Diagnostic techniques for viroids

The fast growth of the human population forces us to produce more food, but higher crop production also leads to the fast spread of diseases. Plant pathology deploys a wide range of methods that do not provide an adequate solution to all disease losses. In the case of viroids, therapeutic means of control are not available; therefore control strategies are more focused on the development of reliable detection methods to quickly exclude the infected plant material. Although viroids are the smallest and simplest plant pathogens, their identification and detection is not straightforward. Each viroid–host combination is specific, and for reliable identification, all steps from sampling to final detection must be performed accurately. In this review, several methods for viroid detection in various host plants are discussed, including their advantages and disadvantages. Even though relatively new molecular methods enable fast and sensitive detection of viroids, a combination of different methods gives the most reliable identification. Techniques based on nucleic acids may be the future for viroid detection but they still cannot replace biological indexing, which is usually essential in epidemiological and aetiological studies.     

Rodent behaviour in relation to baiting techniques1

The use of poison baits is still the most important control method against commensal as well as field rodents. The baiting techniques used must be adapted to the ecology and behaviour of the target species. The various aspects of rodent behaviour influencing the effect of a control operation are discussed with emphasis on feeding behaviour, exploratory behaviour, neophobia, bait shyness, transporting, hoarding and territoriality. Advantages and disadvantages of sustained versus pulsed baiting techniques are discussed from a behavioural point of view.     

Problems and Programs in the Application of the Sterility Principle for the Control of Ceratitis capitata Wied.

In spite of the good results obtained in the control of Ceratitis under field conditions on the Italian islands of Capri and Procida, in Nicaragua and in the Spanish Murcia area, several problems connected with the sterile male technique still have to be solved. Mass rearing of the insects must be improved. Perhaps, total sterility of the males is not required and the necessary dose of irradiation must be studied in relation to its effect on their competitiveness in the field. In checking the efficacy of field operations the recapture of marked individuals will have to be supplemented or gradually replaced by the time-consuming assessment of egg-hatching and fruit-damage. Studies of the influence of environmental factors on population densities must be intensified.     

Management of fungicide resistance in practice1

Successful management of fungicide resistance includes many more aspects than just the design of an effective anti-resistance strategy. It involves all social groups engaged in plant disease control including industry, academia, extension and advisory services and, last but not least, the farmer. Various tasks must be carried out by these groups, and all must accept their share of responsibility. Only a comprehensive view of resistance management can help to prolong the useful life of the highly active new fungicides.     

部分马铃薯主栽品种对晚疫病的田间抗性研究

为摸清贵州省低海拔地区主栽马铃薯品种对晚疫病的抗性情况,2012年对贵州省13个主栽马铃薯品种进行晚疫病抗性鉴定试验。结果表明：Z-30、BP05-003（产量在25500kg／hm2以上）对晚疫病表现为中感,为早、中熟品种,适宜在低海拔发病不重的区域推广;滇黔芋2号、米拉（产量在13500kg／hm2以上）对晚疫病表现为感病,如在晚疫病常发区、重发区种植,生产上应加大防治力度;BPHFl01、20-4．5、威薯002为中感及感病品种,产量一般,为晚熟品种,适宜在高海拔地区种植,需要加强晚疫病防治并配套高产栽培技术。     

Allelopathic studies of common wheat (Triticum aestivum L.)

