scholarly journals Chemical control and herbicide resistance of hairy fleabane [Conyza bonariensis (L.) Cronquist] in Jordan

2022 ◽  
Author(s):  
Jamal R. Qasem

Two field experiments were conducted to evaluate the effectiveness of 12 herbicides in controlling hairy fleabane [ Conyza bonariensis (L.) Cronquist] in a date palm orchard located in the central Jordan valley during the spring of 2017. Results showed that C. bonariensis resists paraquat (2.5, 5 and 7.5kgha -1 ), oxadiazon (5kgha -1 ) and oxyflourfen (3.3kgha -1 ) herbicides applied at normal or higher than the recommended rates. None of the three herbicides was significantly effective against the weed and treated plants continued growing normally similar to those of untreated control. Higher rates (10-fold of the recommended rates) of the same herbicides failed to control the weed. The effect of other tested herbicides on the weed was varied with bromoxynil plus MCPA (buctril ® M), 2,4-D- iso-octyl ester, glyphosate, glyphosate trimesium and triclopyr were most effective and completely controlled the weed at recommended rates of application. Testing paraquat, oxadiazon and oxyflourfen using the normal recommended and 10-fold higher rates on two populations of C. bonariensis grown from seeds of the date palm and al-Twal (another site in the Jordan Valley) weed populations and grown in pots under glasshouse conditions showed that Date palm population was resistant to the three herbicides at both application rates while al-Twal site population was highly susceptible and completely controlled at normal and high rates of the three herbicides. It is concluded that certain populations of C . bonariensis developed resistance to paraquat, oxadiazon and oxyflourfen but control of this weed was possible using other herbicides of different mechanism of action. Herbicide rotation or other nonchemical weed control methods have been suggested to prevent or reduce the buildup and spread of resistant populations of this weed species. These results represent the first report on herbicide resistance of C. bonariensis in Jordan.

2019 ◽  
Vol 37 ◽  
Author(s):  
C. PIASECKI ◽  
A.S. MAZON ◽  
A. MONGE ◽  
J.A. CAVALCANTE ◽  
D. AGOSTINETTO ◽  
...  

ABSTRACT: Glyphosate-resistant hairy fleabane [Conyza bonariensis (L.) Cronq.] is one of the most important weeds in the world. Among the factors that make this weed species widely distributed in the most diverse environments is the high seed production capacity and dispersal. Hairy fleabane plants not controlled by herbicide application regrowth and overcome crop canopy, use environmental resources, interfere with crops, and complete their life cycle by producing thousands of seeds and replenishing the seed bank. Management strategies that reduce production and viability of hairy fleabane seeds can be adopted within the integrated management to reduce the seed bank and prevent further infestations. In this way, experiments were carried out in a greenhouse and laboratory of seed analysis to evaluate the effect of glyphosate (1,480 g a.e. ha-1) on the production and viability of glyphosate-resistant hairy fleabane seeds when applied at the vegetative and reproductive stages. Seed production was reduced by 68.4 and 100% when glyphosate was applied on hairy fleabane plants at the vegetative and early reproductive stages, respectively, regarding to the control. The viability of hairy fleabane seeds was not influenced by treatments at the evaluated stages. However, glyphosate treatment reduced the hairy fleabane seed production when applied at the vegetative stage . Hairy fleabane seed production is not feasible when glyphosate is applied at the early reproductive stage.


2006 ◽  
Vol 20 (1) ◽  
pp. 164-171 ◽  
Author(s):  
Thomas C. Mueller ◽  
Christopher L. Main ◽  
M. Angela Thompson ◽  
Lawrence E. Steckel

