Root‐knot nematodes do not affect black root rot disease severity on watermelon and bottle gourd

The effects of root‐knot nematodes on black root rot of watermelon and bottle gourd were studied using field surveys and co‐inoculation tests with Meloidogyne incognita (southern root‐knot nematode) and Diaporthe sclerotioides. The results of the field survey suggested that root‐knot nematodes had little effect on either the severity of black root rot or infection with D. sclerotioides. None of the three fields showed a significant positive correlation between disease severity and nematode gall index, with low correlation coefficients. Co‐inoculation experiments under controlled conditions found no significant effect of root‐knot nematodes on black root rot of watermelon and bottle gourd based on area under disease progress curves (AUDPC). These results were supported by the quantities of DNA of the two agents in root tissues because no significant difference was found between dual‐ and single‐inoculation treatments with M. incognita and/or D. sclerotioides. These findings suggest that root‐knot nematodes probably do not affect the infection of watermelon or bottle gourd roots by D. sclerotioides or the incidence of black root rot in these crops caused by this fungus.     

利用杀线植物资源防治植物寄生线虫的研究进展

杀线植物指具有毒杀线虫的植物化合物。本研究综述了具有杀线虫作用的植物资源种类,包括大多数菊目和豆目植物,及从不同类群的植物和同种植物不同部位中分离到具有杀线虫的活性物质及活性代谢物。阐述了杀线植物及活性物质对植物寄生线虫的作用方式和作用机理,分析了影响植物杀线活性的因子,采用体内和体外2种测定方法测试提取物的活性,讨论了利用杀线植物资源防治植物寄生线虫存在的问题。为了寻找新一代杀线植物和活性物质,今后需要继续扩大对杀线植物资源种类调查和挖掘,明确杀线植物对植物寄生线虫的作用机理,加强对植物杀线虫活性成分的研究与应用以及从分子水平上加强对植物抗线虫品种资源的研究。     

Soil properties and perceived disturbance of grasslands subjected to mechanized military training: evaluation of an index

Mechanized maneuver training impacts the landscape by creating depressions, compacting soils, producing bare ground areas, transporting seeds of invasive plants, and crushing vegetation. We measured 3 physical, 13 chemical, and 2 biological soil properties and used a disturbance index (DI) based on perceptions of soil conditions on a military installation to assess the condition of 100 × 100 m plots (1 ha): 10 in 2002 and 10 in 2004. Potential DI scores range from 0 (no appreciable evidence of disturbance) to 1 (>95 per cent of the plot disturbed). Bulk density, porosity (%), and water content (%)—all at 5·1–10·0 cm depth, and nematode family richness (NFR) were significantly, negatively correlated (Spearman coefficients, r_s) with the DI of both years. The strong negative correlation (r_s = −0·69 in 2002, −0·79 in 2004) of NFR with the DI appears to reflect the status of nematode diversity and, therefore, may serve as a useful, inexpensive approach to rapidly assessing grasslands subjected to mechanized military training. Copyright © 2007 John Wiley & Sons, Ltd.     

阿苯达唑对波尔山羊消化道线虫的药效试验

为了观察阿苯达唑片对波尔山羊消化道线虫的驱除效果,探讨其对波尔山羊线虫病治疗的最佳剂量,将150只波尔山羊随机分成5组,其中设阿苯达唑7.5、15、30 mg/kg作为试验组,同时设左旋咪唑7.5 mg/kg作为药物对照组和阳性对照组,给药前后检查虫卵和虫体,计算虫卵转阴率、虫卵减少率和驱虫率,最后进行统计分析。结果显示,高剂量组和中剂量组的虫卵转阴率、虫卵减少率和驱虫率均显著高于低剂量组和盐酸左旋咪唑片对照组(P0.01),而高剂量组与中剂量组的虫卵转阴率、虫卵减少率和驱虫率差异不显著。15 mg/kg的阿苯达唑片对波尔山羊线虫的驱除效果安全。     

Differential effect of hot water treatment on whole tubers versus cut setts of yam (Dioscorea spp.)

