HEC固化剂对土壤渗透性的影响

研究了HEC固化剂对黄土干密度和渗透性的影响,通过不同掺配比例的对比试验确定了HEC固化剂的最佳用量。结果表明,HEC固化剂对黄土干密度和渗透性能有很大改善作用。     

Thiabendazole as an iatrogenic agent in carrot black rot

Negligible amounts of carrot (Daucus carota L.) seed were produced in Brazil prior to the release of cv. Brasilia in 1982. This cultivar is tolerant of high temperature and resistant to leaf blight caused by Alternaria dauci (Kühn) Groves & Skolko (Vieira et al ., 1983). Since 1982 technology for production of Brasilia seed has developed rapidly and over 40 t of seed have been produced, representing more than 8000 ha planted. Fungicides are widely used on carrot root crops and growers have naturally extended their use to carrot seed crops. Mancozeb, thiabendazole, captafol and chlorothalonil, applied at weekly intervals, are the most common fungicides used although their efficacy in this new situation has not been evaluated.
A survey of pathogens associated with carrot seed production (Reifschneider & Della Vecchia. 1983) has shown that the most common fungal pathogen is Alternaria radicina Meier, Dreschler & Eddy, a species which is a common seed-borne pathogen in the USA (Rader, 1952) and has been present in Brazil since 1970 or earlier (Luz, 1970).
Since information concerning the control of A. radicina in carrot seed crops is lacking we established a preliminary fungicide experiment in July 1982 within a 5-ha commercial field planted with artificially vernalized roots of which 90% were infected, to varying degrees, with A. radicina . Plots were 25 m2 and each treatment (Table 1) was replicated five times, in a completely randomized design. Seeds were harvested manually at maturity and dried by forced air at c. 30°C. Infection by A. radicina was detected using the method of Soteros (1979) in which heat-treated seeds (100°C for 1 h) are plated on malt agar. A total of 200 seeds per plot (20 seeds per plate) were used. Identification of A. radicina was based on conidium and conidiophore morphology (Ellis & Holliday, 1972).     

土壤固化剂对不同土质固化性能影响的试验研究

为了探讨土壤固化剂对黄土渠基和土质集雨场的固化效果,进行了用于黄土地区WH型土壤固化剂的抗渗、抗冻、击实和无侧限抗压强度等物理力学性能试验,并与其它土质的试验结果进行了比较。结果发现用WH型土壤固化剂固化后黄土的抗冻和抗渗性能均得到较大提高,认为该土壤固化剂可用于黄土渠基和土质集雨场的防渗加固处理。     

山茱萸褐斑病病原鉴定

 山茱萸(Cornus officinalis)为山茱萸科(Cornaceae)山茱萸属植物, 其成熟干燥果肉(俗称枣皮)为我国常用名贵中药材。河南省南阳市(西峡、内乡和南召等县)为我国山茱萸主产区之一, 仅西峡县截止1990年已发展到500万株, 年产枣皮315万kg, 产值达4 200万元, 居全国首位。近年, 作者对西峡县山茱萸产区进行病害调查时发现, 由链格孢菌(Alternaria sp.)引起的山茱萸褐斑病发生普遍, 该病严重发生时可致植株95%以上叶片枯死, 落果率高达87%, 造成山茱萸大幅减产, 给当地果农带来严重经济损失。迄今, 未见链格孢菌引起的山茱萸病害报道。本研究对该病的病原菌进行分离鉴定, 以期为病害的防控提供依据。     

化学药物GSC不同浓度对白菜型冬油菜主要性状的影响

以白菜型冬油菜品种鉴94为材料,研究化学药物GSC的不同浓度对白菜型冬油菜主要性状的影响。结果表明,GSC处理两次后,导致植株生长势变弱,而对结实力无显著影响;对油菜花冠和花瓣的生长有一定抑制作用,随着化学药物浓度的增加,花冠直径和花瓣面积呈减小趋势,雄蕊长度逐渐缩短,雌蕊无显著变化,T7浓度处理(第一次0.5 mg·L^-1和第二次0.6 mg·L^-1浓度处理)后,花丝萎缩,花药干瘪,出现大量不育花粉。GSC可以诱导白菜型油菜产生雄性不育,随着GSC浓度的增加,不育株数和失活花粉数也逐渐增加,在T7浓度,植株不育株率达86.49%,失活花粉率达89.30%;同时用此浓度处理后花粉囊发育不良,绒毡层细胞提前解体或随花粉粒退化一同消失,小孢子团紧贴内壁,数量变少。试验说明化学药物GSC对白菜型冬油菜具有一定的杀雄效果,同时杀雄效果与药物浓度有一定关系。     

