scholarly journals Environmental cues affecting horseweed (Conyza canadensis) growth type and their sensitivity to glyphosate

Weed Science ◽  
2021 ◽  
pp. 1-35
Author(s):  
John A. Schramski ◽  
Christy L. Sprague ◽  
Eric L. Patterson
Keyword(s):  
Soil Moisture ◽  
Glyphosate Resistance ◽  
Single Parent ◽  
Environmental Cues ◽  
Conyza Canadensis ◽  
Growth Type ◽  
Susceptible Population ◽  
Water Imbibition ◽  
Growth Types ◽  
Winter Annual

Abstract Horseweed [Conyza canadensis (L.) Cronquist] is a facultative winter annual weed that can emerge from March to November in Michigan. Fall emerging C. canadensis overwinters as a rosette, while spring emerging C. canadensis skips the rosette stage and immediately grows upright upon emergence. In Michigan, primary emergence recently shifted from fall to spring/summer and therefore from a rosette to an upright growth type. Growth chamber experiments were conducted to determine 1) whether both C. canadensis growth types could originate from a single parent and 2) if common environmental cues can influence growth type. Variations in temperature, photoperiod, competition, shading, and soil moisture only resulted in the rosette growth type in four C. canadensis populations originating from seed collected from a single parent of the upright growth type. However, a vernalization period of four weeks following water imbibition, but prior to germination, resulted in the upright growth type. Dose-response experiments were conducted to determine whether glyphosate sensitivity differed between C. canadensis growth types generated from a single parent of the upright growth type. Upright type C. canadensis from known glyphosate-resistant populations ISB-18 and MSU-18 were four and three-fold less sensitive to glyphosate than their rosette siblings, respectively. Interestingly, differences in glyphosate sensitivity was not observed between growth types from the susceptible population. These results suggest that while C. canadensis populations shift from winter to summer annual lifecycles, concurrent increases in glyphosate resistance could occur.

Glyphosate-Resistant Horseweed (Conyza canadensis) Control with Dicamba in Alabama

2015 ◽  
Vol 29 (4) ◽  
pp. 633-640 ◽  
Author(s):  
Michael L. Flessner ◽  
J. Scott McElroy ◽  
James D. McCurdy ◽  
Jordan M. Toombs ◽  
Glenn R. Wehtje ◽  
...  
Keyword(s):  
Growth Stage ◽  
Resistance Management ◽  
Population Data ◽  
Glyphosate Resistance ◽  
Data Type ◽  
Growth Stages ◽  
Conyza Canadensis ◽  
Susceptible Population ◽  
Resistance Evaluation ◽  
Treatment Research

The development and spread of glyphosate-resistant (GR) horseweed has increased the use of dicamba as an alternative herbicide treatment. Research evaluated suspected glyphosate-resistant horseweed populations from DeKalb (GR-1) and Cherokee (GR-2) counties, Alabama, for response to glyphosate, dicamba, and glyphosate + dicamba. Populations used for resistance determination were tested at rosette and bolt growth stages. Glyphosate resistance evaluation treatments ranged from 0 to 36.0 kg ae ha−1. Data confirmed that GR-1 and GR-2 horseweed populations were 3.0 to 38 times more resistant to glyphosate than the susceptible population, according to population, data type, and growth stage at treatment. GR-1 and GR-2 populations were further evaluated for response to dicamba. Dicamba was applied at 0 to 1.12 kg ai ha−1, both with and without the addition of glyphosate at 1.12 kg ae ha−1. All populations had similar tolerance to dicamba, with the exception of GR-2 treated at the rosette growth stage, which had ~2-fold greater tolerance. When glyphosate was tank-mixed with dicamba, the response of GR populations was similar to that of dicamba alone. Therefore, any potential resistance-management benefit of tank-mixing dicamba with glyphosate may be negated when one is attempting to control GR horseweed. Conversely, adding glyphosate to dicamba drastically enhanced control of the susceptible population at both growth stages.

