Glyphosate-Resistant Horseweed (Conyza canadensis) Dose Response to Saflufenacil, Saflufenacil plus Glyphosate, and Metribuzin plus Saflufenacil plus Glyphosate in Soybean

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 727-734 ◽  
Author(s):  
Christopher M. Budd ◽  
Nader Soltani ◽  
Darren E. Robinson ◽  
David C. Hooker ◽  
Robert T. Miller ◽  
...  
Keyword(s):  
Dose Response ◽  
Weed Management ◽  
Mode Of Action ◽  
Management Strategy ◽  
Effective Rate ◽  
Conyza Canadensis ◽  
No Till ◽  
Herbicide Mixture

The control of glyphosate-resistant (GR) horseweed (Conyza canadensis) in soybean has been variable with glyphosate plus saflufenacil. The objective of this research was to determine the biologically effective rate (BER) of saflufenacil, saflufenacil mixed with glyphosate, and metribuzin mixed with saflufenacil and glyphosate applied preplant (PP) for the control of GR horseweed in no-till soybean; a study was conducted to determine each of the three treatments. For each study, seven field sites infested with GR horseweed were used over a 2-yr period (2014, 2015). Saflufenacil alone at 25 and 36 g ai ha–1 provided 90 and 95% control of GR Horseweed 8 wk after application, while the BER to achieve 98% control was outside of the treatment range tested. The saflufenacil plus glyphosate (900 g ai ha–1) BER experiment found less saflufenacil was required as 25, 34, and 47 g ha–1 provided 90, 95, and 98% control of GR horseweed respectively. The metribuzin BER experiment found 61, 261, and 572 g ha–1 was required to provide 90, 95 and 98% control of GR horseweed, respectively, mixed with saflufenacil (25 g ha–1) and glyphosate (900 g ha–1). The addition of metribuzin with the recommended rate of saflufenacil (25 g ha–1) plus glyphosate improved control and a second effective herbicide mode of action for the control of GR horseweed. The use of a threeway herbicide mixture can be an effective weed management strategy to control GR horseweed in soybean.

Changes in Herbicide Use Patterns and Production Practices Resulting from Glyphosate-Resistant Crops

2006 ◽  
Vol 20 (2) ◽  
pp. 301-307 ◽  
Author(s):  
Bryan G. Young
Keyword(s):  
Weed Management ◽  
Management Strategy ◽  
Crop Production ◽  
Large Scale ◽  
Resistance Management ◽  
Use Patterns ◽  
No Till ◽  
Production Practices ◽  
Sites Of Action ◽  
Herbicide Use

Recent shifts in herbicide use patterns can be attributed to rapid, large-scale adoption of glyphosate-resistant soybean and cotton. A dramatic increase in glyphosate use is the most obvious change associated with the adoption of glyphosate-resistant crops. Consequently, the diversity of herbicides used for weed management in these crops has declined, particularly in soybean. To date, the availability of glyphosate-resistant corn has limited the use of glyphosate in corn. While exploiting the benefits of glyphosate-resistant crops, many growers have abandoned the principles of sound weed and herbicide-resistance management. Instead of incorporating glyphosate into a resistance management strategy utilizing multiple herbicide sites of action, many growers rely exclusively upon glyphosate for weed control. Although it is difficult to establish a clear relationship between the adoption of glyphosate-resistant crops and changes in other crop production practices, the increase in no-till and strip-till production of cotton and soybean between 1995 and 2002 may have been facilitated by glyphosate-resistant crops.

An integrated weed management strategy for the control of horseweed (Conyza canadensis)

Weed Science ◽  
2020 ◽  
pp. 1-41
Author(s):  
Theodore R. Vanhie ◽  
François J. Tardif ◽  
Peter Smith ◽  
Saeed Vazan ◽  
Michael Cowbrough ◽  
...  
Keyword(s):  
Root Development ◽  
Weed Management ◽  
Management Strategy ◽  
Management Strategies ◽  
Integrated Weed Management ◽  
Conyza Canadensis ◽  
Seedling Height ◽  
Selection Pressures ◽  
Cereal Rye ◽  
Allelopathic Compound

