Weed Scientist Research Articles

Introduction: The Civic Reconstruction of Higher Education and the Future of the Good Society

Introduction: The Civic Reconstruction of Higher Education and the Future of the Good Society

The Citizen Professionalism of a Weed Scientist

Abstract What can we learn about the political roles and work of professionals from a self-described “weed scientist” from Minnesota? A lot, it turns out. This essay draws on stories and judgments expressed in an oral history interview to help us imagine what democratic or citizen professionalism in a highly technical field can look like: what it involves, what promises and dangers it holds, what it’s up against, and why and how it matters.

A most troublesome weed

North Dakota State University weed scientist Brian Jenks can tell you exactly when, where, and how Palmer amaranth first appeared in his state. In 2018, the noxious weed sneaked, via seed, across s...

Cover Crops for Weed Control

Photo by Edwin Remsberg and USDA-SARE Research on the effects of cover crops seems to be everywhere these days—from use in organic farming to home gardens and to traditional row crop systems. The studies seek to determine how cover crops influence erosion, soil compaction, microbial communities, weeds, and soil nutrients to name a few. However, like many topics, there is not a clear consensus about the effects of cover crops. Results that are positive, neutral, and negative have been published, making it difficult for those who may be interested in using cover crops to determine if they are an appropriate tool. This lack of consensus was noticed by weed scientist O. Adewale Osipitan when he attended a workshop where the topic of cover crops to reduce weeds was presented. Coming away from the workshop with more questions than answers, Osipitan, who is currently a post-doctoral researcher at the University of Nebraska–Lincoln, says, “I felt the answers to these questions required collection and analysis of broad-based data from different contradictory findings to arrive at a quantitatively summarized answer.” Because of this, he decided to conduct a meta-analysis. Being new to this approach, he consulted with colleagues who had experience in it and decided to focus on the effect cover crops have on weed biomass and the yield of the main crop grown after the cover crop. An initial search of the literature turned up 894 papers, and based on pre-selected inclusion criteria, 46 were included in the analysis. Osipitan points out the importance of having pre-selected criteria, which makes it easy to determine what papers should be included. From this analysis, Osipitan and co-authors, Anita Dille, Yared Asefa, and Stevan Knezevic determined that cover crops can provide effective weed suppression. This will come as no surprise to many, but what is more interesting is that in addition to providing weed suppression, this analysis demonstrated that there was either no effect or a positive effect on the yield of the main crop. The main crops, or cash crop that followed the cover crop, were categorized as grains or vegetables. There was a positive yield benefit of cover crops for vegetable crop yields and no impact on grain crop yields. Although this approach provides evidence that cover crops will have no effect or a positive effect on the cash crops growers depend on, it is important to note the potential for a bias toward positive results in this approach. Osipitan mentions that there is the potential for publication bias to influence the results of a meta-analysis. Researchers often rely on peer-reviewed publications to determine what data to include, and peer-reviewed publications are less likely to include non-significant or negative results. It may be beneficial to include unpublished data from graduate student theses and dissertations, which are often unpublished because the results are non-significant, to strengthen the analysis. This meta-analysis may aid in giving farmers interested in using cover crops some peace of mind that they will not have to sacrifice yields. “A take home for farmers is that if cover crops are properly selected and properly managed, there would be weed suppression benefits comparable to what tillage or herbicide could provide, particularly during the early part of the main crop's growing season, after cover crop termination,” Osipitan says. There are additional environmental benefits to reducing herbicide use too as herbicides often run off and impact non-target organisms like aquatic vegetation, amphibians, and fish and can lead to herbicide-resistant weeds. View the open access article in Agronomy Journal, “Cover Crop for Early Season Weed Suppression in Crops: Systematic Review and Meta-Analysis,” at: https://doi.org/10.2134/agronj2017.12.0752. A second meta-analysis by Osipitan and colleagues in Crop Science looks at how management of cover crops and main crops influence cover crop weed suppression. See https://doi.org/10.2135/cropsci2018.09.0589.

