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1.
Which future for weed science? 总被引：2，自引：0，他引：2
Weed science is a discipline dealing with a serious biotic threat capable of causing heavy economic, environmental or aesthetic losses to society. In the past, we have been successful in providing efficient, relatively cheap and safe technologies to manage this threat in a variety of situations. We have been able to provide practical advice and options for the end-users based on a broad scientific knowledge. In order to continue this success, we need to anticipate the future and change faster than the world around us. Numerous opportunities are open to us. Weed science should enter the global climate change arena, getting involved in both mitigation (improving the carbon efficiency of agriculture and forestry) and adaptation (developing effective practices for the new crops, new production systems and the new weeds). We should find adequate answers to the new demands originating from the enlargement of farms and fields, the increased concern about the conservation of biodiversity and the growing consumer demands on food safety. We should look for new clients in non-agricultural sectors, offering them our proved expertise and know-how. We should try to exploit the new opportunities arising as a result of cross-fertilisation of weed science with other disciplines. At the same time, we need to be aware of some threats: the dominance of short-term commercial and political objectives in setting research agendas, the reduced R&D resources invested in the agrochemical industry in the development of new herbicides and the increasing 'publish or perish' pressure in the public research sector. 相似文献
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Should the declining diversity of weed communities in conventionally managed arable fields be regarded as a problem? The answer to this question has tended to divide researchers into those whose primary focus is on conserving farmland biodiversity and those whose goals are dictated by weed control and maximising yield. Here, we argue that, regardless of how weeds are perceived, there are common ecological principles that should underpin any approach to managing weed communities, and, based on these principles, increasing in‐field weed diversity could be advantageous agronomically as well as environmentally. We hypothesise that a more diverse weed community will be less competitive, less prone to dominance by highly adapted, herbicide‐resistant species and that the diversity of the weed seedbank will be indicative of the overall sustainability of the cropping system. Common to these hypotheses is the idea that the intensification of agriculture has been accompanied by a homogenisation of cropping systems and landscapes, accounting for both declines in weed diversity and the reduced resilience of cropping systems (including the build‐up of herbicide resistance). As such, weed communities represent a useful indicator of the success of rediversifying systems at multiple scales, which will be a central component of making agriculture and weed control more sustainable. 相似文献
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Is the current state of the art of weed monitoring suitable for site‐specific weed management in arable crops? 
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下载免费PDF全文 C Fernández‐Quintanilla J M Peña D Andújar J Dorado A Ribeiro F López‐Granados 《Weed Research》2018,58(4):259-272
Weed monitoring is the first step in any site‐specific weed management programme. A relatively large variety of platforms, cameras, sensors and image analysis procedures are available to detect and map weed presence/abundance at various times and spatial scales. Remote sensing from satellites or aircraft can provide accurate weed maps when the images are obtained at late weed phenological stages. Cameras located on unmanned aerial vehicles (UAVs) have been shown to be adequate for early‐season weed detection in a variety of wide‐row crops, providing images with relatively high spatial resolutions. Alternatively, weed detection/mapping systems from ground‐based platforms can achieve even higher resolutions using a variety of non‐imaging and imaging technologies. These ground systems are suited, in some cases, for real‐time site‐specific weed management. Despite this rich arsenal of technologies, their commercial adoption is, apparently, low. In this study, we describe the state of the art of remotely sensed and ground‐based weed monitoring in arable crops and the current level of adoption of these technologies, exploring major constraints for adoption and trying to identify research gaps and bottlenecks. 相似文献
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Martin V. Bauer Christian Marx Fabienne V. Bauer Dominique M. Flury Tammo Ripken Bernhard Streit 《Weed Research》2020,60(4):241-250