Identification of the causal agent of pistachio dieback in Australia

Symptoms associated with pistachio dieback in Australia include decline (little or no current season growth), xylem staining in shoots two or more years old, trunk and limb lesions (often covered by black, superficial fungal growth), excessive exudation of resin, dieback and death of the tree. Bacteria belonging to the genus Xanthomonas have been suggested as the causal agent. To confirm the constant association between these bacteria and the disease syndrome, the absence of other pathogens and the identity of the pathogen, we performed a series of isolations and pathogenicity tests. The only microorganism consistently isolated from diseased tissue was a bacterium that produced yellow, mucoid colonies and displayed morphological and cultural characteristics typical of the genus Xanthomonas. Database comparisons of the fatty acid and whole-cell protein profiles of five representative pistachio isolates indicated that they all belonged to X. translucens, but it was not possible to allocate the isolates to pathovar. Pathogenicity tests on cereals and grasses supported this identification. However, Kochs postulates have been only partially fulfilled because not all symptoms associated with pistachio dieback were reproduced on inoculated two-year-old pistachio trees. While discolouration was observed, dieback, excessive resinous exudate and trunk and limb lesions were not produced; expression of these symptoms may be delayed, and long-term monitoring of a small number of inoculated trees is in progress.     

多功能生物制剂对黄瓜白粉病的防治效应

通过盆栽和田间药效试验,研究了多功能生物制剂多霸2对黄瓜白粉病的防治效应。盆栽试验结果表明,先施用多霸2的100、200倍液后接种病原菌,可显著提高黄瓜的抗病能力,降低发病率,防效达到72.0%和69.2%,差异极显著(P<0.01);先接种后喷药多霸2的100、200倍液,在一定程度上能抑制病原菌的扩展,也具有防治作用,相对防效达到26.5%和23.1%,差异显著(P<0.05)。田间调查表明,在黄瓜苗期开始施用或未发病前施用多功能制剂,能有效预防白粉病的发生,具有很好的防治效应。多霸2的100、200倍液对黄瓜白粉病的防效与清水对照和常用药剂粉锈宁相比,差异都达到显著或极显著水平。其中,多霸2的100倍液使用效果最好,优于200倍液。     

The mode of action of the antifungal agent phosphite1

Field studies have established that phosphorous acid (phosphite) is an effective control against a number of plant diseases. However, the mechanism of control is not known. We have used Phytophthora palmiuora to investigate the action of phosphorous acid as an antifungal agent. Phosphite is toxic to Phytophthoru in uitro, but concentrations which completely inhibit growth in vitro are rarely ever achieved in phosphite-treated plants. Phosphite concentrations (1 m mol 1^-1) which do not inhibit fungal growth in vitro cause changes in the metabolism and cell-wall components. We suggest that phosphite, when present in plants in concentrations too low to control fungi in vitro, may cause modification of the fungal cell surface in such a way that the plant is able to recognize it as foreign and respond by normal defence mechanisms.     

Phomopsis cirsii: a potential biocontrol agent of Cirsium arvense

Cirsium arvense is a noxious perennial weed which has become an increasing problem in north European countries. Biological control by natural antagonists is of increasing interest to supplement mechanical and chemical control. Several attempts to use fungi such as Alternaria cirsinoxia, Puccinia punctiformis and Sclerotinia sclerotiorum as biocontrol agents have been initiated. No mycoherbicides against C. arvense have been developed and the search for aggressive pathogens continues. In a Danish survey, several fungi were isolated from C. arvense. Four are new records in Denmark: the white rust fungus Pustula andropogonis, the leaf spot fungi Ramularia cirsii, Septoria cirsii and Phomopsis cirsii. Our study shows that P. cirsii is pathogenic to C. arvense, causing stem canker and die back, and that it may have potential as a mycoherbicide against its host. Growth characteristics of P. cirsii on artificial media are described, as well as a scale measuring severity of visible symptoms of P. cirsii on C. arvense. The taxonomic characteristics of Phomopsis spp. are compared and discussed in relation to other records of Phomopsis spp. found on Cirsium spp. and C. arvense.     

