The biology of Canadian weeds. 138. Kochia scoparia (L.) Schrad.

2009 ◽  
Vol 89 (1) ◽  
pp. 141-167 ◽  
Author(s):  
Lyle F Friesen ◽  
Hugh J Beckie ◽  
Suzanne I Warwick ◽  
Rene C Van Acker

Kochia [Kochia scoparia (L.) Schrad.] is an annual broadleaf weed species native to Eurasia and introduced as an ornamental to the Americas by immigrants in the mid- to late 1800s. Although sometimes categorized in the genus Bassia, there is no compelling reason for this classification. This naturalized species is a common and economically important weed in crop production systems and ruderal areas in semiarid to arid regions of North America, and has expanded northward in the Canadian Prairies during the past 30 yr. Although primarily self-pollinated, substantial pollen-mediated gene flow and efficient seed dispersal aids both short- and long-distance spread. The weed is morphologically highly variable, and its growth and development are markedly affected by environmental conditions. Kochia, a C4 species, is highly competitive in cropping systems because of its ability to germinate at low soil temperatures and emerge early, grow rapidly, tolerate heat, drought and salinity, and exert allelopathic effects on neighboring species. Moreover, herbicidal control has been compromised to some extent by the widespread evolution of herbicide resistance in the species. Kochia is used as a forage, is palatable to livestock with nutritional value similar to that of alfalfa (Medicago sativa), but can be toxic if it comprises the majority of the diet. Although kochia pollen is an allergen, the seed is a source of phytochemicals including mosquito pheromones and saponins that are potentially beneficial to human health; kochia also is beneficial in phytoremediation of soils contaminated by hydrocarbons or pesticides. Key words: Kochia, Kochia scoparia, Bassia scoparia, herbicide resistance, soil salinity tolerance, weed biology

2009 ◽  
Vol 89 (4) ◽  
pp. 775-789 ◽  
Author(s):  
H J Beckie ◽  
A Francis

This account updates that published by Crompton and Bassett in 1985 (classified then as Salsola pestifer A. Nels.). The taxonomy of this species has been controversial and confusing. Salsola tragus is an annual broadleaf weed species native to Eurasia and inadvertently introduced to the Americas in crop seed in 1873. This naturalized species is a common and economically important weed in crop production systems and non-cropped disturbed areas in semiarid to arid regions of western North America; in eastern North America, S. tragus commonly occurs along roadsides, railways, and other dry, stony, and sandy areas. Pollen-mediated gene flow and efficient seed dispersal aids both short- and long-distance spread. As a C4 species, S. tragus is highly competitive in semiarid and arid small-grain cropping systems because of its ability to emerge early, efficiently extract soil available water by its extensive root system, and tolerate heat, drought, and salinity. Moreover, the evolution of acetolactate synthase-inhibitor resistance has impacted herbicidal control of the species. The weed has been used as an emergency forage during drought, and is palatable when immature and non-toxic to livestock. Key words: Salsola tragus, Salsola pestifer, Salsola iberica, Salsola kali, Russian thistle, weed biology


2020 ◽  
Vol 34 (3) ◽  
pp. 431-436
Author(s):  
James T. Brosnan ◽  
Michael W. Barrett ◽  
Prasanta C. Bhowmik

AbstractHerbicide resistance has for decades been an increasing problem of agronomic crops such as corn and soybean. Several weed species have evolved herbicide resistance in turfgrass systems such as golf courses, sports fields, and sod production—particularly biotypes of annual bluegrass and goosegrass. Consequences of herbicide resistance in agronomic cropping systems indicate what could happen in turfgrass if herbicide resistance becomes broader in terms of species, distribution, and mechanisms of action. The turfgrass industry must take action to develop effective resistance management programs while this problem is still relatively small in scope. We propose that lessons learned from a series of national listening sessions conducted by the Herbicide Resistance Education Committee of the Weed Science Society of America to better understand the human dimensions affecting herbicide resistance in crop production provide tremendous insight into what themes to address when developing effective resistance management programs for the turfgrass industry.


1992 ◽  
Vol 6 (3) ◽  
pp. 665-668 ◽  
Author(s):  
Donald L. Wyse

The development of crop cultivars with resistance to selected herbicides has the potential to impact environmental quality, food safety, consumers, and crop producers in either a positive or negative manner. The technology that makes it possible to develop herbicide-resistant crops is neither good nor bad, it is rather how the products of this technology are used that will determine whether or not the introduction of herbicide-resistant crops is ultimately a good or bad decision. The introduction of herbicide-resistant crops will have diverse impacts leading to redundancy, diversity, and confusion in crop production systems. Often the introduction of herbicide-resistant cultivars will have the same impact on cropping systems as the introduction of a new herbicide that has the same mode-of-action and use pattern of herbicides already in use. This may add diversity of herbicide options for a given crop but will cause redundancy of product use over several years. This redundancy could lead to weed resistance and water quality concerns. Confusion at the user level will exist because not all cultivars of a crop will be resistant to the herbicide; this could be the major deterrent to widespread adoption of herbicide-resistant crops. Steps must be taken to provide information to crop producers that will insure that herbicide-resistant crops are used effectively and safely. Weed scientists will determine whether this technology will be used to improve food safety, water quality, crop production systems, and farmer profitability or have a negative impact on agriculture and the whole of society.