BACKGROUND: The use of thermotherapy or hot water treatment (HWT) is recommended for the management of plant‐parasitic nematodes and other pathogens for a range of planting material, especially vegetatively propagated crops including yams, Dioscorea spp. The sprouting (germination) and consequent viability of yam following HWT, however, appear to be influenced by the post‐treatment method of planting (whole or cut setts) and cultivar. The present study was established to evaluate the sensitivity of the most popular yam cultivars in Benin and Nigeria, West Africa, to HWT at 50–53 °C for 20 min. RESULTS: Sprouting of both setts and whole tubers of most cultivars was affected by HWT. Across experiments, 47% of HWT material, compared with 61% of non‐HWT material, sprouted over 8 weeks. When cut into setts, 41% of HWT or untreated tubers sprouted, compared with 72% of whole tubers. Whole, untreated tubers had highest sprouting rates (84%), and setts following HWT had the lowest (38%). Yam planting material was also not completely free of parasitic nematodes following HWT. The reaction to HWT or cutting was highly cultivar specific. CONCLUSION: Yam cultivars vary in their sensitivity to hot water therapy. Care is therefore advised in selecting yam cultivars for HWT, especially when using cut setts. Copyright © 2009 Society of Chemical Industry     

植物根结线虫的实用防治技术

介绍了根结线虫的生活史及为害状况,总结了根结线虫的物理防治、化学防治、生物防治和农业传统防治4类防治技术。     

Pseudomonas oryzihabitans Suppresses Damage Caused by Root-knot Nematode Meloidogyne javanica on Tomato

Agricultural research made in recent years has found that many bacterial organisms act like biological control agents with minimal impact on the environment. These microorganisms and their toxic metabolites should be included in those which are acceptable to qualify a product as organic or integrated and enjoy all the benefits that entails. Hence, interest in the use of microorganisms as biological agents to protect crop plants against plant parasitic nematodes has been increasing. This study investigated the ability of.Pseudomonas oryzihabitans symbiotically associated with the entomopathogenic nematode Steinernema abbasi as a bioagent against plant parasitic nematodes which infected tomato crop. The bacterium is particularly effective against root-knot nematode in vitro affecting the behavior and mobility of root-knot nematode juveniles. Also, studies in planta demonstrated the efficacy of P. oryzihabitans by preventing tomato root system by invasion of juveniles of Meloidogynejavaniea when bacterial cells were applied to the root system before nematodes. This efficacy is dependent on bacterial cell concentration used and the time of the nematode exposure. However, a better nematode control might be achieved with multiple applications of the biocontrol agent. Furthermore, the results of this study provide evidence that the bacterium P. oryzihabitans produces metabolites, which have nematostatic effects.     

萝卜蚜新蚜虫疠霉的分离鉴定及其致病性测定

[目的]分离鉴定萝卜蚜的病原真菌,并测定其对萝卜蚜的致病性。[方法]采用形态学方法进行病原真菌种类鉴定,利用孢子浴方法对萝卜蚜进行致病性测定。[结果]初生分生孢子,卵形,双囊壁,单核,（24.7±1.4）μm×（10.7±0.9）μm,L/D=2.3±0.2。次生分生孢子形似初生分生孢子,大小为：（18.6±2.1）μm×（13.3±1.3）μm,L/D=1.4±0.2。菌丝段菌丝状,直径为（10.6±0.8）μm。分生孢子梗掌状分枝,直径（10.0±0.9）μm。假囊状体不分枝,基部粗大,直径（19.2±1.7）μm,向端部渐尖,直径（8.0±0.9）μm。假根单菌丝状,基部直径（21.0±3.0）μm,底端具有规则的盘状固着器。休眠孢子未见。该菌对萝卜蚜的致死中量为18.21 cfu/mm2。[结论]感染萝卜蚜的昆虫病原真菌被鉴定为新蚜虫疠霉,该菌对萝卜蚜表现出较强的致病性。     

香蕉穿孔线虫在我国入侵状况研究进展

香蕉穿孔线虫（Radopholussimilis）[中文又称相似穿孔线虫,隶属于线虫门（Nematoda）],是香蕉、许多花卉及经济作物最危险的专性寄生线虫。目前世界上许多国家和地区将其列为检疫对象。随着国际贸易的日益发展,该线虫传入我国的风险不断加大。该文概述了香蕉穿孔线虫在我国的截获情况;介绍了香蕉穿孔线虫的耐寒性能力、在土壤中的存活力及我国入侵区域的发病现状,指出阻止该检疫性植物线虫的侵入和扩散危害,对于保护我国农业生产安全具有重要意义。     

Assessment of new potato cultivars in Europe: a survey

Summary In 1994, a postal questionnaire was sent to 41 institutes in 27 countries to obtain information on the national potato cultivar testing programmes in Europe. Responses were received from 19 countries. Foliage, tuber and yield characteristics were assessed in all countries but the number of sites and replicated varied considerably between the countries. Cooking and taste qualities were measured in most countries using relatively simple methods but processing characteristics were tested less commonly. Susceptibility to the most common diseases, i.e. late blight, common scab, leafroll and PVY^o, was assessed in over 75% of the countries while resistance to another 21 disease and 4 potato cyst nematode pathotypes was assessed by various countries, depending on their national importance. Many of the assessments were based on records of natural infection although controlled inoculation tests were done more frequently for the more important diseases.