Weed Science Education at the Tertiary Educational Level in Nigeria

Weed Science is a discipline in that it deals with the study of vegetation management in agriculture, horticulture, aquatics, right-of-way, estates or amenities, essentially anywhere plants need to be managed. It involves the study of all the tools available for this purpose. In comparison with other plant protection disciplines, it has not enjoyed being a distinct discipline. Its study has in most cases been aligned with degrees in Agriculture and Agricultural related discipline. It has always been a component of degrees in Agricultural Science or Crop Science in Nigerian universities. This paper reviews the current status of Weed Science education in Nigeria. In Nigerian universities courses on weed control is part of degree programmes in Agriculture, Horticulture and/or Biological/Plant Sciences, where only aspects of weed characteristics and their control with herbicides, are taught in the third or final years. At the Masters or graduate levels it is taught where there is a Resident Weed Scientist. Because of government’s insensitivity the growth and development of professionalism is stifled. To date, of 149 universities in the country, only 58 of them offer one form of a course or the other that is related to weed science, constituting 44.8%. There were no Weed Scientists present in all the categories of Polytechnics, hence limiting per capita availability of Weed Scientists in the country. This situation does not engender participation or entrant of new members into the discipline. Inadequate funding of the education and agricultural sectors has been the bane of developing adequate manpower and expertise needed in the area. For instance the Weed Science Society of Nigeria has been in existence since 1971, but their presence has not adequately influenced professionalism due to lack of appropriate policy environment. Weed Science education in Nigeria has not found its rightful space in the national polity. If national agricultural development is to remain afloat, Weed Science education should be properly appropriated through adequate budgetary allocation to the Agriculture and Education sectors. This will enhance the quality of teaching and recruitment of Weed Scientist.

Integrated weed management for sustainable agriculture

Eminent weed scientist Robert Zimdahl has attracted prominent weed ecology experts from Canada, France, Australia, Israel, and U.S., primarily from universities and national research groups, to pre...

Using ecology and technology to Control Weeds

Using ecology and technology to Control Weeds

Identification of glyphosate resistance in Russian thistle in northeastern Oregon

Glyphosate is the first herbicide choice for growers in the Pacific Northwest to control Russian thistle after harvest and during summer fallow. However, overreliance on this chemical has already led to the occurrence of herbicide‐resistant weeds. In fall 2015, complaints from farmers about lack of Russian thistle control with glyphosate prompted an Oregon State University weed scientist to test whether there were glyphosate‐resistant populations in northeastern Oregon. Earn 0.5 CEUs in Integrated Pest Management by reading this article and taking the quiz at www.certifiedcropadviser.org/certifications/self‐study/830.

Weed Research – our aims and editorial policies

<i>Weed Research</i> – our aims and editorial policies

Weed control changes and genetically modified herbicide tolerant crops in the USA 1996–2012

Crops that have been genetically modified (GM) to be tolerant to herbicides have been widely grown in the USA since 1996. The rapid and widespread adoption of this technology reflects the important economic and environmental benefits that farmers have derived from its use (equal to $21.7 billion additional farm income and a 225 million kg reduction in herbicide active ingredient use 1996–2012). During this time, weed control practices in these crops relative to the ‘conventional alternative’ have evolved to reflect experience of using the technology, the challenges that have arisen and the increasing focus in recent years on developing sustainable production systems. This paper examines the evidence on the changing nature of herbicides used with these crops and in particular how farmers addressed the challenge of weed resistance. The evidence shows that use of the technology has resulted in a net reduction in both the amount of herbicide used and the associated environmental impact, as measured by the EIQ indicator when compared to what can reasonably be expected if the area planted to GM HT crops reverted to conventional production methods. It also facilitated many farmers being able to derive the economic and environmental benefits associated with switching from a plough-based to a no tillage or conservation tillage production system. In terms of herbicide use, the technology has also contributed to a change the profile of herbicides used. A broad range of, mostly selective herbicides has been replaced by one or 2 broad-spectrum herbicides (mostly glyphosate) used in conjunction with one or 2 other (complementary) herbicides. Since the mid-2000s, the average amount of herbicide applied and the associated environmental load, as measured by the EIQ indicator, have increased on both GM HT and conventional crops. A primary reason for these changes has been increasing incidence of weed species developing populations resistant to herbicides and increased awareness of the consequences of relying on a single or very limited number of herbicides for weed control. As a result, growers of GM HT crops have become much more proactive and diversified in their weed management programs in line with weed scientist recommendations and now include other herbicides (with different and complementary modes of action) in combination with glyphosate, even where instances of weed resistance to glyphosate have not been found. The willingness to proactively diversity weed management systems in the GM HT crops is also influenced by a desire to maintain effective weed control and hence continue to enjoy the benefits of no tillage and conservation tillage. Nevertheless, despite the increase in herbicide use in recent years, the use of GM HT technology continues to deliver significant economic and environmental gains to US farmers.