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.

scholarly journals Ruderal succession starting at different seasons

2014 ◽  
Vol 55 (3) ◽  
pp. 403-419 ◽  
Author(s):  
Reinhard Bornkamm
Keyword(s):  
Poa Pratensis ◽  
Floristic Composition ◽  
Clayey Loam ◽  
First Year ◽  
Conyza Canadensis ◽  
Senecio Vulgaris ◽  
Different Seasons ◽  
Winter Annual ◽  
Second Year ◽  
Different Soils

Succession experiments were carried out in 1 m<sup>2</sup> sized plots on three different soils (S = sand. SCL = silty clayey loam, CL = clayey loam). Vegetation was allowed to grow for 9 years, starting at different dates between 18.06.1969 and 1.04.1971. The greatest part of the variation of floristic composition and cover was brought about by the different soils. Direct effects of the starting season were detected only in the first two years. On sand in the first year the winter annual <em>Conyza canadensis</em> was well developed on the plots that had started in spring, but was poorly developed on the summer and fall plots. In the second year it decreased in the spring plots but increased in the summer and fall plots. The same was true for the winter annual <em>Sonchus asper</em> on CL. On SCL, however., <em>Senecio vulgaris</em>, belonging to the therophyta epeteia (overwintering in summer habit), was well developed in both the spring and summer plots, and showed an increase towards the second year in the fall plots only. In the later years of the experiment plots that had been started early in the year mostly were dominated by <em>Poa pratensis</em> ssp. <em>angustifolia (or Quercus rubra)</em>, whereas plots that had been started late in the year mostly were dominated by <em>Solidagn canadensis</em> together with <em>Artemsia vulgaris</em>. The analyses of the transition events between the (sub)dominant species showed a variety of replacement patterns, but no determinated series of species following each other. It remains, therefore, unclear in what manner the differentiation between the terminal dominants may be related to the starting season.

Functional Genomics Analysis of Horseweed (Conyza canadensis) with Special Reference to the Evolution of Non–Target-Site Glyphosate Resistance

Weed Science ◽  
2010 ◽  
Vol 58 (2) ◽  
pp. 109-117 ◽  
Author(s):  
Joshua S. Yuan ◽  
Laura L. G. Abercrombie ◽  
Yongwei Cao ◽  
Matthew D. Halfhill ◽  
Xin Zhou ◽  
...  
Keyword(s):  
Functional Genomics ◽  
Molecular Mechanisms ◽  
Glyphosate Resistance ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Environmentally Benign ◽  
Conyza Canadensis ◽  
Target Site Resistance ◽  
Weedy Species ◽  
Heterologous Microarray

The evolution of glyphosate resistance in weedy species places an environmentally benign herbicide in peril. The first report of a dicot plant with evolved glyphosate resistance was horseweed, which occurred in 2001. Since then, several species have evolved glyphosate resistance and genomic information about nontarget resistance mechanisms in any of them ranges from none to little. Here, we report a study combining iGentifier transcriptome analysis, cDNA sequencing, and a heterologous microarray analysis to explore potential molecular and transcriptomic mechanisms of nontarget glyphosate resistance of horseweed. The results indicate that similar molecular mechanisms might exist for nontarget herbicide resistance across multiple resistant plants from different locations, even though resistance among these resistant plants likely evolved independently and available evidence suggests resistance has evolved at least four separate times. In addition, both the microarray and sequence analyses identified non–target-site resistance candidate genes for follow-on functional genomics analysis.

scholarly journals New Case of False-Star-Grass (Chloris distichophylla) Population Evolving Glyphosate Resistance

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 377 ◽  
Author(s):  
José G. Vázquez-García ◽  
Sajedeh Golmohammadzadeh ◽  
Candelario Palma-Bautista ◽  
Antonia M. Rojano-Delgado ◽  
José A. Domínguez-Valenzuela ◽  
...  
Keyword(s):  
Weed Management ◽  
Chemical Control ◽  
Shikimic Acid ◽  
Dry Weight ◽  
Glyphosate Resistance ◽  
Integrated Weed Management ◽  
Resistance Level ◽  
Susceptible Population ◽  
First Case