2018 ◽  
Vol 32 (4) ◽  
pp. 475-488 ◽  
Author(s):  
Jill Schroeder ◽  
Michael Barrett ◽  
David R. Shaw ◽  
Amy B. Asmus ◽  
Harold Coble ◽  
...  

AbstractHerbicide resistance is ‘wicked’ in nature; therefore, results of the many educational efforts to encourage diversification of weed control practices in the United States have been mixed. It is clear that we do not sufficiently understand the totality of the grassroots obstacles, concerns, challenges, and specific solutions needed for varied crop production systems. Weed management issues and solutions vary with such variables as management styles, regions, cropping systems, and available or affordable technologies. Therefore, to help the weed science community better understand the needs and ideas of those directly dealing with herbicide resistance, seven half-day regional listening sessions were held across the United States between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide resistance management. The major goals of the sessions were to gain an understanding of stakeholders and their goals and concerns related to herbicide resistance management, to become familiar with regional differences, and to identify decision maker needs to address herbicide resistance. The messages shared by listening-session participants could be summarized by six themes: we need new herbicides; there is no need for more regulation; there is a need for more education, especially for others who were not present; diversity is hard; the agricultural economy makes it difficult to make changes; and we are aware of herbicide resistance but are managing it. The authors concluded that more work is needed to bring a community-wide, interdisciplinary approach to understanding the complexity of managing weeds within the context of the whole farm operation and for communicating the need to address herbicide resistance.


2012 ◽  
Vol 26 (3) ◽  
pp. 525-530 ◽  
Author(s):  
Joby M. Prince ◽  
David R. Shaw ◽  
Wade A. Givens ◽  
Micheal D. K. Owen ◽  
Stephen C. Weller ◽  
...  

Almost 1,650 corn, cotton, and soybean growers in 22 states participated in a 2010 telephone survey to determine their attitudes with regard to which weed species were most problematic in glyphosate-resistant (GR) crop production systems for corn, cotton, and soybean. The survey is a follow-up to a previous 2005 to 2006 survey that utilized a smaller set of growers from fewer states. In general, growers continued to estimate weed populations as low and few challenges have been created following adoption of GR cropping systems. Pigweed and foxtail species were dominant overall, whereas other species were more commodity and state specific. Corn, cotton, and soybean growers cited velvetleaf, annual morningglory, and waterhemp, respectively, as predominant weeds. Growers in the South region were more likely to report pigweed and waterhemp (Amaranthus spp.), whereas growers in the East and West reported horseweed. When growers were asked with which GR weeds they had experienced personally, horseweed was reported in all regions, but growers in the South more frequently reported pigweed, whereas growers in the East and West regions more frequently reported waterhemp. Comparisons with the previous 2005 survey indicated that more growers believed they were experiencing GR weeds and were more aware of specific examples in their state. In particular, the Amaranthus complex was of greatest concern in continuously cropped soybean and cotton.


Author(s):  
Daniel P. Roberts ◽  
Nicholas M. Short ◽  
James Sill ◽  
Dilip K. Lakshman ◽  
Xiaojia Hu ◽  
...  

AbstractThe agricultural community is confronted with dual challenges; increasing production of nutritionally dense food and decreasing the impacts of these crop production systems on the land, water, and climate. Control of plant pathogens will figure prominently in meeting these challenges as plant diseases cause significant yield and economic losses to crops responsible for feeding a large portion of the world population. New approaches and technologies to enhance sustainability of crop production systems and, importantly, plant disease control need to be developed and adopted. By leveraging advanced geoinformatic techniques, advances in computing and sensing infrastructure (e.g., cloud-based, big data-driven applications) will aid in the monitoring and management of pesticides and biologicals, such as cover crops and beneficial microbes, to reduce the impact of plant disease control and cropping systems on the environment. This includes geospatial tools being developed to aid the farmer in managing cropping system and disease management strategies that are more sustainable but increasingly complex. Geoinformatics and cloud-based, big data-driven applications are also being enlisted to speed up crop germplasm improvement; crop germplasm that has enhanced tolerance to pathogens and abiotic stress and is in tune with different cropping systems and environmental conditions is needed. Finally, advanced geoinformatic techniques and advances in computing infrastructure allow a more collaborative framework amongst scientists, policymakers, and the agricultural community to speed the development, transfer, and adoption of these sustainable technologies.