Saddling up for Louis

Saddling up for Louis

Principais aspectos da resistência de plantas daninhas ao herbicida glyphosate

A seleção de biótipos de plantas daninhas resistentes a herbicidas na agricultura brasileira e mundial é um fenômeno já constatado e relatado para praticamente todos os herbicidas em uso na agricultura. A confirmação de um novo caso de resistência de planta daninha ao herbicida glyphosate através da espécie Lolium multiflorum (azevém), que corresponde ao primeiro caso relatado no Brasil para esse herbicida, preocupa o meio científico, produtivo e industrial, devido à importância desse herbicida para o manejo de plantas daninhas das diversas culturas. Assim, a discussão e compreensão do fenômeno da resistência são fundamentais para prevenir ou retardar a seleção de biótipos resistentes a herbicidas, sendo este o objetivo principal do presente artigo. São discutidos aspectos referentes a fatores ligados às plantas daninhas e aos sistemas de produção que interagem na seleção da resistência a herbicidas, o potencial de seleção de plantas daninhas resistentes ao glyphosate, o fluxo gênico e as formas de manejo e prevenção da resistência.

Ethics in weed science

Weed science, like most sciences, has distanced itself from social and ethical discourse in theory and practice. This symposium illustrates my point. The 38th meeting of our society is the first time there has been a formal discussion of the ethical aspects of our work. Weed science, we often believe, is value free, as science ought to be. But neither basic nor applied weed science is value free; they are value laden. Operative values include meeting basic human needs through improved food production, promoting the common good through abundant food, improving people's lives through efficient production of safe food, achieving agricultural sustainability, and increasing efficient food and fiber production and farmer profit. Truth pursued via the scientific method is valued and respected, as is belief in the goodness of scientific and technological progress. Most of these values rest on an ethical foundation known as utilitarianism. Most weed scientists and their colleagues in agricultural sciences are utilitarian in that they believe their work should be useful to humans and should promote the greatest good for the greatest number of people. What weed scientists believe and stand for and the validity of the ethical foundation of their utilitarian convictions ought to be central subjects of the weed scientist's research and teaching. Ethical reflection does not necessarily imply criticism or a need for reform, but it does demand intellectual clarity and an ability to affirm who we are, what we do, and what we value. Weed scientists should engage in an exchange about the ideas that are the end result of their experiences and discuss the experiences that give shape, substance, and depth to those ideas. In the absence of internal ethical reflection and value clarification, external distortions—including public criticism—will define the moral universe weed scientists must work in. Without embarrassment, weed scientists have to learn to ask about the ethical foundation of their science.