Chloris distichophylla, suspected of glyphosate resistance (GR), was collected from areas of soybean cultivation in Rio Grande do Sul, Brazil. A comparison was made with a susceptible population (GS) to evaluate the resistance level, mechanisms involved, and control alternatives. Glyphosate doses required to reduce the dry weight (GR50) or cause a mortality rate of 50% (LD50) were around 5.1–3 times greater in the GR population than in the GS population. The shikimic acid accumulation was around 6.2-fold greater in GS plants than in GR plants. No metabolized glyphosate was found in either GR or GS plants. Both populations did not differ in the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) basal activity or in vitro inhibition of EPSPS activity by glyphosate (I50). The maximum glyphosate absorption was observed at 96 hours after treatment (HAT), which was twofold higher in the GS plants than in the GR plants. This confirms the first case of glyphosate resistance in C. distichophylla. In addition, at 96 HAT, the GS plants translocated more 14C-glyphosate than the GR ones. The best options for the chemical control of both C. distichophylla populations were clethodim, quizalofop, paraquat, glufosinate, tembotrione, diuron, and atrazine. The first case of glyphosate resistance in C. distichophylla was due to impaired uptake and translocation. Chemical control using multiple herbicides with different modes of action (MOA) could be a tool used for integrated weed management (IWM) programs.

Transformation and segregation of GFP fluorescence and glyphosate resistance in horseweed (Conyza canadensis) hybrids

2006 ◽  
Vol 26 (3) ◽  
pp. 303-311 ◽  
Author(s):  
Matthew D. Halfhill ◽  
Laura L. Good ◽  
Chhandak Basu ◽  
Jason Burris ◽  
Christopher L. Main ◽  
...  
Keyword(s):  
Glyphosate Resistance ◽  
Conyza Canadensis ◽  
Gfp Fluorescence

Field Presence of Glyphosate-Resistant Horseweed (Conyza Canadensis), Common Lambsquarters (Chenopodium Album), and Giant Ragweed (Ambrosia Trifida) Biotypes with Elevated Tolerance to Glyphosate

2008 ◽  
Vol 22 (3) ◽  
pp. 544-548 ◽  
Author(s):  
Andrew M. Westhoven ◽  
Vince M. Davis ◽  
Kevin D. Gibson ◽  
Stephen C. Weller ◽  
William G. Johnson
Keyword(s):  
Chenopodium Album ◽  
Glyphosate Resistance ◽  
Conyza Canadensis ◽  
Glyphosate Tolerance ◽  
Ambrosia Trifida ◽  
Field Surveys ◽  
Common Lambsquarters ◽  
Late Season ◽  
Giant Ragweed ◽  
Different Types

Late-season field surveys conducted in Indiana from 2003 to 2005 showed that common lambsquarters and giant ragweed plants were present in 11 and 22%, respectively, of randomly sampled soybean fields that also contained glyphosate-resistant horseweed. In the fall of 2005 and 2006, seed from 13 common lambsquarters and 22 giant ragweed populations were collected from previously surveyed fields that had confirmed glyphosate-sensitive or -resistant horseweed. The objective of this study was to determine whether the presence of glyphosate-resistant horseweed was correlated with the presence of common lambsquarters and giant ragweed biotypes with elevated tolerance to glyphosate. Through a series of greenhouse screens, 57% of common lambsquarters and 31% of giant ragweed populations collected from fields that had glyphosate-resistant horseweed expressed elevated levels of glyphosate tolerance. However, elevated tolerance to glyphosate was expressed by 33% of giant ragweed and 100% of common lambsquarters populations collected in fields that had glyphosate-sensitive horseweed. Therefore, under the parameters of this experiment and through different types of analyses, we concluded there was not a strong correlation between the late-season presence of glyphosate-resistant horseweed and common lambsquarters and giant ragweed populations with elevated glyphosate tolerance in the same field. A number of the weed populations expressed significant stunting from exposure to glyphosate, but were able to resume growth. Thus, researchers should evaluate plant regrowth in addition to biomass suppression when making assessments of glyphosate resistance in weed populations through greenhouse and field screening.

