Sensitivity of populations ofBotrytis cinerea to triazoles,benomyl and vinclozolin

Sensitivity of field isolates (121) ofBotrytis cinerea from France (1992), Germany (1979–1992), Israel (1990) and the Netherlands (1970–1989) to the triazoles tebuconazole and triadimenol, the benzimidazole benomyl and the dicarboximide vinclozolin were tested in radial growth experiments. Resistance to benomyl (in 21 to 100% of isolates tested) and vinclozolin (in 25 to 71% of isolates tested) was common in most countries. EC₅₀s (concentrations of fungicides inhibiting radial mycelial growth ofB. cinerea on B5-agar by 50%) for tebuconazole and triadimenol ranged between 0.01–1.64 and 0.4–32.6g ml^–1, respectively, and were log-normally distributed. The variation factor (ratio between EC₅₀s of the least and most sensitive isolate tested) amounts 164 and 82 for tebuconazole and triadimenol, respectively. These values are comparable to those for azole fungicides applied in control of other pathogens. Hence, variation in sensitivity to triazoles can probably not explain limited field performance of triazoles towardsB. cinerea. Isolates from south west Germany (1992) were significantly less sensitive to tebuconazole than isolates collected earlier in Germany, Israel and the Netherlands. Such less sensitive populations may contribute to the limited field performance of DMI fungicides towardsB. cinerea. The sensitivity of isolates from south west Germany to tebuconazole was similar to that of DMI-resistant mutants generated in the laboratory. These mutants displayed stable resistance with Q-values (ratio between EC₅₀ of resistant mutant and wild type isolate) between 5 and 20. Sensitivity of field isolates and laboratory mutants to tebuconazole and triadimenol was correlated.     

Suppression of wheat-seedling diseases caused by Fusarium culmorum and Microdochium nivale using bacterial seed treatment

Snow mould, caused by Microdochium nivale , and seedling blight caused by members of the Fusarium complex, are cereal diseases of great economic importance in many temperate zones. In a glasshouse bioassay designed to enhance disease, about 600 plant-associated bacterial isolates obtained by different methods were screened for suppressive effects in wheat against infection caused by Fusarium culmorum . Although most of the isolates tested had a neutral effect on test plants and disease development, a few were synergistic to the pathogen and about one-fifth showed > 80% disease suppression. During five consecutive growing seasons, 164 bacterial isolates were tested in field experiments against both F. culmorum and M. nivale as causal agents of seedling blight. Tests for effects on yield in experiments with spring and winter wheat, performed in different climatic regions of Sweden, showed that disease-suppressive effects were repeatable. The most efficient isolates, three fluorescent pseudomonads and a species of Pantoea , suppressed disease equal to that of the fungicide guazatine, both with respect to crop stand and yield. Seed treatment with Pantoea sp. (isolate MF 626) increased yield by an average of more than 500 kg ha⁻¹ in six field experiments.     

节能日光温室中番茄灰霉病发生规律的研究

通过 3年对节能日光温室环境温湿度监测、病菌孢子捕捉和番茄灰霉病发生规律研究明确 ,一般年份 ,灰霉病在番茄叶片上表现为明显的始发期、盛发期和末发期等 3个阶段 ;果实发病后 ,即进入盛发期。温室中病菌的发生与病害呈正相关 ,病菌的高峰期较病害的高峰期提前10～15d。持续的低温、高湿、苗期带病等是引起番茄灰霉病发生的重要因子。提出要从优化设施环境等方面来控制番茄灰霉病的危害。     

Trichoderma Biocontrol of Colletotrichum acutatum and Botrytis cinerea and Survival in Strawberry

Trichoderma isolates are known for their ability to control plant pathogens. It has been shown that various isolates of Trichoderma, including T. harzianum isolate T-39 from the commercial biological control product TRICHODEX, were effective in controlling anthracnose (Colletotrichum acutatum) and grey mould (Botrytis cinerea) in strawberry, under controlled and greenhouse conditions. Three selected Trichoderma strains, namely T-39, T-161 and T-166, were evaluated in large-scale experiments using different timing application and dosage rates for reduction of strawberry anthracnose and grey mould. All possible combinations of single, double or triple mixtures of Trichoderma strains, applied at 0.4% and 0.8% concentrations, and at 7 or 10 day intervals, resulted in reduction of anthracnose severity; the higher concentration (0.8%) was superior in control whether used with single isolates or as a result of combined application of two isolates, each at 0.4%. Only a few treatments resulted in significant control of grey mould. Isolates T-39 applied at 0.4% at 2 day intervals, T-166 at 0.4%, or T-161 combined with T-39 at 0.4% were as effective as the chemical fungicide fenhexamide. The survival dynamics of populations of the Trichoderma isolates (T-39, T-105, T-161 and T-166) applied separately was determined by dilution plating and isolates in the mixtures calculated according to the polymerase chain reaction (PCR) using repeat motif primers. The biocontrol isolates were identified to the respective species T. harzianum (T-39), T. hamatum (T-105), T. atroviride (T-161) and T. longibrachiatum (T-166), according to internal transcribed spacer sequence analysis.     

