从日本进境鸡爪槭中截获朱顶红短体线虫

浙江出入境检验检疫局技术中心植检实验室从日本邮寄进境的鸡爪槭盆栽中检出一种短体线虫,该群体多为幼虫、雌虫,雄虫未见;通过形态学和分子生物学鉴定,将其鉴定为朱顶红短体线虫Pratylenchus hippeastri。该线虫在国内尚未见分布报道,属于中国禁止进境的检疫性有害生物(短体线虫非中国种),是中国首次截获该线虫。     

寄生柑橘的根腐线虫种类鉴定

从福建省的柑橘根部发现根腐线虫侵染,经形态学鉴定有咖啡根腐线虫(Pratylenchus coffeae)和玉米根腐线虫(P.ze-ae),咖啡根腐线虫为优势种。     

热水处理对薯蓣红斑病病原——咖啡短体线虫的影响

采用水浴法,对离体咖啡短体线虫、薯蓣块根内咖啡短体线虫以及薯蓣块根在不同温度条件下的敏感性进行测定。结果表明,在47、50、52、55 ℃处理条件下,杀死100%离体咖啡短体线虫的处理时间分别为6、2.5、1.5、1.5 min,而杀死100%薯蓣块根内线虫的处理时间分别为19、15、11、10 min;同时在上述温度下,分别处理35、30、25 min和25 min对薯蓣发芽没有影响。在同一温度处理中,随着处理时间延长,线虫的死亡率增加;而在不同温度处理中,随着温度升高,杀死线虫的时间逐渐缩短。综合上述试验结果,建议生产上防治薯蓣种薯内咖啡短体线虫的处理方法以52～55 ℃处理15～20 min为宜。     

Fish-toxicity problems of pesticides in Japan - the present situation and the policies of the Ministry of Agriculture and Forestry

Abstract

A survey of termite damage to groundnuts and an estimation of loss in yield was made between 1977 and 1979 in northern Nigeria. The foliage was attacked by Odontotermes. Damage was restricted to the Sudan savanna and loss in yield was less than 5%. Much more important was the damage caused by Microtermes lepidus Sjöstedt which attacked the pods, the tap root and the haulms. There was a linear relationship between the percentage of stands with the tap root invaded by Microtermes and the loss in yield. Damage varied from year to year, but the higher yield losses (up to 40%) were consistently recorded in the Sudan savanna. There was a significant relationship between the level of Microtermes damage and rainfall, the latter having a marked influence on foraging behaviour and the level of foraging activity. The chemical control of termites is economically viable on mechanised farms in the Sudan savanna, but cannot be justified on peasant farms, where yields are too low.     

Reaction of six Musa genotypes to root-parasitic nematodes

The reaction of six Musa genotypes to root-parasitic nematodes was evaluated under field conditions, together with the horizontal, and vertical distributions of the neomatodes within the soil profile. The numbers of Radopholus similis, Helicotylenchus spp., Meloidogyne spp. and of all nematodes in the excavated soil quadrant varied with Musa genotype. All genotypes were very susceptible to at least one nematode. Yangambi km5, Pisang Jari Buaya and FHIA-23 supported the lowest number of R. similis and Pisang Jari Buaya, the lowest number of Helicotylenchus spp. These three cultivars supported high numbers of Meloidogyne spp. Furthermore, FHIA-23 supported high numbers of Helicotylenchus spp. The horizontal and vertical distributions of R. similis in the root system of Valery, Gros Michel and FHIA-18 were very similar. By constrast, the distributions of Helicotylenchus spp., Meloidogyne spp. and the number of all nematodes varied slightly among the genotypes. Because Musa genotypes susceptible to a particular nematode showed a similar horizontal and vertical nematode distribution with populations concentrated in the vicinity of the plant base (0–30 cm horizontal distance and 30 cm depth), sampling at this site would be sufficient for the identification of the Musa plant reaction.     

咖啡短体线虫不同种群对番茄的寄生性和致病性

为了明确咖啡短体线虫对番茄植株的寄生性和致病性,利用温室盆栽接种和贝尔曼漏斗分离接种植株根际线虫的研究方法,测定了供试咖啡短体线虫5个不同地理种群对番茄的寄生性和致病性以及不同种群之间的致病力差异。结果表明:1)接种75d后供试咖啡短体线虫5个不同种群均能侵染番茄根系,并且在番茄根际的繁殖率(Rf)1,番茄是供试咖啡短体线虫5个不同种群的适合寄主;2)接种的番茄植株普遍长势弱,叶片黄化,根系减少,根部出现褐色病斑甚至坏死腐烂,线虫危害症状明显;3)接种番茄植株的株高、地上部鲜重和根鲜重等生长参数显著未接虫的对照组(CK),供试咖啡短体线虫5个不同种群对番茄均具有较强的致病性;4)寄主或地理来源不同的咖啡短体线虫不同种群之间的致病力存在差异,来自河南玉米的HN-K1种群的致病力最强,来自安徽小麦的AH-015A2种群的致病力最弱。综上所述,供试咖啡短体线虫5个不同种群对番茄均具有寄生性和致病性,但不同种群之间的致病力存在明显差异。本研究为番茄根腐线虫病害的识别与防控提供了一定的科学依据。     