Research and development activities on non-chemical weed control methods to date have mainly focused on mechanical and thermal applications. Selectivity in mechanical weed control is obtained using dynamically actuated harrows. Selectivity in thermal weed control is obtained through a certain heat tolerance of the crop. In conservation agriculture (CA), weed emergence is partially suppressed by constant soil cover with crops or cover crops. Large amounts of plant residues therefore remain on the soil, which make mechanical methods inefficient or difficult to implement. And thermal methods need to prevent not only crop damage but also fire from situationally dry plant residues. In this review, technologies that can potentially be used for in-crop weed control in CA are discussed. The technologies reviewed include spot-flaming, electric resistance heating, electromagnetic irradiation and steam/hot water application. Their evaluation focuses on efficiency and specificity (spatial precision). This review indicates that existing equipment does not fulfil the spatial precision required in CA and that further research and development is required on this topic. In particular, the authors suggest further research on the use of laser diodes, micro-flames and capacitive coupling of electric fields. It seems that the use of automated imaging systems for weed/crop differentiation is a prerequisite in CA to enable automatisation of weed control. 相似文献
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Despite increased concerns regarding the heavy reliance of many cropping systems on chemical weed control, adoption of ecological weed management practices is only steadily progressing. For this reason, this paper reflects on both the possibilities and limitations of cultural weed control practices. Cultural weed control utilises a number of principles, predominantly: (i) a reduced recruitment of weed seedlings from the soil seedbank, (ii) an alteration of crop–weed competitive relations to the benefit of the crop and (iii) a gradual reduction of the size of the weed seedbank. Compared with chemical control, the general applicability, reliability and efficacy of most measures is only moderate, and consequently, cultural control strategies need to consist of a combination of measures, resulting in increased systems complexity. Combined with the trade‐offs connected to some of the measures, this hampers large‐scale implementation. It is argued that tailoring cultural weed management strategies to the needs and skills of individual farmers would be an important step forward. Research can aid in improving the utilisation of cultural weed control strategies by focussing on a broadening of the range of available measures and by providing clear quantitative insight in efficacy, variability in outcome and trade‐offs of these measures. 相似文献
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Potato late blight, caused by Phytophthora infestans, is a major disease in potato production throughout the world. In southern Sweden, hairy nightshade (Solanum physalifolium), an alternative non-crop host to the pathogen, is an increasing weed problem. Single-lesion leaves infected by P. infestans were collected from potato and hairy nightshade to determine phenotypic and genotypic population differentiation of P. infestans between the two hosts. Genotypic variation was estimated using microsatellites as markers. The results showed no genotypic differentiation in the samples between the two hosts. Aggressiveness tests were performed using the sampled isolates to cross-inoculate potato and hairy nightshade. The proportion of infected leaves, latency period, lesion growth rate, and sporulation capacity were measured. For isolates from hairy nightshade, the odds of infection were higher on both hosts combined. When tested on potato leaves, isolates from hairy nightshade showed a significantly shorter latency period and higher sporulation capacity compared with isolates from potato. This indicates that an alternative host can filter populations of P. infestans toward a higher aggressiveness, which could lead to increasing problems in controlling potato late blight. 相似文献
7.
The efficacy of any pesticide is an exhaustible resource that can be depleted over time. For decades, the dominant paradigm – that weed mobility is low relative to insect pests and pathogens, that there is an ample stream of new weed control technologies in the commercial pipeline, and that technology suppliers have sufficient economic incentives and market power to delay resistance – supported a laissez faire approach to herbicide resistance management. Earlier market data bolstered the belief that private incentives and voluntary actions were sufficient to manage resistance. Yet, there has been a steady growth in resistant weeds, while no new commercial herbicide modes of action (MOAs) have been discovered in 30 years. Industry has introduced new herbicide tolerant crops to increase the applicability of older MOAs. Yet, many weed species are already resistant to these compounds. Recent trends suggest a paradigm shift whereby herbicide resistance may impose greater costs to farmers, the environment, and taxpayers than earlier believed. In developed countries, herbicides have been the dominant method of weed control for half a century. Over the next half‐century, will widespread resistance to multiple MOAs render herbicides obsolete for many major cropping systems? We suggest it would be prudent to consider the implications of such a low‐probability, but high‐cost development. © 2017 Society of Chemical Industry 相似文献
8.