Inheritance of Glyphosate Resistance in Hairy Fleabane (Conyza bonariensis) from California

Weed Science ◽  
2014 ◽  
Vol 62 (2) ◽  
pp. 258-266 ◽  
Author(s):  
Miki Okada ◽  
Marie Jasieniuk
Keyword(s):  
Resistance Mechanism ◽  
Glyphosate Resistance ◽  
Population Based ◽  
Single Individual ◽  
Resistance Level ◽  
Backcross Population ◽  
Resistant Parent ◽  
Susceptible Population ◽  
Locus Model ◽  
Hairy Fleabane

Inheritance of glyphosate resistance was investigated in hairy fleabane populations from California as part of providing the information needed to predict and manage resistance and to gain insight into resistance mechanism (or mechanisms) present in the populations. Three glyphosate-resistant individuals grown from seed collected from distinct sites near Fresno, CA, were crossed to individuals from the same susceptible population to create reciprocal F1populations. A single individual from each of the F1populations was used to create a backcross population with a susceptible maternal parent, and an F2population. Based on dose response analyses, reciprocal F1populations were not statistically different from each other, more similar to the resistant parent, and statistically different from the susceptible parent, consistent with nuclear control of the trait and dominance to incomplete dominance of resistance over susceptibility in all three crosses. Glyphosate resistance in two of the three crosses segregated in the backcross and the F2populations as a single-locus trait. In the remaining cross, the resistant parent had approximately half the resistance level as the other two resistant parents, and the segregation of glyphosate resistance in backcross and F2populations conformed to a two-locus model with resistance alleles acting additively and at least two copies of the allele required for expression of resistance. This two-locus model of the segregation of glyphosate resistance has not been reported previously. Variation in the pattern of inheritance and the level of resistance indicate that multiple resistance mechanisms may be present in hairy fleabane populations in California.

Strategies for Control of Horseweed (Conyza canadensis) and Other Winter Annual Weeds in No-Till Corn

2009 ◽  
Vol 23 (3) ◽  
pp. 379-383 ◽  
Author(s):  
Gregory R. Armel ◽  
Robert J. Richardson ◽  
Henry P. Wilson ◽  
Thomas E. Hines
Keyword(s):  
Field Studies ◽  
Conyza Canadensis ◽  
Weed Species ◽  
Annual Bluegrass ◽  
No Till ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

Field studies were conducted to determine if mesotrione alone or in combinations with other corn herbicides would control horseweed and other winter annual weeds associated with no-till corn. Mesotrione alone controlled horseweed 52 to 80% by 3 wk after treatment (WAT); however, by 7 WAT control diminished to between 37 to 68%, depending on mesotrione rate. Mesotrione at 0.16 kg ai/ha plus atrazine at 0.28 kg ai/ha controlled 99% of horseweed and annual bluegrass and 88% of yellow woodsorrel. Combinations of mesotrione at 0.16 kg/ha plus acetochlor at 1.79 kg ai/ha plus 1.12 kg ai/ha glyphosate (trimethylsulfonium salt of glyphosate) or 0.7 kg ai/ha paraquat provided 93% or greater control of all three weed species. Glyphosate alone also controlled all weed species 97 to 99%, while paraquat alone provided 99% control of annual bluegrass, 72% control of horseweed, and 36% control of yellow woodsorrel. Mixtures of paraquat plus acetochlor improved control of horseweed (93%) and yellow woodsorrel (73%) over control with either herbicide applied alone.

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