江西番茄烂果病病原菌鉴定

In recent years since 2018, the disease of tomato fruit rot has been often noted in Jiangxi province. In order to ascertain the causal agent, common tissue isolation method was used to isolate the pathogen collected from 8 counties and cities of Jiangxi province. A total of 17 isolates was obtained, which exhibited similar phenotype on V8 agar plates with production of antheridia, oogonia and oospore indicating the characteristics of Phytophthora spp.. The pathogenicity test for the isolates showed the similar disease symptoms with that in the field and the pathogen was reisolated from the infected tomato tissues, which fulfilled the Koch’s postulate. BLAST search with rDNA-ITS, partial Ypt1 and β-tubulin gene sequences for 17 isolates showed 99%-100% of identities to Phytophthora capsici that in correspond with the clustering result of phylogenetic analysis for two represented strains. Combined with morphologic characteristic observation, pathogenicity test and sequence ana-lysis, the pathogen causing tomato fruit rot was identified as Phytophthora capsici. This is the first report of P. capsici causing fruit rot on tomato in Jiangxi province, China.     

辽宁西瓜衰萎病的病原菌鉴定

近年来,辽宁省新民市西瓜上发生一种新病害,病株根系衰弱、根毛数量减少,根部表皮粗糙,韧皮部木栓化,成软木塞状.随病情发展,植株叶 片自茎基部向顶部逐渐褪绿、变黄、枯萎,重病植株逐渐衰败、凋萎、死亡,故称之西瓜衰萎病.国际上,许多国家有关于西瓜、甜瓜的衰萎病发生的报道[1-5],而我国未见相关研究报道.在辽宁省西瓜产区田间调查发现,该病发生普遍,造成不同程度产量损失,重病田发病率高达30％,且有逐年加重趋势.据此,作者采集病害植株根部组织,分离获得病原菌,通过柯赫氏法则证病试验、病菌培养性状观察以及病菌rDNA ITS序列分析等试验,旨在明确该病害的症状、病原菌种类,为病害的防治提供理论依据.     

利用药物印迹法筛选化学杂交剂苯哒嗪靶标蛋白基因

为了筛选化学杂交剂苯哒嗪的靶标蛋白基因,以SQ-1(15%苯哒嗪乳油)处理的小麦品种西农1376为材料,以噬菌体λTripl Ex2为载体,利用SMART技术构建小麦单核期花药c DNA表达文库;以生物素为报告基团,合成苯哒嗪小分子探针,并利用该探针在c DNA表达文库中进行苯哒嗪靶标蛋白基因筛选。结果成功构建了一种新型有效的药物印迹筛选方法,获得了一条能够与苯哒嗪结合的蛋白基因c DNA序列,其编码蛋白属于DUF3456家族。研究结果为进一步明确SQ-1(有效成分苯哒嗪)的作用机理提供了依据。     

秸秆腐熟剂菌种筛选及鉴定

为了快速降解秸秆,本试验从土壤中筛选出一株产纤维素酶的酵母菌,编号为J-3。通过形态学特征、生理生化特征及26S rDNA序列分析鉴定菌株J-3为胶红酵母菌(Rhodotorula mucilaginosa)。经发酵条件优化产纤维素酶可以达到39.35U/mL,符合《农用微生物菌剂》GB20287-2006国家标准。为秸秆腐熟剂菌种群构建提供理论基础。     

天然抗病毒组合制剂对柿椒病毒病防效试验

经过筛选从苦丁茶、板兰根、酸膜叶蓼、椿叶、摩萝、香菇菌丝体和亚麻油渣中获得几种具抗病毒活性的生物材料。将上述材料抽提物经抗病毒效果及对病毒的作用方式试验,初步明确这些材料具有抗病毒侵染能力。把不同作用点的抗病毒材料经复配得到复配剂G,以烟草花叶病毒为防治对象,田间试验结果证明,复配制剂G可以控制病毒的侵染,对柿椒病毒病防治效果达81.12％,比单独使用各抗病毒材料制剂效果增加16％～58％。     

Identification of causal agent and management of grain discolouration in rice

Journal of Plant Diseases and Protection - Grain discolouration has been noticed in rice over the years in Guyana. The disease has been a serious problem in affecting quality and yield of rice. A...     