Greenhouse and field experiments were conducted near Knoxville, TN, during 2002 and 2003 to investigate the effects of calcium and magnesium ions on the performance of three glyphosate formulations with and without diammonium sulfate (AMS). Weed species investigated in the greenhouse were broadleaf signalgrass, pitted morningglory, Palmer amaranth, and yellow nutsedge. Three glyphosate formulations (isopropylamine salt, diammonium salt, and potassium salt) and two glyphosate application rates (0.42 and 0.84 kg ae/ha) were applied to weeds in water fortified with either calcium or magnesium at concentrations of 0, 250, 500, 750, and 1,000 ppm. In all comparisons, there were no differences in the three glyphosate formulations. Glyphosate activity was reduced only when cation concentration was >250 ppm, and this antagonism was not observed when 2% w/ w AMS was added to the spray solution. A chemical analysis of the calcium and magnesium concentrations in water collected from farmers indicated that water samples from eight different producers contained relatively low amounts of cations, with calcium at <40 ppm and magnesium at <8 ppm. In the field results using these and other waters as the herbicide carrier, broadleaf signalgrass control was greater with the 0.84 kg ae/ha than 0.42 kg ae/ha glyphosate rate regardless of water source or addition of AMS. Pitted morningglory responded similarly to glyphosate with water from all farms and with AMS added, and the addition of AMS gave similar results for both glyphosate rates. In 2003, common cocklebur was evaluated and control was >93% regardless of glyphosate rate, water source, or AMS addition. Based on these results, the addition of AMS-based adjuvants to many glyphosate applications may not be warranted.


2006 ◽  
Vol 20 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Jamal R. Qasem ◽  
Chester L. Foy

Field experiments were conducted to study the effects of oxadiazon and oxyfluorfen on weeds and Syrian marjoram (Origanum syriacumL.) in the central Jordan Valley during the period from 1998 to 2001. Results showed that weed competition with marjoram for the whole growing period resulted in almost complete crop failure. Oxyfluorfen and oxadiazon applied preplanting or postplanting to marjoram controlled weeds effectively, resulted in significant increase in marjoram shoot fresh and dry weight yields and in more branches per plant compared with the weed-infested control. High marjoram yield was obtained with oxyfluorfen applied at 0.72 kg ai/ha in preplanting treatment and with oxadiazon at 1.25 and 0.75 kg ai/ha in pre- and postplanting treatments, respectively. In preplanting treatment, 0.36 kg ai/ha of oxyfluorfen was highly selective, but 1.44 kg ai/ha reduced marjoram yield. Conflicting results were obtained with oxadiazon under the same treatments. In postplanting, oxyfluorfen at 0.24 and 0.96 kg ai/ha significantly increased marjoram yield over the weed-infested control. However, the highest shoot dry weight of marjoram was obtained at 0.96 kg ai/ha of this herbicide. In contrast, the low rate (0.38 kg ai/ha) of oxadiazon was highly selective and increased marjoram yield, but the herbicide failed to increase yield beyond the weed-infested control when the higher rate (1.5 kg ai/ha) was used. Results showed that both oxyfluorfen and oxadiazon herbicides were highly selective and effective for weed control in Syrian marjoram, providing normal rates of both are used, although high rates of the two herbicides were also selective and increased marjoram yield over the weed-infested control.


2015 ◽  
Vol 29 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Marcelo L. Moretti ◽  
Anil Shrestha ◽  
Kurt J. Hembree ◽  
Bradley D. Hanson

Hairy fleabane is an important weed in orchards and vineyards of California. Populations of glyphosate-resistant (GR) and glyphosate-paraquat-resistant (GPR) hairy fleabane have been documented in California but very little information is available on the efficacy of other POST herbicides on these populations. Greenhouse and field experiments were conducted to evaluate the efficacy of several POST herbicides registered in almond orchards on GPR, GR, and glyphosate/paraquat-susceptible (GPS) hairy fleabane plants. Plants were treated at the 8- to 12-leaf stage in greenhouse experiments, and at the bolting to flowering stage in field experiments. A sequential application of glyphosate (1,100 g ae ha−1) followed by paraquat (500 g ai ha−1) 14 d later did not control the GPR plants in any of the studies, but was effective in controlling the GR and GPS plants. Glufosinate at 1,050 g ai ha−1or saflufenacil at 48.8 g ai ha−1resulted in 90% or greater control of all populations in all studies, whereas glyphosate (1,100 g ae ha−1) + 2,4-D (1,090 g ae ha−1) resulted in inconsistent control (58 to 100%). The GPR population was not resistant to other common POST herbicide modes of action used in California tree nut orchards, and glufosinate and saflufenacil can provide growers effective management options for hairy fleabane in these crops.