Abstract Multiple herbicide-resistant populations of horseweed [Conyza canadensis (L.) Cronquist] continue to spread rapidly throughout Ontario, notably in areas where no-till soybean [Glycine max (L.) Merr.] are grown. The occurrence of multiple herbicide resistance within these populations suggests that the future role of herbicide tank mixtures as a means of control will be limited. An integrated weed management strategy utilizing complementary selection pressures is needed to reduce the selection intensity of relying solely on herbicides for control. Field studies were conducted in 2018 and 2019 to test the hypothesis if fall-seeded cereal rye (Secale cereale L.) can reduce C. canadensis seedling density and suppress seedling growth, then the interaction(s) of complementary selection pressures of tillage, cereal rye and herbicides would improve the level of C. canadensis control. Laboratory studies were conducted to determine if the allelopathic compound BOA affected the root development of C. canadensis seedlings. The interactions observed among multiple selection pressures of tillage, cereal rye and herbicides were inconsistent between the two years of study. A monoculture of cereal rye seeded in the fall, however, did reduce seedling height and biomass of C. canadensis consistently but not density. This reduction in seedling height and biomass was likely caused by the allelopathic compound BOA, which reduced seedling root development. Control of C. canadensis seedlings in the spring required the higher registered rates of dicamba or saflufenacil. The addition of shallow fall tillage and the presence of cereal rye did not improve the variability in control observed notably with 2,4-D or the lower rates of saflufenacil or dicamba. With the implementation of complementary weed management strategies, environmental variables in any given year will likely have a direct influence on whether these interactions are additive or synergistic.

Response and Survival of Rosette-Stage Horseweed (Conyza canadensis) after Exposure to 2,4-D

Weed Science ◽  
2008 ◽  
Vol 56 (5) ◽  
pp. 748-752 ◽  
Author(s):  
Greg R. Kruger ◽  
Vince M. Davis ◽  
Stephen C. Weller ◽  
William G. Johnson
Keyword(s):  
Dose Response ◽  
Growth Suppression ◽  
Conyza Canadensis ◽  
Visible Injury ◽  
Susceptible Population ◽  
Soybean Production ◽  
No Till ◽  
Dose Response Study

2,4-D is often used as a preplant burndown herbicide to help control horseweed and other broadleaf weeds before planting in no-till corn and soybean production. Isolated instances of poor horseweed control have occurred in production fields. The objective of this research was to evaluate the response of various horseweed populations to 2,4-D. In the first study, 478 horseweed populations from Indiana were subjected to 280 g ae ha−1of 2,4-D amine in the greenhouse. This rate of 2,4-D caused visible injury and prevented all biotypes from forming new leaves for 28 days. There were specific populations where all plants sprayed were alive at 28 days after treatment (DAT), and approximately 10% of all populations had a least one plant that survived 280 g ae ha−12,4-D, resumed growth, and produced seed. In a dose-response study, we observed populations with three-fold more tolerance to 2,4-D. The most tolerant population had a GR90of 513 g ae ha−1and the most susceptible population had a GR90of 121 g ae ha−1based on dry weights. Growth suppression with 2,4-D was not affected by rosette size for rosettes between 0.5 and 10 cm in width.

Preplant followed by postemergence herbicide programs and biologically effective rate of metribuzin for control of glyphosate-resistant common ragweed (Ambrosia artemisiifolia) in soybean

2018 ◽  
Vol 98 (4) ◽  
pp. 809-814 ◽  
Author(s):  
Holly P. Byker ◽  
Annemarie C. Van Wely ◽  
Amit J. Jhala ◽  
Nader Soltani ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Weed Management ◽  
Aboveground Biomass ◽  
Mode Of Action ◽  
Cropping Systems ◽  
Effective Rate ◽  
Ambrosia Artemisiifolia ◽  
Common Ragweed ◽  
Preliminary Research ◽  
Herbicide Programs

With no new herbicides with a novel mode of action in the marketplace in corn–soybean cropping systems, control of glyphosate-resistant (GR) weeds requires the re-evaluation of existing herbicides. This necessitates a renewed focus on using herbicide tank-mixes and sequential herbicide programs while also striving to minimize the environmental impact of weed management. Preliminary research identified four preplant (PP) herbicides (2,4-D, saflufenacil/dimethenamid-P, linuron, and metribuzin) and one postemergence (POST) herbicide (fomesafen) that provided good but inconsistent control of GR common ragweed when applied alone in soybean. The objectives of this study were to determine the biologically effective rate of metribuzin and evaluate PP followed by POST herbicide programs for control of GR common ragweed in soybean. The aforementioned PP herbicides reduced GR common ragweed density and aboveground biomass by 82%–94% and 55%–89%, respectively. In contrast, a PP herbicide followed by fomesafen applied POST decreased common ragweed densities and aboveground biomass by 97%–99% and 93%–98%, respectively. Metribuzin applied at 824 and 1015 g a.i. ha−1 controlled GR common ragweed 90% at 4 and 8 wk after application, respectively. This study concludes that GR common ragweed can be controlled with a PP followed by POST herbicide program and metribuzin has potential for control of GR common ragweed in soybean.