Soil feedback effects to the foredune grass Ammophila arenaria by endoparasitic root-feeding nematodes and whole soil communities

In coastal foredunes, the grass Ammophila arenaria develops a soil community that contributes to die-back and replacement by later successional plant species. Root-feeding nematodes and pathogenic soil microorganisms are involved in this negative feedback. Regular burial by wind-blown beach sand results in vigorous growth of A. arenaria, probably because of enabling a temporary escape from negative soil feedback. Here, we examine the role of root-feeding nematodes as compared to the whole soil community in causing negative feedback to A. arenaria. We performed a 3-year sand burial experiment in the field and every year we determined the feedback of different soil communities to plant growth in growth chamber bioassays.In the field, we established A. arenaria in tubes with beach sand, added three endoparasitic root-feeding nematode species (Meloidogyne maritima, Heterodera arenaria and Pratylenchus penetrans) or root zone soil to the plants, and created series of ceased and continued sand burial. During three subsequent years, plant biomass was measured and numbers of nematodes were counted. Every year, bioassays were performed with the field soils and biomass of seed-grown A. arenaria plants was measured to determine the strength of feedback of the established soil communities to the plant.In the field, addition of root zone soil had a negative effect on biomass of buried plants. In the bioassays, addition of root zone soil also reduced the biomass of newly planted seedlings, however, only in the case when the field plants had not been buried with beach sand. Addition of the three endoparasitic root-feeding nematodes did not influence plant biomass in the field and in the bioassays. Our results strongly suggest that the negative feedback to A. arenaria is not due to the combination of the three endoparasitic nematodes, but to other components in the soil community, or their interactions with the nematodes.     

环介导等温扩增法（LAMP）检测最短尾短体线虫

为了快速、简便、准确地检测重要植物病原线虫—最短尾短体线虫（ Pratylenchus brachyurus ）,依据GenBank中短体线虫的线粒体DNA细胞色素氧化酶I（mtDNA COI）序列,设计了扩增最短尾短体线虫的环介导等温扩增（loop-mediated isothermal amplification,LAMP）引物,并对LAMP反应条件进行优化,成功建立了一种可特异、快速检测最短尾短体线虫的LAMP体系。该体系在64℃下反应60 min,扩增效率最高。用琼脂糖凝胶电泳、酶切分析和SYBR Green I染色均能特异检测到最短尾短体线虫的扩增产物。所建立的LAMP体系能从供试的9种短体线虫和另外10种植物线虫中特异检测出最短尾短体线虫,其灵敏度可检测到1/200条线虫DNA,是常规PCR的10倍。表明本研究建立的最短尾短体线虫的LAMP检测体系,可用于最短尾短体线虫的快速检测。     

Refinement of Passive Nematode Recovery from Cotton Growing High Clay Content Australian Vertisols

Vertisols are characterized by their high clay content, which can hinder assessment of their soil biology. Recovery of nematodes from vertisols with active techniques has indicated that free living nematode numbers within Australian vertisols are often low. Despite this, cotton yield losses due to the reniform nematode have recently been reported in Australia. In light of this and other changes in the cotton production system, we undertook a series of experiments to determine whether passive nematode extraction techniques could be applied to high clay vertisols. Existing published passive nematode recovery methods proved to be inefficient. The use of sodium hexametaphosphate as a clay dispersant was found to further reduce effectiveness. Instead, direct extraction of soil in Ludox at 1.1 g/cm³ followed by sieving was found to be as effective at recovering nematodes using Baermann funnel extraction from fresh soil but considerably quicker and three times more effective with dried soil.     

不同杀线剂对穿刺短体线虫的杀灭效果研究

为寻找杀灭短体属线虫有害生物的有效药剂,以穿刺短体线虫为供试线虫,测定了5种不同杀线剂对该线虫的杀灭效果。结果表明,5种供试杀线剂分别处理该线虫0.5h、1h和24h后,对该线虫均有一定的杀灭效果,顺序依次为:阿维菌素﹥噻唑磷﹥灭线磷﹥丁硫克百威﹥棉隆,其中阿维菌素和噻唑磷对穿刺短体线虫的杀灭效果较好,可作为备选药剂进一步研究。