湖北三峡地区松材线虫的耐寒性

为了探究松材线虫的耐寒性,以采自湖北省宜昌市夷陵区的松材线虫（ Bursaphelenchus xylophilus）为试验对象,研究低温及低温驯化对松材线虫存活情况的影响。结果表明：松材线虫有较强的耐低温能力,在10、5、0、－5、－10℃低温条件下,随着处理时间的延长,松材线虫存活率逐渐降低,各温度半致死时间分别为20．17、35．63、30．65、1．17 d,其中－10℃低温条件下短暂暴露,线虫全部死亡。此外,在0℃和5℃条件下经不同时间驯化后,－5℃暴露处理24 h,松材线虫的存活率显著提高,表明松材线虫耐寒性随着驯化时间的延长显著提高,但是0℃和5℃两种驯化温度对松材线虫的耐寒性增加差异不显著。     

松材线虫雌虫尾部形态和寄主的关系

Tenninal mucro of adult female was the distinct character between Bursaphelenchus xylophilus (Bx) and its allied species Bursaphe/enchus mucronatus (Bb). In general, Bx had no mucro. But it could have mucro in some situations. In the test, Bx without mucro was inoculated on Chineses pine (Pinus tabulaeformis) and Japanese black pine (Pinus thunbergii). The results showed that 85% of adult females Bx isolated from Chinese pine had terminal mucro. On Japanese black pine only 4.2% of adult females Bx had terminal mucro. Bx with terminal mucro from Chinese pine was re-inoculated on the fungus, Pestalotia sp. and Japanese black pine. It was found that 100% adult females had no terminal mucro on the fungus and 3.4% with terminal mucro on Japanese black pine.     

松材线虫病在辽宁省的潜在危险性分析

参照国内外专家对有害生物危险性分析方法，结合辽宁省森林资源状况，从松材线虫病的国内分布情况、在我省的潜在危险性、寄主植物的经济重要性、传播扩散的可能性以及危险性的管理难度等几个方面进行定性和定量分析，对松材线虫病的危险性做出综合评价。评价结果表明松材线虫病在我省属于高度危险的林业有害生物。     

自然侵染的松材线虫在松树体内的分布与消长

在松材线虫病为害季节，通过在发病区的不同小班选择刚出现枯萎症状的松树作为标准株，每隔一定时间，在不同部位取样、分离并计算松材线虫含量，结果表明受松材线虫侵染的松树、自出现初始症状的1个月左右时间，树冠枝条松材线虫含量显著多于其它部位，以后松材线虫在松树体内的分布趋于均匀。     

松材线虫在病木和天牛中分布特征分析

对病木的松褐天牛蛹室木屑、蛹室边缘木材、离蛹室5cm远木材以及松褐天牛进行线虫数量的镜检和分析，其线虫数量经方差分析差异不显著，而不同蛹室及其附近不同木材线虫分布的总量差异极显著。从松褐天牛上分离出的线虫数量差异相当大，从0-66.31条/cm^2不等。死的松褐天牛没有分离出松材线虫，活的松褐天牛经分离后也存在不携带松材线虫现象，而能够分离出线虫的雄雌天牛之间没有呈现一定的变化规律。     

应用虫线清乳油防治松材线虫病的施药技术

探讨了16%虫线清乳油防治松材线虫病的技术.通过林间药效筛选发现,用16%虫线清乳油的B配方防治松材线虫病的效果优于A、C配方,其是防治松材线虫病的首选药剂.无论是防治媒介昆虫成虫,还是防治活立木和枯死木内的幼虫、蛹;无论是树干打孔注药,还是林间低容量喷雾,均可取得良好防治效果.应用虫线清药剂处理林间松材线虫病枯死木或濒死木,是控制松材线虫病的一种有效、简便的方法;通过树干注入该药剂,则是预防具重要价值的松树发生松材线虫病的有效手段.     

福建省松材线虫病监测鉴定及其分布

2006—2009年分别在福建省松材线虫病(Bursaphelenchus xylophilus Nickle)重点监控区、重点预防区和一般预防区的重点区域设立了3 030个监测点,及时采集全省9个设区市48个县(市、区)发现的松枯死木样本,选择症状较典型和可疑松枯死木样本进行分离、鉴定。共快速分离鉴定标本176批次,计9 866个标本,其中含有松材线虫的标本2 819个,松材线虫病检出率为28.57%;鉴定样本的林分小班数2 214个,有松材线虫分布的小班690个,占31.17%。共监测出22个县级新疫点。2008年在野外首次监测到湿地松(Pinus elliottii)因感染松材线虫病后成片死亡。通过实践总结出一套松材线虫病鉴定技术。     

Distribution and persistence of emamectin benzoate at efficacious concentrations in pine tissues after injection of a liquid formulation

In an earlier paper the authors reported the creation of a novel emamectin benzoate 40 g litre(-1) liquid formulation (Shot Wan Liquid Formulation). The injection of this formulation exerted a preventative effect against the pine wilt disease caused by the pine wood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, and this effect lasted for at least 3 years. The present study was carried out to show experimentally that the marked effect of this formulation was due to the presence and persistence in pine tissues of sufficient amounts of emamectin benzoate to inhibit nematode propagation. A cleanup procedure prior to quantitative analysis of emamectin benzoate by fluorescence HPLC was devised. The presence of the compound in concentrations sufficient to inhibit nematode propagation in the shoots of current growth and its persistence for 3 years explained the marked preventative effect. Non-distribution of emamectin benzoate in some parts of the lower trunk suggested that the formulation should be injected at several points for large trees in order to distribute the compound uniformly to lower branches.     

Induction of resistance against pine wilt disease caused by Bursaphelenchus xylophilus using selected pine endophytic bacteria

Pine wilt disease (PWD) is the most destructive disease threatening pine worldwide. The disease is mainly caused by the pine wood nematode, Bursaphelenchus xylophilus, which is vectored by pine sawyer longhorn-beetles, Monochamus spp. This study aimed to select resistance-inducing pine endophytic bacteria for management of PWD. To set up a defence-related genes expression pattern for screening, four chemical inducers (salicylic acid, γ-aminobutyric acid (GABA), β-aminobutyric acid and α-aminobutyric acid) were tested in vitro on pine calli and in vivo on pine seedlings. Treatment with GABA had the greatest reduction in PWD severity on pine seedlings. The pattern of defence-related gene expression in calli treated with GABA was used to select potential resistance-inducing bacterial strains. In addition, 92 bacterial strains were isolated from pine tree needles and stems and were tested for expression of defence-related genes in pine calli in vitro. Among the tested strains, 13 showed a similar pattern to GABA treatment in at least four tested defence-related genes and were selected for the seedling assay. From the seedling assay, three bacterial strains (16YSM-E48, 16YSM-P180 and 16YSM-P39) showed significant reduction in PWD severity compared to the untreated control. Moreover, among the selected strains, cell-free culture supernatant of strain 16YSM-P180 significantly reduced PWD severity in inoculated pine seedlings. The selected strains were identified based on the 16S rRNA sequence as Pseudomonas putida 16YSM-E48, Curtobacterium pusillum 16YSM-P180 and Stenotrophomonas rhizophila 16YSM-P39. These selected strains are suggested as potential alternatives for management of PWD by induction of systemic resistance.