scholarly journals Integrated weed management with reduced herbicides in a no‐till dairy rotation

2021 ◽  
Author(s):  
Haleigh Summers ◽  
Heather D. Karsten ◽  
William Curran ◽  
Glenna M. Malcolm
Keyword(s):  
Weed Management ◽  
Integrated Weed Management ◽  
No Till

Fall and Spring Preplant Herbicide Applications Influence Spring Emergence of Glyphosate-Resistant Horseweed (Conyza canadensis)

2010 ◽  
Vol 24 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Vince M. Davis ◽  
Greg R. Kruger ◽  
Bryan G. Young ◽  
William G. Johnson
Keyword(s):  
Early Spring ◽  
Late Spring ◽  
Conyza Canadensis ◽  
No Till ◽  
Early Fall ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds ◽  
Spring Emergence ◽  
Residual Control

Horseweed (Conyza canadensis) is a common weed in no-till crop production systems. It is problematic because of the frequent occurrence of biotypes resistant to glyphosate and acetolactate synthase (ALS)-inhibiting herbicides and its ability to complete its life cycle as a winter or summer annual weed. Tactics to control horseweed while controlling other winter annual weeds routinely fail; herbicide application timing and spring emergence patterns of horseweed may be responsible. The objectives of this experiment were to (1) determine the influence of fall and spring herbicides with and without soil residual horseweed activity on spring-emerging glyphosate-resistant (GR) horseweed density and (2) evaluate the efficacy and persistence of saflufenacil on GR horseweed. Field studies were conducted in southern Indiana and Illinois from fall 2006 to summer 2007 and repeated in 2007 to 2008. Six preplant herbicide treatments were applied at four application timings: early fall, late fall, early spring, and late spring. Horseweed plants were counted every 2 wk following the first spring application until the first week of July. Horseweed almost exclusively emerged in the spring at both locations. Spring horseweed emergence was higher when 2,4-D + glyphosate was fall-applied and controlled other winter annual weeds. With fall-applied 2,4-D + glyphosate, over 90% of the peak horseweed density was observed before April 25. In contrast, only 25% of the peak horseweed density was observed in the untreated check by April 25. Starting from the initiation of horseweed emergence in late March, chlorimuron + tribenuron applied early fall or early spring, and spring-applied saflufenacil at 100 g ai/ha provided greater than 90% horseweed control for 12 wk. Early spring–applied saflufenacil at 50 g ai/ha provided 8 wk of greater than 90% residual control, and early spring–applied simazine provided 6 wk of greater than 90% control. When applied in late spring, saflufenacil was the only herbicide treatment that reduced horseweed densities by greater than 90% compared to 2,4-D + glyphosate. We concluded from this research that fall applications of nonresidual herbicides can increase the rate and density of spring emerging horseweed. In addition, spring-applied saflufenacil provides no-till producers with a new preplant herbicide for foliar and residual control of glyphosate- and ALS-resistant horseweed.

Influence of Weed Management Practices and Crop Rotation on Glyphosate-Resistant Horseweed (Conyza canadensis) Population Dynamics and Crop Yield-Years III and IV

Weed Science ◽  
2009 ◽  
Vol 57 (4) ◽  
pp. 417-426 ◽  
Author(s):  
Vince M. Davis ◽  
Kevin D. Gibson ◽  
Thomas T. Bauman ◽  
Stephen C. Weller ◽  
William G. Johnson
Keyword(s):  
Population Dynamics ◽  
Crop Rotation ◽  
Crop Yield ◽  
Cover Crops ◽  
Weed Management ◽  
Management Practices ◽  
Plant Density ◽  
Crop Yields ◽  
Management Systems ◽  
No Till