Abstract Calibration of knapsack sprayers and herbicide calculations are straightforward, yet these topics present difficulties for many users of herbicides. When the operator is thoroughly familiar with the sprayer and simple steps are followed, calibration is easy. Likewise, herbicide calculations are not difficult if the research worker understands the basic facts, can interpret the herbicide label and make ratio and proportion calculations. Easily‐followed steps are given for calibrating a knapsack sprayer and for calculating amounts of formulated herbicide to apply to research plots. 相似文献
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The use of bioherbicides containing fungal active ingredients or natural fungal molecules is one of the possible solutions to reduce the use of chemical products. This paper focuses on studies of bioherbicides, including both living fungi and natural fungal molecules, published in the last 45 years, and their associated weed targets; current problems in the development of bioherbicides are also discussed. Bibliometric methods based on the Web of Science database were used to analyse relevant articles published between 1973 and 2018. Overall analysis suggested that interest in bioherbicides extends over the preceding thirty years, when many potential microorganisms and natural fungal molecules were proposed. Furthermore, analysis of about 229 articles indicated an encouraging exploitable potential, although there is a real gap between the number of experimental studies and the small number of products currently on the market. A dozen fungal-based bioherbicides are on the market in the United States and Canada, while countries, such as China and South Africa, have one, and none is available in Europe. The active ingredients in these bioherbicides are living fungi, but no fungal molecule-based product is thus far on the market. Reasons for this gap include production hurdles, formulation process, ecological fitness, duration of herbicidal effects, and costly and time-consuming registration procedures. However, it is clear that analysis of fungus–plant interactions provides a promising source of bioherbicides that may be applied to appropriate cropping systems for environment-friendly, sustainable weed control. 相似文献
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As highly adaptable plants, weeds have evolved numerous mechanisms to evade control in agroecosystems. For example, reliance on herbicides has resulted in widespread evolution of resistance in many species. Minimising weed adaptation is a major driver for integrated weed management strategies. Crop mimicry is a notable example of weed adaptation, where weed species evolve to avoid control by mimicking aspects of the crop phenotype. Visual selection by hand weeding has been documented to select for crop mimics that are difficult to distinguish from the crop at the vegetative stage. With recent advancements in weed recognition technologies, image-based weed recognition for in-crop, site-specific weed control is on the cusp of becoming widely adopted. Whilst the control methods used in site-specific weed control will be varied (e.g., spot spraying or lasers), they will share weed recognition technology. Visual selection via image-based deep learning represents a selection pressure for weeds that can evade detection by mimicking crops. This mimicry may reduce weed recognition accuracy and thus weed control efficacy over time and result in difficult to manage mimetic weed phenotypes. Therefore, it is timely to explore the potential for selection of crop mimics by image-based weed recognition algorithms. 相似文献
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Robotic weeding's false dawn? Ten requirements for fully autonomous mechanical weed management 下载免费PDF全文
下载免费PDF全文 C N Merfield 《Weed Research》2016,56(5):340-344
While machines called weeding robots are now commercially available and many more designs are being actively researched, I contend that current machines are not truly robotic weeders, rather they are essentially self‐guiding vehicles carrying weeding tools. I consider true robotic weeders to be a far more difficult objective. While advances in robotics have been outstanding, the weeding component often appears to be an afterthought. I contend that the weeding is as complex as the robotics. A genuine weeding robot should be able to: (i) monitor the crop, weeds, weather and soil, (ii) decide when the crop should be weeded, (iii) choose the optimal weeder, (iv) take the weeder to the field, (v) adjust the weeder for optimal performance, (vi) continuously monitor the entire weeder for blockages and mechanical breakages and fix them in the field, (vii) continuously monitor and adjust the weeder's performance, (viii) return the weeder to the farmyard and (ix) clean, maintain and store the weeder, that is replace all human intervention. This ten‐point list both defines and is a guide to what is required for completely autonomous robotic weeding. Currently, this list is far beyond current technology and it may be decades before it is realisable. The aim of this study therefore was not to disparage the achievements of agricultural roboticists, rather it is to highlight the complexity and demands of mechanical weeding and therefore describe what is really required to create a true robotic weeder. I therefore hope it will guide and expedite research and lead to more rapid success for robotic weeding. 相似文献
14.
Does yield loss due to weed competition differ between organic and conventional cropping systems? 下载免费PDF全文
下载免费PDF全文 High weed abundance in organic crops is thought to be a key factor contributing to the greater yield loss in organic as compared with conventional cropping systems. However, even with greater weed densities than conventional systems, some organic systems have yields comparable to conventional systems, suggesting that cropping systems might differ in yield loss due to weed competition. The diversity in soil nutrient resources due to diversity in crop rotations and variable inputs might enhance crop tolerance to weed competition. We assessed the long‐term effects of contrasting levels of crop rotations (low, medium and high diversity) on weed density, weed biomass and wheat yield loss in organic and no‐till conventional cropping systems using a microplot study within a long‐term cropping systems trial at Scott, Saskatchewan, Canada. Weed density and biomass were found to be four times higher in the organic systems than in the conventional systems. Under standard weed management practices, organic had 44% lower yield than the conventional system. Lower yields in organic, even without weed competition, suggest that the lower yields are due to low soil productivity rather than weed competition. No differences in yield loss were observed among the organic and conventional systems or among the diverse crop rotations. We conclude that the organic management practices and/or increased crop rotation diversity did not enhance yield or reduce yield loss due to weed competition, due to the factors associated with lower soil fertility. 相似文献
