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.     

松材线虫病病树伐桩除害技术

伐桩是松材线虫病除治工作中最难除害的实体。试验表明剥皮挖虫法是伐桩除害最简便、最有效、最廉价的。与涂药除害法相比,效果提高44．2倍,成本下降14倍。     

浅谈松材线虫病检疫

阐述了松材线虫病发展和检疫现状,提出了检疫工作中存在的问题,并对如何进一步做好松材线虫病检疫工作提出了建议。     

松材线虫rNDA-ITS1区分子检测与鉴定

利用两对松材线虫特异性引物，分别对来自日本、美国和葡萄牙的松材线虫虫样进行PCR检测，成功扩增出330bp和220bprDNA-ITS1区基因片段，该方法对松材线虫成虫或幼虫均能作出准确鉴定。     

银杏叶和银杏外种皮提取液对松材线虫的毒杀作用

[目的]寻找高效低毒和低残留的植物源杀线剂。[方法]以甲醇、乙醇、丙酮和蒸馏水4种溶剂对银杏外种皮进行粗提,以甲醇、乙醇、乙醚和石油醚4种分析纯有机溶剂对银杏鲜叶进行粗提,都以蒸馏水作为对照,采用浓度稀释法测定不同溶剂提取物在24、48和72 h对松材线虫的抑制作用。[结果]银杏外种皮和银杏叶不同溶剂提取液对松材线虫都有抑制作用,外种皮提取液在200 mg/ml时,蒸馏水在第2天死亡率达到100%,丙酮提取液中的线虫死亡率也达到100%;外种皮提取液在20 mg/ml时,蒸馏水和乙醇提取液的死亡率达到84.9%。[结论]银杏外种皮提取液对松材线虫具有很好的抑制作用。     

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。     

松材线虫病的病理学研究进展

综述了松材线虫病早期症状的研究进展，同时，对线虫侵入后病树的生理学、组织学和病理学变化过程进行了概括。     

高频微波速杀松材线虫试验

总结了高频微波处理松材线虫病疫木的试验经验,以疫木中的松褐天牛和松材线虫死亡率达到100%且不损害疫木材质为目标,探索了工业上常用规格松木包装的最少处理时间和最适宜的微波发射量,为工业生产上的设备研制开发,积累相关实验参数.     

松材线虫入侵对嵊泗列岛黑松林植被演替的影响

对松材线虫入侵不同年数后嵊泗海岛黑松林生态系统的植被分层情况、种类丰富度、多样性指数、均匀度指数、生态优势度以及优势种类植物等进行了调查和分析,结果表明:松材线虫对嵊泗海岛松林生态系统造成较大的破坏,为害后,原来生态系统中上层乔木消失,植被逆行演替为以野桐、算盘子、小槐花及一年蓬、禾本科植物及莽草为主的杂草和灌丛.随为害时间的增长,群落的组成和结构也有一定变化,生态系统整体处于次生演替的早期阶段.