Horseweed is an increasingly common and problematic weed in no-till soybean production in the eastern cornbelt due to the frequent occurrence of biotypes resistant to glyphosate. The objective of this study was to determine the influence of crop rotation, winter wheat cover crops (WWCC), residual non-glyphosate herbicides, and preplant application timing on the population dynamics of glyphosate-resistant (GR) horseweed and crop yield. A field study was conducted from 2003 to 2007 in a no-till field located at a site that contained a moderate infestation of GR horseweed (approximately 1 plant m−2). The experiment was a split-plot design with crop rotation (soybean–corn or soybean–soybean) as main plots and management systems as subplots. Management systems were evaluated by quantifying in-field horseweed plant density, seedbank density, and crop yield. Horseweed densities were collected at the time of postemergence applications, 1 mo after postemergence (MAP) applications, and at the time of crop harvest or 4 MAP. Viable seedbank densities were also evaluated from soil samples collected in the fall following seed rain. Soybean–corn crop rotation reduced in-field and seedbank horseweed densities vs. continuous soybean in the third and fourth yr of this experiment. Preplant herbicides applied in the spring were more effective at reducing horseweed plant densities than when applied in the previous fall. Spring-applied, residual herbicide systems were the most effective at reducing season-long in-field horseweed densities and protecting crop yields since the growth habit of horseweed in this region is primarily as a summer annual. Management systems also influenced the GR and glyphosate-susceptible (GS) biotype population structure after 4 yr of management. The most dramatic shift was from the initial GR : GS ratio of 3 : 1 to a ratio of 1 : 6 after 4 yr of residual preplant herbicide use followed by non-glyphosate postemergence herbicides.

scholarly journals Weed Management Potentials of Identified Invasive Weed Species

2015 ◽  
Vol 22 (1) ◽  
Author(s):  
Annabella T. Carcusia ◽  
Pet Roey L. Pascual ◽  
James Francienne J. Rosit
Keyword(s):  
Weed Management ◽  
Germination Rate ◽  
Cyperus Rotundus ◽  
Conyza Canadensis ◽  
Mimosa Pudica ◽  
Chromolaena Odorata ◽  
Weed Species ◽  
Invasive Weed ◽  
Percent Germination ◽  
Percent Mortality

Synthetic herbicide, the most popular weed control, causes environmental hazards. The use of allelopathy in controlling weeds is a possible alternative for sustainable weed management. The study was conducted to determine the allelopathic potentials of identified invasive weed species in terms of percent and rate of germination, plant height, length of leaves and roots and percent mortality of grasses, sedges, and broadleaves. The treatments were: T0-Pre/Post-emergence Herbicide, T1Tap Water, T2-Mimosa pudica extract,T3-Lantana camara extract,T4-Chromolaena odorata extract. These were compared according to their effects on Cenchrus spinifex, Conyza canadensis, Impatiens wallerana and Cyperus rotundus. Data were analyzed using Analysis of Variance (ANOVA) for Completely Randomized Design. A further test was done using Duncans Multiple Range Test (DMRT). For germination, Lantana camara is effective in reducing the percent germination and prolonging germination rate of most common weed species. On the other hand, Chromolaena odorata is effective in reducing the percent germination and prolonging the germination rate of Impatiens wallerana, while Mimosa pudica was effective against Cenchrus spinifex and Cyperus rotundus. For growth and development, Mimosa pudica was found to be the most effective in all common weed species, except for Cyperus rotundus where Chromolaena odorata was most effective on reducing the length of leaves and roots, and above ground fresh weight. Furthermore, Chromolaena odorata was found effective against both Cyperus rotundus and Conyza canadensis while Mimosa pudica was effective against Cenchrus spinifex in terms of percent mortality. Thus, such potential of invasive weed species for weed management should be utilized. 