Wheat ( Triticum aestivum L.) is a common name for cereal grasses of a genus of the grass family, cultivated for food since prehistoric times by the people of the temperate zones and now the most important grain crop of those regions. It has allelopathic potential if used as a cover crop for weed control in various cropping systems. Research results indicate that, among modern varieties, there is a variable resistance potential against weeds. Numerous allelochemicals have been identified in wheat, mainly belonging to the categories of phenolic acids, hydroxamic acids and short-chain fatty acids. Some researchers conceived that wheat allelopathy is genetically controlled, but systematic research on gene behaviors is lacking. The negative effects of wheat on other crops under different agricultural production systems have been reported. Research is needed to determine the genetic control of wheat allelopathy prior to the development of allelopathic wheat varieties. Further research is needed to conduct in vitro studies to isolate, identify and quantify allelochemicals from living wheat plants at different growth stages. Also, the relationship between heritages of modern varieties and the allelopathic characteristics of wheat during their evolution and selection by humans is still unclear. There is also a lack of research on the modern varieties as to whether the allelopathic potential can be genetically transferred to the next generation. In the future, more models and assessment systems must be developed to illuminate the essence of allelopathy and the genomes of wheat with allelopathic traits should be constructed to make available allelopathic bioinformation on wheat.     

Plant Protection with and without Risks

Conventional plant protection procedures and integrated control are being compared in the light of their profitability. Control measures must be based on the density of pest populations. The fluctuations concerned can be usefully reproduced by means of a mathematic pendulum oscillating over a logarithmical scale of the densities. The model shows that better crop yields can be obtained through a reduced application of chemicals. Moreover, the expenditure incurred in integrated control is less and risks of failure are also lower.     

Treatments of soil—nematological aspects1

Treatments of soil to control plant parasitic nematodes constitute a complex problem because product losses, costs of treatments, efficiency of control and increases of yield are subject to multiple variables. To evaluate the situation, the whole system should be as carefully as possible analysed: nematode species must be identified and population densities determined; economical thresholds and the pedoclimatic conditions which affect distribution and persistence of nematicides should be investigated; rate of mortality that nematicides will induce at different doses and their side-effects on plants and environment need to be known. Although a great amount of information is available, this is often rather scattered, so much work is yet to be done. Integrated control is at present the only economical answer.     

匙叶天南星褐腐病的检出

 匙叶天南星是华南地区近几年新引入的一种重要花卉植物,1995年秋广东省广州市和顺德市栽种引自台湾的植株发生褐腐病,导致大量死亡。通过病原菌鉴定及对病土和各种种花基质进行的一系列试验,表明该病是由Cylindrocladium spathiphyli Schoulties et al.引起;病原菌是自台湾省随种苗和介质传入大陆的。建议在进行引种种苗时严格注意对植物根和介质的检疫。     

Developing Monitoring Programs for Livestock Producers

Many official monitoring programs have been developed, but few have been adopted by livestock producers. While these programs have relatively strong support from professionally trained managers, even their implementation is not consistent. New programs must address several important factors if they are going to be used. They must be used to help producers and managers make current decisions relating to their objectives and those broader resource objectives of society. Producers must understand how these broader objectives relate to their specific livestock objectives. These monitoring programs must help make proactive decisions, and be cost effective. Finally attempts must be made to make them flexible to deal with changing objectives that happen over time.     

干旱区水资源开发及合理利用的几个问题

在我国实施西部大开发战略中,西北干旱区必须合理开发利用水资源才能确保经济发展和生态安全,因此,必须重视和解决好以下几个问题：（１）提高水资源的利用效益;（２）适度开发利用地下水;（３）在有条件地区建设山区水利枢纽;（４）确保生态用水;（５０防治水质盐休和污染;（６）从长远考虑还需进行跨流域调水。     

Introduction to Weed Problems 1

I have approached the very wide topic of this paper by outlining the modern concept of weediness as traced from the beginnings of agriculture and then giving examples of some important present day weed problems from various parts of the world. Weeds have no place in nature and are essentially a reflection of the environment and of man's activities and desires. When these change, the weed flora responds and weed control methods may have to be modified. In developed agricultural systems, weed control has been revolutionised by herbicides which have also allowed major advances in methods of crop production and land and water management. As a result some classical weed species are no longer important whilst hitherto unimportant species have emerged as major problems. In many parts of the world there are obstacles to the introduction of chemical weed control techniques, and weed problems and control methods are much the same as they have always been. With the increasing world population and the need to provide more food, intensification of agriculture is inevitable. If weed control is not to be a limiting factor, more recognition and support must be given to weed science as an essential discipline of agricultural research.     