Utilization of Allelopathy for Weed Management in Agroecosystems

AbstractBiorational alternatives are gaining increased attention for weed control because of concerns related to pesticide usage and dwindling numbers of labeled products, particularly for minor‐use crops. Allelopathy offers potential for biorational weed control through the production and release of allelochemics from leaves, flowers, seeds, stems, and roots of living or decomposing plant materials. Under appropriate conditions, allelochemics may be released in quantities suppressive to developing weed seedlings. Allelochemics often exhibit selectivity, similar to synthetic herbicides. Two main approaches have been investigated for allelopathic weed suppression. One is use of living rotational crops or mulches that interfere with the growth of surrounding weeds [e.g., tall red fescue, Festuca arundinacea Schreb.; creeping red fescue, F. rubra L. subsp. commutata; asparagus, Asparagus officinalis L. var. altilis); sorghum, Sorghum bicolor (L.) Moench; alfalfa, Medicago sativa L.; black mustard, Brassica nigra (L.) Koch; and oat, Avena sativa L.]. Attempts to select germplasm with enhanced suppressive ability have been limited. The second is use of cover crop residues or living mulches to suppress weed growth for variable lengths of time (e.g., winter rye, Secale cereale L.; winter wheat, Triticum aestivum L.; and sorghum). Cover crop residues may selectively provide weed suppression through their physical presence on the soil surface and by release of allelochemics or microbially altered allelochemics. The ability to understand the physiological basis for allelopathy in a crop plant may allow the weed scientist or ecologist to work closely with molecular biologists or traditional plant breeders to selectively enhance the traits responsible for weed suppression.

Report of the Necrology Committee: Weed Science Society of America

Harold Alley, Professor of Merit at the University of Wyoming, died in the summer 1991. He was an extension weed scientist, but he also conducted extensive research in range weed control, especially revegetation of range areas with herbicide and cultural management practices in grazing situations. He was very active in the Western Weed Science Society and was a fellow of WSSA. He also received the WSSA Outstanding Extension Specialists Award. He is survived by his wife Jean and three children.

Biocontrol of Parthenium hysterophorus L.

Parthenium hysterophorus L. (parthenium) is a notorious weed that has caused more concern than any other weed in the recent past, in India, to both the common man and the weed scientist. The common man abhors any contact with parthenium as it is a proven health hazard to sensitized humans and cattle. To the weed scientist, parthenium has proved a challenge because conventional methods have failed to suppress its growth and prevent its unchecked spread.

Plant Problem Diagnosis Field Days — An Approach to Extension Education

Field days on diagnosis of plant problems were conducted by Extension specialists at Michigan State University. The objective was to expose participants to a variety of plant growth problems. Techniques were developed to simulate crop injury from herbicide and fertilizer misapplication and environmental stress. Twenty demonstration plots each were established for corn (Zea maysL.) and soybeans [Glycine max(L.) Merr.]. A specific problem was demonstrated in each plot. Two field days were held in 1985. One field day was conducted for agribusiness personnel and the other for Extension field staff. Promotion of the field days was a cooperative effort among Michigan Cooperative Extension Service, Michigan Pesticide Association, and Michigan Plant Food Council. Resource people conducting tours of the plots and leading discussions of the problems included a weed scientist, a soil fertility specialist, and a crop production agronomist. An evaluation survey indicated that this event was useful in furthering the understanding of plant growth problems. Based on the survey responses, future plant problem diagnosis field days are being planned in Michigan.

Future Role of Weed Science in International Agriculture

Dr. Mercado is Professor, Department of Agronomy, University of the Philippines at Los Baños. Her undergraduate and Master's degrees are from the University of the Phillippines, and her Ph.D. from the University of Iowa. She has been active in weed science since the early 1970's and has trained some 27 M.S. and 8 Ph.D. students. In addition, she and her husband have raised a family of five children. Mercado is a well-recognized weed scientist in her part of the world, having lectured in Indonesia, Thailand, Korea, and Japan. Her weed science textbook, “Introduction to Weed Science,” is widely used in Asian countries. Among her many honors, perhaps those most prized would be three awards for outstanding achievement from her own University of the Philippines.

Who Will do the Research and Teaching?

I would like to start with a premise, then discuss a bit of history as it applies to agriculture and food production, then relate food production to a country's total economy, and lastly, relate the profession of a weed scientist to a country's capacity to produce food.I have enjoyed close and direct association with four different Land Grant Colleges. At the fourth, I served 20 years on the staff and became 50 years of age, giving me the privilege of retiring. If my comments appear critical of Land Grant Colleges as recently administered, these comments are intended to serve as constructive criticism. Contributions of the Land Grant Colleges are basic to our total United States welfare. Our society and our way of life continue to need these contributions. Perhaps the goals and objectives should be changed, but the contributions are still strongly needed.