越南松树枯死病症状及原因初步研究

为查明越南松树枯死的原因,对越南南部的林同省,中部的承天-顺化省,北部的广宁省的思茅松、马尾松和南亚松枯死症状和原因进行了调查,分别从枯死、濒死、健康松树木质部中抽取52份样品,用于线虫分离镜检。调查发现松树在感病后,树冠部分针叶失去光泽,逐渐褪绿变黄,进而褐红干枯,最后整个树冠变为褐色或红褐色,全株枯死,针叶下垂且当年不落;随着病程的发展,松脂分泌逐渐减少,直至停止;树干上有天牛产卵刻槽,死亡的松树上有天牛的羽化孔。在抽取的松树样品中分离鉴定到了泰国伞滑刃线虫(Bursaphelenchus thailandae BrasschBrassch-Bidasak,2002),为病原的确定和防治工作提供初步的依据。

Nematodes species survey and identification in the pine wood in Vietnam

Pine wilt desease has caused great damage to the forestry and ecological system.It became the most destructive threat to pine wood production,and it has been regarded as important inspection object.This reseach takes nematodes as materials which were atained from blasted pines in Viet Nam country,because a lot of pines were dead for unknown rea-sons in many parts of Viet Nam country.The morphological identification of the nematode were conducted.A survey of nematodes on pine wood was conducted in Viet Nam country (Lam Dong province,Thua Thien Hue province,Quang Ninh province)from september 2012 to june 2013.Collect 52 samples from 3 provinces.These samples were taken from dead,dying and exterior healthy pines.We separated and cultured nematodes gained from blasted pines;measured and calculated the numerical value of V,a,b and so on;and described modality.Parasitic nematodes on pine were also i-dentified.The results showed that one species of the genus Bursaphelenchus were identified as B.thailandae .They were i-solated from new hosts, Kesiya pine (P.kesiya R.), Massoniana pine (P.massoniana L.), Merkusii pine (P.merkusii J.),respectively.Bursaphelenchus xylophilus was not found so far in Vietnam country,while Bursaphelen-chus distributed widely in 3 provinces in Vietnam.Nematodes were isolated from 46 samples in 52 samples of pine trees.Nematode isolated ratio was 88.5%.The isolated ratio of dead,dying and healthy pine samples were 93.5%, 66.7% and 33.3% respectively.The isolated ratio of dead,dying and healthy P.kesiya samples were 96.5%,66.7%and 33.3% respectively.The isolated ratio of P.massoniana samples was 90.9%.The isolated ratio of P.merkusii samples was 83.3%.This is the first report about nematodes on pine wood distribution in Viet Nam.