Weed problems and their management in rice fields of Malaysia: An overview

The available literature on weed problems and weed control in rice fields in Malaysia is reviewed and suggestions for future research are included. The problem of weed competition with rice is of great economic importance in the country because it causes a 10–35% reduction in grain yield. About US$4.10 million is spent annually on herbicides for rice alone, and this amounts to approximately 7% of the total expenditure on herbicides. The shift in methods of rice culture from transplanting to direct seeding has magnified the weed problem. The problem of weedy rice is particularly acute in the direct-seeding rice areas. Although a number of sulfonylurea herbicides (e.g. cinosulfuron, metsulfuron, bensulfuron and pyrazosulfuron) have been found to be suitable alternatives to the old herbicide 2,4-D, an integrated weed management program must be developed in order to reduce the problem of herbicide resistance in weeds. Weed control methods that are more friendly to the environment and affordable to farmers must be sought. Weed-competitive and allelopathic rice varieties must be produced. The problem of weeds in rice calls for systematic studies on biotechnological methods of control of weedy rice. Detailed studies on the biology and ecology of notorious rice weeds, particularly Oryza sativa L. (weedy rice), Echinochloa spp., Leptochloa chinensis (L.) Nees, Fimbristylis miliacea (L.) Vahl. and Limnocharis flava (L.) Buch. need to be done in order to formulate successful weed control measures.     

华南地区不同水稻品种对呋虫胺利用率的评价

稻田深施药和种苗带药是实现水稻精简耕作方式的有效途径,利用这些方式施用的杀虫剂,必须通过水稻种子或者根部吸收才能分布到植株各部位发挥药效。评价水稻品种间种子吸收杀虫剂的效率将有利于实现农药的减施增效。用1 mmol/L的呋虫胺浸泡处理51个水稻品种的种子后,采用超高效液相色谱法 (UPLC) 检测萌芽水稻幼苗根部和地上部中呋虫胺的含量,利用WinRHIZO软件分析其根部的形态指标,评价呋虫胺对种子萌发生长的影响。结果表明:不同水稻品种对呋虫胺的吸收量存在很大差异,其中桂育2号、合美占、93-11、桂华占和桂育7号的总吸收量相对较高;与清水浸种对照相比,经呋虫胺浸种萌发的水稻幼苗根变细,但根尖数、根长、根表面积和根体积变大,其中桂华占、泸香658、八桂香和聚两优750为高吸收利用呋虫胺的品种,且用呋虫胺浸种不会对水稻的生长造成不利影响。研究结果为从植物与农药互作的角度,提高农药利用率提供了前瞻性信息,也为推进稻田规模化种植提供了种质资源,为了解农药在水稻中的输导机理研究提供了线索。     

我国西北干旱地区环境与发展问题

西北地区具有资源优势，但由于生态环境恶化，经济结构不善，西北经济的发展必须注意与环境协调，资源开发必须与生态经济平衡。要控制人口增长、提高人口素质、发挥人才优势。欧亚大陆的贯通给西北经济发展带来了良好的机遇，要发挥资源优势，由资源型向资源加工型经济转变。     

Application of plant protection products by helicopter in Germany (legislation,requirements, guidelines,use in vineyards and forests,drift)1

In Germany, application of plant protection products by helicopter is only common in steep-sloped vineyards and in forests, where the use of conventional sprayers is nearly impossible. Because environment pollution, especially drift, is much higher than with ground equipment, the use of helicopters is subject to plant protection legislation as well as to air traffic regulations. BBA guidelines have been developed for application of plant protection products with aircraft. Each air-borne application must be based on a contract respecting these guidelines and must be reported to the proper authorities and announced to the public. The working airfields must be properly equipped and applications may only be performed under authorized weather conditions. The equipment of the aircraft must fulfil standards, especially for the spray tanks, the spray boom and the control devices, and so must the service stations on the ground.     