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The rust fungus, Puccinia komarovii var. glanduliferae, has been introduced into the UK for biological control of the invasive weed, Impatiens glandulifera (Himalayan balsam). However, establishment of the pathogen has differed across the country, which may be partly explained by variation in plant genotype. The aim of this study was to examine whether there is a further layer of phenotypic resistance, provided by indigenous foliar endophytic fungi. Culturable endophytes were isolated from a number of different balsam populations, and the commonest species were inoculated into ‘clean’ balsam plants, to test their interactions with the rust. We found that endophyte communities within balsam are low in diversity and become more dissimilar with increasing distance between populations. Three endophytes (Colletotrichum acutatum, Alternaria alternata and Cladosporium oxysporum) were common and appeared to be antagonistic to the rust, reducing pustule number and mitigating the effect of the pathogen on plant biomass. I. glandulifera thus partially conforms to the endophyte-enemy release hypothesis, in that as an introduced species, it has an impoverished endophyte complement, acquired from the local environment. However, these endophytes represent a potential barrier to effective biological control and future weed control strategies need to find strains of rust that can overcome plant genetic resistance and the overlaying phenotypic resistance, conferred by endophytes. Future classical biological control programmes of weeds must therefore take into account the fungal bodyguards that invasive species may acquire in their introduced ranges. 相似文献
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An increasing water crisis as well as shortage of farm labor farmers in many Asian regions is forcing a shift from puddled transplanted rice to direct-seeded rice. The weeds, however, are a major constraint to the production of direct-seeded rice. In this perspective, a field study was carried out to evaluate various pre- and post-emergence herbicides and different possible integrated weed management practices in zero-till direct-seeded rice. Weed infestation decreased the rice yield by near about 75%. Co-culture rice with Sesbania followed by (fb) pendimethalin fb 2,4-D effectively reduced the total weed population (65.1%) and biomass (86.7%) at 30 days after sowing (DAS). The lowest total weed dry biomass at 60 DAS was recorded from bispyribac-sodium+azimsulfuron-treated plot and such tank mix application of herbicide performed better against diverse weed flora as compared to a single herbicide. Higher yield and more profit from zero-till direct-seeded rice were obtained with the application of bispyribac-sodium+azimsulfuron herbicides as a tank mixture or an integrated approach through cowpea green-manuring fb 2,4-D+glyphosate fb bispyribac-sodium by effective management of versatile weed flora. 相似文献
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In the conservation agricultural systems practised in Australia, cultivation is not commonly utilised for the purpose of weed control. However, occasional use of tillage (strategic tillage) is implemented every few years for soil amelioration, to address constraints such as acidity, water repellence or soil compaction. Depending on the tillage method, the soil amelioration process buries or disturbs the topsoil. The act of amelioration also changes the soil physical and chemical properties and affects crop growth. While these strategic tillage practices are not usually applied for weed control, they are likely to have an impact on weed seedbank burial, which will in turn affect seed dormancy and seedbank depletion. Strategic tillage impacts on seed burial and soil characteristics will also affect weed emergence, plant survival, competitive ability of weeds against the crop and efficiency of soil applied pre-emergent herbicides. If growers understand the impacts of soil amelioration on weed demography, they can more effectively plan management strategies to apply following the strategic tillage practice. Weed seed burial resulting from a full soil inversion is understood, but for many soil tillage implements, more data is needed on the extent of soil mixing, burial of topsoil and the weed seedbank, physical control of existing weeds and stimulation of emergence following the tillage event. Within the agronomic system, there is no research on optimal timing for a tillage event within the year. There are multiple studies to indicate that strategic tillage can reduce weed density, but in most studies, the weed density increases in subsequent years. This indicates that more research is required on the interaction of amelioration and weed ecology, and optimal weed management strategies following a strategic tillage event to maintain weeds at low densities. However, this review also highlights that, where the impacts of soil amelioration are understood, existing data on weed ecology can be applied to potentially determine impacts of amelioration on weed growth. 相似文献
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The effect of early weed emergence on crop seedling development has not been analysed within the context of a critical period study. Experiments were conducted to quantify the influence of a low light quality environment (i.e., low ratio of reflected red to far-red light (R/FR)) on maize seedling growth and development under non-limiting resource conditions. Weed-addition and -removal series were constructed, such that the effects of R/FR on seedling growth and development were isolated from those of direct competition. Maize seedlings responded to the presence of weeds within 24 h of addition by increasing plant height, which was followed by a subsequent reduction in the rate of leaf appearance. Seedling biomass and leaf area decreased linearly in the weed removal series with increasing duration of weed presence. Conversely, seedlings in the weed-addition series were unaffected. These results demonstrate that early exposure to weeds reduced the rate of seedling growth and development and that this effect was most pronounced if it was initiated upon emergence. This suggests that the existence of a period of developmental sensitivity to R/FR precedes the defined critical period for weed control in maize. These early physiological changes triggered by the R/FR ratio may contribute to the onset of the critical time of weed removal. 相似文献