冷冲高硬度材料模具失效的原因与对策研究

在日常的应用中,我们发现,制作材料是高合金钢的模具要比硬质合金制作的模具耐用,我们进而研究了其失效的方式以及失效的比例,研究结果显示,硬质合金的失效主要体现在掉渣和崩刃,而高合金钢的失效主要体现在正常的磨损方面。在制作的过程中,高合金钢会由于在加热的不适当而使得碳化物不均匀,或者使得硬度不稳定等原因而没有充分发挥材料的潜在能力,文章对如何提高高合金钢的寿命提出了具体方案。     

浅谈地下车站侧墙大块定型移动模架施工技术

随着城市地铁的飞速发展,地铁车站在条件满足的情况下大都采用明挖法施工。在施工主体侧墙时采用满堂红支架法施工,但因施工时工期较长且易存在一些质量通病,因此,近年来大块定型移动模架被得到了广泛的应用。     

42.4%唑醚·氟酰胺悬浮剂对番茄叶霉病的防效

[目的]探讨42.4%唑醚·氟酰胺悬浮剂对番茄叶霉病的田间防治效果。[方法]以10%苯醚甲环唑水分散粒剂和70%甲基硫菌灵可湿性粉剂为对照药剂,采用小区试验研究42.4%唑醚·氟酰胺悬浮剂对番茄叶霉病的防治效果。[结果]42.4%唑醚·氟酰胺悬浮剂在剂量为150.0~225.0 g a.i./hm2时,对番茄叶霉病的防治效果为83.37%~91.63%,与10%苯醚甲环唑水分散粒剂120.0g a.i./hm~2对番茄叶霉病的防治效果无显著差异,但显著高于70%甲基硫菌灵可湿性粉剂562.5 g a.i./hm~2的防治效果。[结论]42.4%唑醚·氟酰胺悬浮剂可广泛用于番茄叶霉病的防治。     

Yield performance and pest resistance among peanut genotypes when grown without fungicides or insecticides

Yield trials without fungicides or insecticides were conducted four consecutive years (2007–10) at the University of Georgia, Coastal Plain Experiment Station, Tifton Campus to evaluate for peanut (Arachis hypogaea L.) pest resistance. The most endemic diseases in the southeast U.S. are tomato spotted wilt (TSW) caused by Tomato spotted wilt virus, white mold (WM) caused by Sclerotium rolfsii Sacc, and both early and late leaf spot caused by Cercospora arachidicola Hori and Cercosporidium personatum (Berk & Curt.) Deighton, respectively. The most endemic insects are tobacco thrips (Frankliniella fusca Hinds) and potato leafhopper (Empoasca fabae Harris). Results from these replicated field tests showed significant differences (P ≤ 0.05) among advanced Georgia breeding lines and cultivars. Three Georgia cultivars ‘Georgia-01R’, ‘Georgia-05E’, and ‘Georgia-10T’ consistently produced among the best yields with high levels of resistance to TSW, white mold, leafhoppers, and leaf spot each year. Georgia-01R is a multiple-pest-resistant, runner-type cultivar with late maturity; whereas, Georgia-05E is a multiple-pest-resistant, virginia-type cultivar with medium-late maturity. Georgia-10T is a new runner-type cultivar with high level of TSWV and white mold resistance and late-maturity, similar to Georgia-01R, one of its parents. However, Georgia-10T does not appear to have the high level of leaf spot and leafhopper resistance as Georgia-01R, but it still had high yields in the absence of fungicides or insecticides.     

甘肃陇西黄芩灰霉病病原菌分离鉴定及田间药剂防治

为探明黄芩(Scutellaria baicalensis Georgi)茎基部和根部灰霉病的病原菌,本文于2019—2021年春季对甘肃陇西县采集的黄芩病样进行病原菌的分离培养,运用形态学和内转录间隔区(Internal transcribed spacer, ITS)、甘油醛-3-磷酸脱氢酶(Glyceraldehyde-3-phosphate dehydrogenase,G3PDH)、热激蛋白60(Heat shock protein 60,HSP60)和RNA聚合酶亚基II(The second largest subunit of the nuclear RNA polymerase enzyme II,RPB2)多基因方法鉴定,采用菌丝生长抑制法进行药剂室内毒力测定和田间药剂防治试验。结果表明：引起黄芩灰霉病的病原菌为灰葡萄孢(Botrytis cinerea),春季发病时表现为地上部分枯死不发芽,靠近地表的根表面呈暗绿色水渍状,随后地下根木质部变软呈黄褐色腐烂,病健交界明显;室内毒力测定表明,97%咯菌腈对灰葡萄孢菌的抑菌作用最强,EC₅₀为0.01...     

New Design of Pre-amplification Circuit for EEG Signals

In the measurement of EEG signals ,the pre - amplification electrical signal of brain is the most importantant and key link. Whether the design is excellent or inferior is related to the electrical signal detection system of brain directly. The design of this circuit has been paid attention to by domestic and international expert all the time. On the basis of existing biological electricity amplifier which is studied, the authors consult the electric amplifier circuit of living beings designed , such as reference , improve and design a new-type and high performance electrical signal characteristic of brain in . The circuit has prevented the traditional design from enlarging the miscellaneous simulation of the circuit and straining the wave link, otherwise, this circuit is of simple structure , low cost, and convenient debugging. The paper has detailed theoritic analysis and experimental results to prove this circuit, which offered a new train of thought for reseach and development of brain electrical amplifier and other faint biological electricity amplifiers . This curcuit has be expected to win extensive application.