.
日本杜鹃，也被称为日本马醉木，是一种具有经济价值的阔叶常绿树，在美国各地的景观中都有使用。从2010年春季到2012年，观察到马里兰州苗圃中生长的日本杜鹃‘山火’植株茎溃疡、嫩梢枯死和枯萎症状的发生率很高。嫩梢顶端出现坏死，且常常蔓延到侧枝以及树冠，导致植株死亡。扁桃叶茎点霉，一种已知的桃和杏仁的毁灭性病原菌，一直从有症状的植株中分离得到。扁桃叶茎点霉在接种后也在‘山火’试验植株上引起了类似症状。扁桃叶茎点霉一直被重新分离出来，并用形态学和分子工具确认了其身份，从而满足了柯赫氏法则。此外，2012年的苗圃采样显示，扁桃叶茎点霉也可以从无症状的植株中分离得到。在所有情况下，受感染的植株都是从西海岸的一个苗圃运来的，这表明这种病原菌是无意中被引入到新地点的。扁桃叶茎点霉可能正在成为苗圃中的一种重要病原菌，因为这是该病原菌首次与一种观赏植物物种相关联。