Control of food legume nematodes in the Mediterranean Basin1

Control of food legume nematodes should consider the nematode species, type of crops, whether for grain or fresh pod production, environmental conditions and the economics of the crops. In general, 3–4-year crop rotations could provide sufficient control of Heterodera goettingiana and H. ciceri and to a lesser extent also of Meloidogyne artiellia. Soil solarization has shown promise in controlling Pratylenchus thornei and H. ciceri on chickpea and has also been reported to be effective against Meloidogyne spp. The use of fumigants such as 1,3-dichloropropene or 1,3-dichloropropene + methylisothiocyanate and also of non-volatile nematicides (aldicarb, oxamyl, carbofuran, thionazin and fenamiphos) gives good control of these nematodes resulting in impressive yield increases in heavily infested soil. However, both nematicides and soil solarization are expensive and their use may not be economic in most cases. The use of resistant cultivars is, so far, of little importance due to very limited number of those with good agronomic characteristics. To ensure good yield of faba bean, attention must also be paid to producing seed stocks free from Ditylenchus dipsaci. In addition, quarantine regulations must avoid spread of this nematode among different countries.     

Standardizing the Evaluation of Brown Tree Snake Trap Designs

The introduced brown tree snake has had devastating impacts on the native vertebrate fauna of Guam. Trapping is the primary means by which brown tree snakes are removed, either in support of reintroduction of endangered species or to deter their movement from Guam in cargo. Traps used to control brown tree snake populations have been continually evolving since the 1980s. Before general operational implementation of a new design, the efficacy of new trap developments must be demonstrated. In this paper we combine the current knowledge about brown tree snake control objectives and practicalities, the information gained from a variety of brown tree snake trapping studies over the years, and fundamental statistical principles and methods to standardize procedures for testing developments in brown tree snake traps.     

扬州市麦田草相特点及杂草防除对策

为了摸清扬州地区麦田杂草种类、分布状况,通过倒“W”形九点取样法调查,结果表明麦田杂草有26科81种,其中里下河地区优势种为日本看麦娘、牛繁缕、菵草等;沿江地区优势种为菵草、日本看麦娘、牛繁缕等;丘陵山区优势种为日本看麦娘、猪秧秧、野老鹳等;同时发现当前存在着杂草抗药性增强、防治技术不到位等方面问题,提出了强抓土壤封闭处理、合理选用除草剂及开展技术宣传培训等对策。     

Exploiting chemical ecology to manage hyperparasitoids in biological control of arthropod pests

Insect hyperparasitoids are fourth trophic level organisms that commonly occur in terrestrial food webs, yet they are relatively understudied. These top‐carnivores can disrupt biological pest control by suppressing the populations of their parasitoid hosts, leading to pest outbreaks, especially in confined environments such as greenhouses where augmentative biological control is used. There is no effective eco‐friendly strategy that can be used to control hyperparasitoids. Recent advances in the chemical ecology of hyperparasitoid foraging behavior have opened opportunities for manipulating these top‐carnivores in such a way that biological pest control becomes more efficient. We propose various infochemical‐based strategies to manage hyperparasitoids. We suggest that a push‐pull strategy could be a promising approach to ‘push’ hyperparasitoids away from their parasitoid hosts and ‘pull’ them into traps. Additionally, we discuss how infochemicals can be used to develop innovative tools improving biological pest control (i) to restrict accessibility of resources (e.g. sugars and alternative hosts) to primary parasitoid only or (ii) to monitor hyperparasitoid presence in the crop for early detection. We also identify important missing information in order to control hyperparasitoids and outline what research is needed to reach this goal. Testing the efficacy of synthetic infochemicals in confined environments is a crucial step towards the implementation of chemical ecology‐based approaches targeting hyperparasitoids. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.