北美森林新病害——山毛榉叶线虫病

2012年,北美地区发生了一种由山毛榉李氏垫刃线虫麦肯恩亚种(Litylenchus crenatae mccannii)引起的森林新病害——山毛榉叶线虫病,病情蔓延迅速,已扩散至美国和加拿大30个县。病原为害山毛榉属植物,可造成病树成片死亡。由于山毛榉是北美温带阔叶林的主要构成树种和重要用材树种,新病害已引起美国农业部的高度重视并采取积极的应对措施。我国分布5种山毛榉属植物(均为特有种),是我国南方森林的主要组成树种。鉴于我国每年从北美进口大量山毛榉木材,病原线虫存在随进境木材传入国内的巨大风险。因此,检疫部门应开展风险评估,口岸应针对性开展山毛榉叶线虫病的检测。本文主要介绍了山毛榉叶线虫病的发生历史、分布范围、为害症状、病原线虫形态学特征、生活史、传播途径、分子检测方法等方面的信息,以期为口岸检疫工作提供参考。

Beech leaf disease,a new disease striking forests in North America

A new forest disease called beech leaf disease(BLD) was identified in North America in2012,then it was proved to be caused by Litylenchus crenatae mccannii many years later. BLD had spread rapidly to 30 counties in the United States and Canada since then. BLD affects and kills beech trees in North America,while beech trees are the main constituent tree species of temperate broad-leaved forests and important timber species in North America. USDA had paid more attention to BLD and had taken active countermeasures to control it. There are 5 species of beech(all endemic species) in China,which are main tree species of southern forests. In view of the fact that a large amount of beech wood is imported from North America to China every year,there is high risk of introduction of BLD into China along with imported wood. Therefore,the quarantine authority should carry out the risk assessment of BLD and the ports should perform detection specific to BLD. This paper introduced information about the history,distribution,symptoms of BLD and morphological characteristics,molecular identification,life cycle,transmission route of pathogenic nematode,in order to provide information for the quarantine of beech timber.