2017 ◽  
Vol 32 (2) ◽  
pp. 103-108 ◽  
Author(s):  
Michael J. Walsh ◽  
John C. Broster ◽  
Stephen B. Powles

AbstractIn Australia, widespread evolution of multi-resistant weed populations has driven the development and adoption of harvest weed seed control (HWSC). However, due to incompatibility of commonly used HWSC systems with highly productive conservation cropping systems, better HWSC systems are in demand. This study aimed to evaluate the efficacy of the integrated Harrington Seed Destructor (iHSD) mill on the seeds of Australia’s major crop weeds during wheat chaff processing. Also examined were the impacts of chaff type and moisture content on weed seed destruction efficacy. Initially, the iHSD mill speed of 3,000 rpm was identified as the most effective at destroying rigid ryegrass seeds present in wheat chaff. Subsequent testing determined that the iHSD mill was highly effective (>95% seed kill) on all Australian crop weeds examined. Rigid ryegrass seed kill was found to be highest for lupin chaff and lowest in barley, with wheat and canola chaff intermediate. Similarly, wheat chaff moisture reduced rigid ryegrass seed kill when moisture level exceeded 12%. The broad potential of the iHSD mill was evident, in that the reductions in efficacy due to wide-ranging differences in chaff type and moisture content were relatively small (≤10%). The results from these studies confirm the high efficacy and widespread suitability of the iHSD for use in Australian crop production systems. Additionally, as this system allows the conservation of all harvest residues, it is the best HWSC technique for conservation cropping systems.


1990 ◽  
Vol 4 (3) ◽  
pp. 631-634 ◽  
Author(s):  
R. E. Blackshaw

Field studies were conducted in 1987, 1988, and 1989 at Lethbridge, Alberta to determine suitable herbicides for the control of Russian thistle and kochia in field corn grown in a dryland cropping system. Soil-applied atrazine or cyanazine provided inconsistent control of these weeds under dryland conditions. Combining inter-row tillage or 2,4-D applied postemergence with soil-applied atrazine improved the consistency of weed control over years. Postemergence atrazine and dicamba plus 2,4-D controlled Russian thistle and kochia in all years. Corn yields reflected the level of weed control attained with each treatment. The suitability of the various treatments for weed control in corn grown under dryland crop production systems is discussed.


2012 ◽  
Vol 52 (4) ◽  
pp. 486-493 ◽  
Author(s):  
Beata Feledyn-Szewczyk

Abstract The research was conducted from 2008 to 2010, and compared the influence of different weed control methods used in spring wheat on the structure of the weed communities and the crop yield. The study was carried out at the Experimental Station of the Institute of Soil Science and Plant Cultivation - State Research Institute in Osiny as part of a long-term trial where these crop production systems had been compared since 1994. In the conventional and integrated systems, spring wheat was grown in a pure stand, whereas in the organic system, the wheat was grown with undersown clover and grasses. In the conventional system, herbicides were applied two times in a growing season, but in the integrated system - only once. The effectiveness of weed management was lower in the organic system than in other systems, but the dry matter of weeds did not exceed 60 g/m2. In the integrated system, the average dry matter of weeds in spring wheat was 4 times lower, and in the conventional system 10 times lower than in the organic system. Weed diversity was the largest in spring wheat cultivated in the organic system. In the conventional and integrated systems, compensation of some weed species was observed (Viola arvensis, Fallopia convolvulus, Equisetum arvense). The comparison of weed communities using Sorenson’s indices revealed more of a similarity between systems in terms of number of weed species than in the number of individuals. Such results imply that qualitative changes are slower than quantitative ones. The yield of grain was the biggest in the integrated system (5.5 t/ha of average). It was 35% higher than in the organic system, and 20% higher than in conventional ones.


2013 ◽  
Vol 27 (4) ◽  
pp. 656-663 ◽  
Author(s):  
Kristin K. Rosenbaum ◽  
Kevin W. Bradley

A survey of soybean fields containing waterhemp infestations was conducted just prior to harvest in 2008 and 2009 to determine the frequency and distribution of glyphosate-resistant waterhemp in Missouri, and to determine if there are any in-field parameters that may serve as indicators of glyphosate resistance in this species in future crop production systems. Glyphosate resistance was confirmed in 99 out of 144, or 69%, of the total waterhemp populations sampled, which occurred in 41 counties of Missouri. Populations of glyphosate-resistant waterhemp were more likely to occur in fields with no other weed species present at the end of the season, continuous cropping of soybean, exclusive use of glyphosate for several consecutive seasons, and waterhemp plants showing obvious signs of surviving herbicide treatment compared to fields characterized with glyphosate-susceptible waterhemp. Therefore, it is suggested that these four site parameters, and certain combinations of these parameters, serve as predictors of glyphosate resistance in future waterhemp populations.


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