Field evaluation of capsaicin as a rodent aversion agent for poultry feed

Developing additional techniques for reducing animal feed contamination by rodents and controlling rodent populations is critical to efforts aimed at reducing the occurrence of Salmonella spp infection on poultry farms. Capsaicin, a compound found in chili peppers of the genus Capsicum, produces a burning sensation in the mouth of mammals and is used effectively as an animal deterrent for some pest species. Applied to poultry feed, capsaicin may be effective as an aversive agent to deter rodent feeding and enhance acceptability of rodenticide baits. We tested capsaicin-treated poultry diets (2000 and 3000 Scoville Heat Units, SHU) in no-choice feeding trials at four active New York farms in the winter of 1997-1998. At all farms, consumption of the 2000 SHU diet by rodents (Norway rats, Rattus norvegicus (Berk), and house mice, Mus musculus L) was significantly less than consumption of a control diet. Consumption of the 3000 SHU diet by rodents was significantly less than consumption of a control diet at three of the four farms. Overall, consumption of treated diets was 58-97% and 55-98% less than consumption of the control diet, for the 2000 and 3000 SHU diets, respectively. These reductions appeared to be related closely to the availability of alternative feed sources at these farms. Two-choice feeding trials involving a rodenticide bait (0.05 g kg(-1) brodifacoum) and the 3000 SHU diet demonstrated that Norway rats preferred the rodenticide to the capsaicin-treated poultry feed. Overall, rodenticide bait acceptance was high (95.6%) when offered simultaneously with capsaicin-treated poultry feed. Although poultry managers must utilize several techniques to manage rodent pests, the use of capsaicin-treated diets to reduce feed losses and increase rodenticide bait acceptance appears promising. Use of capsaicin-treated feed on poultry farms may substantially reduce feed contamination by rodents and ultimately the incidence of Salmonella infection in poultry.     

保水剂对小麦生长及生理特性的影响

为探明保水剂施用后对耐旱品种矮抗58生长及光合作用等的作用特征,通过大田试验,测定了保水剂不同用量(0,30,60,90 kg/hm2)的土壤水分、株高、叶面积、叶片相对含水量及光合特征等.结果表明:保水剂不但提高了各生育期表层土壤含水量,而且促进了20 cm以下土层土壤水分的提高.在拔节期,随保水剂用量的增加.叶片相...     

施肥与保水剂对半干旱区马铃薯增产效应的研究

在陇中半干旱区,探讨施肥和施加保水剂对马铃薯增产效应的影响.结果表明:保水剂、施肥都可以增加马铃薯产量,而保水剂与施肥结合对马铃薯的增产效果更加显著,体现了保水剂和施肥结合的交互作用.施用保水剂增加了冠幅(17.5％～52.7％),增加了马铃薯植株有效光合面积；在盛花期及块茎膨大期,保水剂结合施肥提高了马铃薯叶片光合速...     

Infection studies ofPseudomonas Tomato,causal agent of Bacterial speck of Tomato

Pseudomonas tomato, the causal agent of bacterial speck of tomato (Lycopersicon esculentum), was isolated on King B medium supplemented with penicillin and cycloheximide. An inoculum concentration of 10⁴-10⁵ colony-forming units per ml was used to obtain typical symptoms. Wounding of leaves by rubbing them with carborundum powder, or spraying with diluted wax solvent, significantly increased disease incidence. The best inoculation was obtained by subjecting the plants to 40°C for 30 min to 3 h or by incubating them for 24 h under mist prior to inoculation. The physiological age of the plants did not affect disease development. The bacteria survived in and were reisolated from soils, commercial seeds and plants after periods varying from 2 months to one year.     

Suppression of pine wilt disease by an antibacterial agent,oxolinic acid

BACKGROUND: Pine wilt disease (PWD) is very complex and has been reported to be caused by pine wood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, and its accompanying bacteria. However, there is no report on the control of PWD by antibacterial agent. The present study was performed to investigate disease control efficacy of antibacterial agents against PWD. RESULTS: Among six antibacterial antibiotics tested, oxolinic acid (OA) showed the strongest antibacterial activity against five bacteria isolated from three strains of pine wood nematode. In in vivo assay, it effectively suppressed the development of PWD in three‐year‐old seedlings of Pinus densiflora Sieb. & Zucc.; it showed 71% control when injected at 3 mg per seedling. A mixture of OA and the nematicidal agent abamectin (Ab) showed higher disease control efficacy against PWD than either OA or Ab alone. In addition, OA alone and a mixture of OA and Ab also controlled PWD in approximately 20‐year‐old pine trees under field conditions. CONCLUSION: This is the first report on the suppression of PWD by OA. The result strongly indicates that PWD could be controlled by antibacterial antibiotic alone and a combination of antibacterial and nematicidal agents. Copyright © 2010 Society of Chemical Industry