Weed Science ◽  
1992 ◽  
Vol 40 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Tracy E. Klingaman ◽  
Charles A. King ◽  
Lawrence R. Oliver

Field experiments were conducted in 1986, 1987, and 1988 to evaluate imazethapyr rate and time of application on postemergence control of 24 weed species. Contour graphs were developed that predicted imazethapyr rates required for various levels of weed control based upon weed leaf number at application. Rates below the labeled rate (70 g ha−1) provided 90% or greater control of common cocklebur, smallflower morningglory, and smooth pigweed if applied to 3 true-leaf or smaller weeds and of barnyardgrass, seedling johnsongrass, and Palmer amaranth if applied while weeds were in the cotyledon or 1 true-leaf stage. A rate of 70 g ha−1provided 90% control of large crabgrass in the 1 true-leaf stage. Entireleaf morningglory, red rice, pitted morningglory, and velvetleaf are not susceptible enough to imazethapyr for 90% or greater control to be obtained with rates lower than 70 g ha−1at the 1 true-leaf growth stage. These data demonstrate how control data can be used for developing effective reduced-rate herbicide recommendations based on weed leaf number.


2004 ◽  
Vol 18 (3) ◽  
pp. 801-809 ◽  
Author(s):  
Peter H. Sikkema ◽  
Allan S. Hamill ◽  
Mirwais M. Qaderi ◽  
Colleen Doucet

Field experiments were conducted in 1998, 1999, and 2000 at two locations (Harrow and Ridgetown) in southwestern Ontario to determine the biologically effective rates (I90) of a commercial formulation of flufenacet plus metribuzin for weed control and processing tomato tolerance. At the proposed label use rate, flufenacet plus metribuzin provided excellent (≥90%) early-season (22 to 29 d after planting) control of velvetleaf, good (80 to 89%) control of barnyardgrass and redroot pigweed, and fair (60 to 79%) control of common lambsquarters. Flufenacet plus metribuzin provided fair late-season (59 to 97 d after planting) control of redroot pigweed and common lambsquarters and poor (≤59%) control of barnyardgrass and velvetleaf. At Harrow and Ridgetown, I90values for early-season weed control ranged from 70 to 1,300 g ai/ha and 50 to 1,900 g ai/ha, respectively. Flufenacet plus metribuzin provided poor weed control at Ridgetown. This result was not attributable to higher weed density or particular weed species but may have been caused by lack of rainfall and too low application rates for the medium-textured soil type. It is estimated that flufenacet plus metribuzin at 1,400 g/ha can control green foxtail season-long, whereas barnyardgrass and common lambsquarters would require 1,900 g/ha. Season-long control of velvetleaf and redroot pigweed would require application rates of 3,200 and 7,100 g/ha, respectively. Only slight early-season crop injury was observed, which was not reflected in yields. Optimum yields of tomatoes were obtained at Harrow at rates lower or slightly higher than the registered rates for corn and soybean. Tomato yields were higher at Harrow than at Ridgetown, which may have been due to differences in soil texture. Tomatoes grown in a medium-textured (Ridgetown) soil appeared to be less competitive against weeds than those grown in a coarse-textured soil (Harrow).


2006 ◽  
Vol 20 (3) ◽  
pp. 793-814 ◽  
Author(s):  
Hugh J. Beckie

In input-intensive cropping systems around the world, farmers rarely proactively manage weeds to prevent or delay the selection for herbicide resistance. Farmers usually increase the adoption of integrated weed management practices only after herbicide resistance has evolved, although herbicides continue to be the dominant method of weed control. Intergroup herbicide resistance in various weed species has been the main impetus for changes in management practices and adoption of cropping systems that reduce selection for resistance. The effectiveness and adoption of herbicide and nonherbicide tactics and practices for the proactive and reactive management of herbicide-resistant (HR) weeds are reviewed. Herbicide tactics include sequences and rotations, mixtures, application rates, site-specific application, and use of HR crops. Nonherbicide weed-management practices or nonselective herbicides applied preplant or in crop, integrated with less-frequent selective herbicide use in diversified cropping systems, have mitigated the evolution, spread, and economic impact of HR weeds.


2012 ◽  
Vol 26 (2) ◽  
pp. 230-235 ◽  
Author(s):  
Andrew G. Hulting ◽  
Joseph T. Dauer ◽  
Barbara Hinds-Cook ◽  
Daniel Curtis ◽  
Rebecca M. Koepke-Hill ◽  
...  

