Evaluation of Trichoderma spp. as a Biocontrol Agent Against Soilborne Fungi and Plant-parasitic Nematodes in Israel

The optimal conditions required to market Trichoderma as a biocontrol agent against soilborne fungi and nematodes are discussed. These include a proper formulation, an efficient delivery system, and alternative methods for Trichoderma's application.The implementation of Trichoderma in integrated pest management (IPM) can be achieved using a soil treatment which combines reduced amounts of biocides/fungicides and the Trichoderma preparation. Biocontrol activity can be increased by combining two (or more) types of biocontrol agents. Moreover, the construction of a genetically modified Trichoderma can lead to the improvement of certain traits which are absent or not highly expressed in the native microorganism isolated from its natural habitat.Different Trichoderma harzianum and T. lignorum isolates were tested for their nematicidal activity against the root-knot nematode Meloidogyne javanica. In short-term experiments, improved growth of nematode-infected plants and decreases in the root-galling index and the number of eggs per gram of root were achieved when nematode-infested soils were pre- exposed to the T. harzianum preparations. A long-term experiment resulted in improved growth and higher yield of nematode-infected plants, but no significant change in the galling index, either by pre-exposure of the fungus to the soil or by enrichment in the root-ball.As biocontrol is an integral part of the IPM philosophy, judicious use of Trichoderma against soilborne pathogens, when demonstrated to be consistently effective, practical and economic, can serve as a model for the introduction and implementation of other biocontrol means into IPM.     

松材线虫病防治技术存在问题及建议

就松材线虫病的防治技术所存在的问题以及相应的措施作详细的探讨,使松林资源得到有效的保护。     

关于我国松材线虫病治理工作若干问题的思考

就我国目前松材线虫病治理工作中存在的主要问题进行总结和原因分析,并根据我国目前松材线虫病发生和治理的现状,提出“十一五”期间我国松材线虫病治理的建议。     

微波处理松材线虫病疫木技术研究

该文对利用微波处理松材线虫病疫木技术进行了研究，结果表明：不论木材厚薄大小、含水量多少、在微波处理炉腔内怎样堆放，以及环境温度、微波功率等因素的如何变化，只要SWB-Ⅱ型隧道式微波除害处理设备显示的木材表面温度大于68℃，持续30min，就能有效地杀死松木中的松褐天牛和松材线虫。     

松材线虫病检疫检验取样方法的研究

对24个样本分别采用木条（10g)和0.6cm钻头钻取的木屑（10g)作为分离材料进行线虫分离，利用方差分析的方法对线虫分离结果进行分析，其差异不显著，两种取样方法对线虫检验的结果没有影响，对19个样本分别采用木条（10g)和用1cm的钻头钻取的木屑（10g和5g)3种分离材料进行线虫分离，同样利用方差分析对虫分离结果进行分析，其差异也不显著，3种分离材料对线虫检验结果同样没有影响。因此，利用电钻取样是可行的，这种方法快速简便，易于推广应用。     

沟环线虫属一新种-合川沟环线虫(垫刃目:环科)

合川沟环线虫Ogma hechuanensis n.sp.采自四川合川县柑桔根围土壤中，该种雌虫体较长，R＝64－74。第一头环直矩大于第二环。头体间缢缩明显。体中部鳞片列通常为11－12。鳞片近方形，近阴门处其先端呈锯齿状。口针长116．54－13．7．91μm,Rexp=19-22。阴门、肛门距尾端近，Rv=5-7，Ra=2－4。尾端钝，具数个鳞片，与近似种O.querci在以上特征上可相区别。     

接种用松材线虫分离种群的筛选

自2001年10月以来开展了“马尾松松材线虫抗性育种技术的开发”的项目工作，为选拔马尾松松材线虫抗性候补树，确保接种用的松材线虫虫源，对松材线虫分离种群的繁殖、致病力和增殖能力作了研究。对不同地区采取由松材线虫致死的19棵当年枯死木样品，用贝曼漏斗法从中分离出19个松材线虫分离种群，在25℃条件下，成功培养16个分离种群。在2a生黑松苗上进行接种，测定松材线虫的致病力。55d后在野外试验区的感病率为26．1％～97．6％，大棚试验区的感病率为84．4％～100％，野外与大棚内的加权平均感病率差20％以上，显示出松材线虫致病力由气温增高和土壤干燥而增强。分别对16个分离种群以相同的接种头数在PDA培养，其繁殖面积的快慢不同；以大量繁殖为目的，在同量的小麦培养基中以相同的接种量，各自的繁殖量也不同，每培养皿的繁殖量为98万～176万头。根据试验结果，选用致病力最强、繁殖力较强的广朱3B松材线虫分离种群作为接种用松材线虫的接种虫源。     