Sumatran Fleabane (Erigeron sumatrensis) Resistant to PSI-Inhibitor Herbicides and Physiological Responses to Paraquat

Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Jéssica F. L. Leal ◽  
Amanda dos S. Souza ◽  
Junior Borella ◽  
André Lucas S. Araujo ◽  
Ana Claudia Langaro ◽  
...  
Keyword(s):  
Dose Response ◽  
Weed Management ◽  
Crop Production ◽  
Antioxidant Enzyme Activities ◽  
Multiple Resistance ◽  
Fast Recovery ◽  
Continuous Growth ◽  
Herbicide Resistant ◽  
Paraquat Resistance ◽  
Resistance To Herbicides

Abstract Herbicide-resistant weed management is one of the greatest agricultural challenges in crop production. Thus, the quick identification of resistant-herbicide weeds is extremely important for management. This study aimed to evaluate resistance to PSI-inhibitor herbicides (diquat) of Sumatran Fleabane [(Erigeron sumatrensis (Retz.) E.Walker)] and physiological response to paraquat application. The research was conducted with two E. sumatrensis biotypes, one susceptible and the other with multiple resistance to herbicides from five different modes of action (glyphosate, paraquat, diuron, saflufenacil, and 2,4-D). A dose-response assay was carried out to evaluate herbicide resistance to diquat in paraquat-resistant E. sumatrensis biotype. The enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), hydrogen peroxide (H2O2) content, and chlorophyll a fluorescence were measured in both biotypes after paraquat (400 g ai ha−1) application. The dose-response assay confirmed resistance of E. sumatrensis to diquat with resistance factor levels of 26-fold and 6-fold for LD50 and GR50 values, respectively, compared with the susceptible biotype. The accumulation of H2O2 occurred faster in the paraquat-susceptible biotype than in the resistant ones. Paraquat treatment caused an increase in SOD and APX activity in the susceptible biotype, but antioxidant enzyme activities were unaffected by paraquat in the resistant one at 5 hours after application (HAA). Chlorophyll a fluorescence increased along the first 4 HAA in both resistant and susceptible biotypes. However, at 24 HAA the resistant biotype showed a decline in fluorescence close to untreated plants while susceptible one died, which can be used to diagnose paraquat resistance at 24 HAA. There is confirmed resistance to diquat in a paraquat-resistant E. sumatrensis biotype. The paraquat-resistant biotype does not induce antioxidative enzymes, as a possible mechanism of resistance to paraquat, but shows a fast recovery of photosynthesis and continuous growth when subjected to paraquat, while the paraquat-susceptible biotype does not survive.

Weeds, nitrogen and yield: measuring the effectiveness of an organic cover cropped vegetable no-till system

2018 ◽  
Vol 34 (5) ◽  
pp. 439-446 ◽  
Author(s):  
David Robb ◽  
Geoff Zehnder ◽  
Robin Kloot ◽  
William Bridges ◽  
Dara Park
Keyword(s):  
Cover Crops ◽  
Weed Management ◽  
Field Experiments ◽  
Soil Health ◽  
Soil Disturbance ◽  
Weed Suppression ◽  
Vegetable Production ◽  
Soil N ◽  
No Till ◽  
Mechanical Methods

AbstractOrganic vegetable growers rely heavily on mechanical methods such as tillage and other forms of labor-intensive soil cultivation for weed management despite the negative effects to soil health associated with intensive soil disturbance. The use of cover crops and no-till (NT) vegetable production represents an alternative approach to weed control that can enhance rather than degrade soil health; however, there are challenges inherent with this practice and previous results in vegetable production have been mixed. Field experiments were conducted over 2 yr at the Clemson Student Organic Farm to examine the effects of tillage [NT versus conventional tillage (CT)] on weed development and management in organic tomato and summer squash production under different nitrogen (N) fertility regimes, and to assess soil N dynamics in both systems. Squash yields were similar between tillage treatments in both years. NT tomato yields were 43% greater than CT yields in 2014, whereas CT tomato yields were 46% greater than NT yields in 2015. Squash and tomato yields per unit of management labor (time) were significantly greater in NT compared with CT treatments for both years. There were no statistical differences in squash and tomato yields between N fertilization treatments in either year. Pre- and post-season soil N results were mixed. Pre-season soil N levels were significantly higher in NT tomato plots in 2014 but similar between tillage treatments in tomato plots in 2015 and in squash plots both years. Post-season soil N levels in tomato plots were similar between tillage treatments both years. Post-season soil N levels were significantly higher in NT squash plots in 2014 and in CT squash plots in 2015. Roller-crimped NT mulches provided adequate early-season weed suppression in both years and saved considerable weed management and seedbed preparation labor. Overall, the results demonstrated that organic NT is a viable method for reduced tillage summer vegetable production in the southeastern Piedmont region.

Sign in / Sign up

Export Citation Format

Share Document