Management of Italian ryegrass in cereal-based cropping systems continues to be a major production constraint in areas of the United States, including the soft white winter wheat producing regions of the Pacific Northwest. Pyroxasulfone is a soil-applied herbicide with the potential to control broadleaf and grass weed species, including grass weed biotypes resistant to group 1, 2, and 7 herbicides, in several crops for which registration has been completed or is pending, including wheat, corn, sunflower, dry bean, and soybean. Field experiments were conducted from 2006 through 2009 near Corvallis, OR, to evaluate the potential for Italian ryegrass control in winter wheat with applications of pyroxasulfone. Application rates of PRE treatments ranged from 0.05 to 0.15 kg ai ha−1. All treatments were compared to standard Italian ryegrass soil-applied herbicides used in winter wheat, including diuron, flufenacet, and flufenacet + metribuzin. Visual evaluations of Italian ryegrass and ivyleaf speedwell control and winter wheat injury were made at regular intervals following applications. Winter wheat yields were quantified at grain maturity. Ivyleaf speedwell control was variable, and Italian ryegrass control following pyroxasulfone applications ranged from 65 to 100% and was equal to control achieved with flufenacet and flufenacet + metribuzin treatments and greater than that achieved with diuron applications. Winter wheat injury from pyroxasulfone ranged from 0 to 8% and was most associated with the 0.15–kg ha−1application rate. However, this early-season injury did not negatively impact winter wheat yield. Pyroxasulfone applied at the application rates and timings in these studies resulted in high levels of activity on Italian ryegrass and excellent winter wheat safety. Based on the results, pyroxasulfone has the potential to be used as a soil-applied herbicide in winter wheat for Italian ryegrass management and its utility for management of other important grass and broadleaf weeds of cereal-based cropping systems should be evaluated.


2020 ◽  
Vol 71 (9) ◽  
pp. 864
Author(s):  
Charlotte Aves ◽  
John Broster ◽  
Leslie Weston ◽  
Gurjeet S. Gill ◽  
Christopher Preston

Conyza bonariensis (L.) Cronq. (syn. of Erigeron bonariensis L.) is a difficult-to-control summer weed species in the cropping belt of south-eastern Australia. Herbicide resistance may be affecting the ability to control C. bonariensis in the agricultural region of north-eastern Victoria; therefore, a survey was conducted to evaluate resistance to herbicides from several mode-of-action groups. Of the populations collected, 40% were resistant to glyphosate at 1080 g ha–1. Chlorsulfuron failed to control any of the populations collected. Further research identified multiple herbicide resistance to glyphosate, chlorsulfuron, metsulfuron-methyl and sulfometuron-methyl in five of nine populations fully characterised. Resistance was not found to 2,4-D, clopyralid or paraquat. There was no correlation between prevailing land use and the frequency of glyphosate-resistant populations, suggesting that resistance had been selected in multiple production systems. The high frequency of resistance could explain the difficulty experienced in controlling C. bonariensis across north-eastern Victoria and demonstrates the importance of integrated weed management to manage this weed.


2020 ◽  
pp. 1-7
Author(s):  
Travis R. Russell ◽  
Tim T. Lulis ◽  
Brian A. Aynardi ◽  
Kaiyuan T. Tang ◽  
John E. Kaminski

Abstract Buckhorn plantain populations purportedly resistant to 2,4-D were identified in Pennsylvania following long-term, continual applications of the active ingredient to turfgrass. The research objectives of this study were to 1) confirm 2,4-D resistance with dose-response experiments, 2) confirm field resistance of buckhorn plantain to 2,4-D in Pennsylvania, and 3) evaluate alternative herbicides for 2,4-D-resistant buckhorn plantain. Greenhouse dose-response experiments evaluated the sensitivity of buckhorn plantain biotypes that were resistant or susceptible to 2,4-D, and to halauxifen-methyl, two synthetic auxin herbicides from different chemical families. The resistant biotype was ≥11.3 times less sensitive to 2,4-D than the susceptible biotype and required a 2,4-D dosage ≥4.2 times greater than the standard application rate to reach 50% necrosis. No cross-resistance was observed to halauxifen-methyl because both resistant and susceptible populations demonstrated similar herbicide sensitivity. Field experiments confirmed previous reports of ineffectiveness (≤30% reduction) with 2,4-D and other phenoxycarboxylic herbicides in potentially resistant buckhorn plantain biotypes. Treatments containing halauxifen-methyl resulted in a ≥70% reduction in resistant biotypes. This is the first known report of synthetic auxin herbicide resistance in any weed species in Pennsylvania and highlights emerging herbicide resistance challenges in turfgrass systems.


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