Exploring the limitations of pathophysiological indicators used for targeted selective treatment in sheep experimentally infected with Haemonchus contortus

Identifying which sheep to treat as part of a Targeted Selective Treatment approach to gastro-intestinal nematode control relies entirely on the efficacy of the indicators. Indicators such as FAMACHA© (anaemia), DISCO (diarrhea) and reductions in weight gains were designed specifically to reflect those sheep experiencing symptomatic consequences of infection. Using the gastro-intestinal nematode Haemonchus contortus as a model species, this study explored the utility and sensitivity of these indicators under controlled experimental conditions on 63 adult sheep. The potential effect of sheep with different H. contortus resistance phenotypes on indicator efficacy was compared in three different phenotypes, i.e. high (Blackbelly females), medium (Blackbelly rams) and low resistance (Romane rams). The potential effect of the H. contortus isolate on indicator efficacy was also explored by using four different isolates, with varying anthelmintic resistance capacities, to infect the sheep. We limited the study to the first month of infection to evaluate the interest of these indicators as an early predictive means for controlling infection. The pathophysiological indicators FAMACHA© and DISCO do not reflect infection intensity based on Faecal Egg Counts, nor do reductions in weight gains. FAMACHA© was however a good indicator of anaemia with strong correlations to haematocrit. There was little agreement among the three indicators to identify the same animals in need of treatment and even combining them did not increase their predictive value of infection intensity or relative host damage from infection. The indicator sensitivity was influenced by the H. contortus isolate and sheep resistance phenotype in which they were tested. One isolate was poorly infective but induced high levels of anaemia (FAMACHA©) and diarrhea (DISCO) compared to the three others. The FAMACHA© and DISCO had higher values in the sheep group with a medium resistance phenotype (Blackbelly rams) indicating higher levels of damage compared to the high and low resistance phenotypes. We conclude that there is no ‘one size fits all’ approach to the use of indicators for Targeted Selective Treatment and the indicators should be calibrated to farm-specific conditions to increase their efficacy.     

Partial organic substitution weakens the negative effect of chemical fertilizer on soil micro-food webs

Soil biotic communities play vital roles in enhancing soil nutrient cycling and soil fertility. Long-term excessive nitrogen (N) application is disadvantageous to the stability of soil food webs and affects arable soil health and sustainable utilization. Proper organic substitution is essential to improve soil health and alleviate the disadvantages of excessive chemical fertilization. However, the biological effects of various organic amendments on soil micro-food webs are poorly understood. In order to explore the effects of various organic amendments including stover, biochar and manure on soil micro-food webs (microbial and nematode communities), a field plot experiment with maize having five treatments viz., 100% urea (100% N), 70% urea (70% N), 70% urea plus stover (Stover), 70% urea plus cattle manure (Manure) and 70% urea plus biochar (Biochar) was conducted. Manure treatment increased the carbon (C) to N use efficiency of soil microbes, which contributed to the retention of soil C, while Biochar treatment elevated soil organic C (SOC) and soil pH. Additionally, Biochar treatment mitigated the negative effects of soil acidification on the soil micro-food web and reduced the abundance of plant parasites. Overall, the biological effect of organic amendments was distinguished from chemical fertilization (100% N and 70% N) through principal co-ordinates analysis. Negative relationships among soil properties, microbial and nematode biomass in the 100% N treatment were diminished in treatments where chemical fertilizer was reduced. The bottom-up effects on soil food webs were observed in organic substitution treatments. In conclusion, organic amendments improved soil fertility by regulating soil microbial and nematode communities in the cropland ecosystem, alleviated the negative effects of chemical fertilizer on the micro-food webs and controlled the trophic cascades among soil biota.