Download or read book Investigation Into the Control of Glyphosate resistant Canada Fleabane Conyza Canadensis L Cronq and Glyphosate resistant Giant Ragweed Ambrosia Trifida L Using Isoxaflutole and Metribuzin written by Scott Ditschun and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Farmers in southern Ontario face a significant threat from glyphosate-resistant weeds such as Canada fleabane and giant ragweed. Left uncontrolled, glyphosate-resistant weed interference in soybean can result in substantial yield loss. The three objectives of this study were: 1) to determine the biologically effective rate of isoxaflutole, metribuzin, and glyphosate on glyphosate-resistant Canada fleabane and giant ragweed biotypes, 2) to assess the response of isoxaflutole and glyphosate applied as a tank-mix on glyphosate-resistant and glyphosate-susceptible biotypes of both species, and 3) to ascertain the response of isoxaflutole, metribuzin and glyphosate tank-mix on the glyphosate-resistant biotypes of both species. In growth room experiments, antagonism is observed at low rates of glyphosate plus isoxaflutole in glyphosate-susceptible giant ragweed and at field rates of the same tank-mix in glyphosate-resistant Canada fleabane. The addition of metribuzin to the tank-mix resulted in an additive or synergistic response across all rates in the glyphosate-resistant biotypes of both species tested. Field experiments confirmed the additive and synergistic response of the three-way tank-mix in both species tested. An estimated 631 (126+504) and 420 (84+336) g a.i. ha-1 of isoxaflutole plus metribuzin in a 1:4 ratio are required for control of glyphosate-resistant giant ragweed and Canada fleabane respectively.

Download or read book Evaluation of Halauxifen methyl for the Control of Glyphosate Resistant Canada Fleabane Conyza Canadensis L Cronq and Giant Ragweed Ambrosia Trifida L in Winter Wheat and Soybean written by Jessica E. Quinn and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The new herbicide halauxifen-methyl was evaluated for the control of glyphosate-resistant (GR) Canada fleabane and giant ragweed in winter wheat and soybean, and the tolerance of corn and soybean to halauxifen-methyl. Halauxifen-methyl applied alone or in a tankmix controlled GR Canada fleabane in winter wheat, while a tankmix partner was required to provide control in soybean. Halauxifen-methyl applied alone did not control GR giant ragweed in winter wheat or soybean, however, when applied in a tankmix, control was achieved. Halauxifen-methyl applied preplant and pre-emergence at 5 g ai ha-1 and 10 g ai ha-1 was safe in corn however yield was reduced when applied early postemergence at the 10 g ai ha-1 rate. Soybean was extremely sensitive to halauxifen-methyl applied early postemergence at both rates, however minimal injury was observed when either rate was applied preplant and pre-emergence. Halauxifen-methyl could provide an effective solution for the control of GR weeds in corn, soybean and winter wheat.

Download or read book Characterization and Management of Glyphosate resistant Giant Ragweed Ambrosia Trifida L and Horseweed Conyza Canadensis L Cronq written by Jeff Michael Stachler and published by . This book was released on 2008 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research confirms the presence of low-level glyphosate resistance in giant ragweed, and multiple-resistance in horseweed, to glyphosate and ALS-inhibiting herbicides. This is the first confirmation of these resistant cases in the world. Resistant populations can be effectively managed where the herbicide program includes 2,4-D and residual herbicides, applied prior to soybean planting at the appropriate weed growth stage. For giant ragweed, the preplant herbicide treatment must be followed by multiple postemergence applications of glyphosate at maximum rates, or effective alternatives to glyphosate.

Download or read book Glyphosate resistant Canada Fleabane Conyza Canadensis L Cronq in Ontario written by Holly P. Byker and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Canada fleabane is the second glyphosate-resistant (GR) weed species to be confirmed in Ontario. In 2010, GR populations were identified at eight sites in Essex County. In 2011 and 2012, 147 additional sites across eight counties were confirmed to be resistant. Twelve and seven sites were identified with multiple resistance (glyphosate and cloransulam) in 2011 and 2012, respectively, across five counties. In soybeans, preplant tankmixes of glyphosate (900 g a.e.ha-1) plus saflufenacil (25 g a.i. ha-1), saflufenacil/dimethenamid-p (245 g a.i. ha-1), metribuzin (1120 g a.i. ha-1), or flumetsulam (70 g a.i. ha-1) provided greater than 87% up to 8 weeks after application (WAA). Glyphosate rates 21 to 48X the label rate (900 g a.e. ha-1) were required for 95% control. Postemergence tankmixes did not provide acceptable control. In dicamba-tolerant soybean, dicamba applied preplant at 600 g a.e. ha-1 provided the most consistent control of GR Canada fleabane.

Download or read book Control of Glyphosate Resistant Canada Fleabane Conyza Canadensis L Cronquist with 2 4 D Choline Glyphosate DMA in Corn Zea Mays L written by Laura Ford and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improving the Consistency of Glyphosate resistant Canada Fleabane Conyza Canadensis Control with Saflufenacil written by Christopher Murray Budd and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2010, glyphosate-resistant (GR) biotypes of Canada fleabane were first confirmed in Essex County, Ontario. From surveys conducted in 2010 to 2015, inclusive, GR Canada fleabane has now been confirmed in 30 counties and multiple-resistant biotypes (glyphosate and cloransulam-methyl) in 22 counties. Saflufenacil was recommended for GR Canada fleabane control in soybean, however variable control had been reported. The biologically effective rate (BER) of saflufenacil is 25 g a.i. ha-1 for 90% control eight weeks after application (WAA). At 8 WAA, the BER of metribuzin when tankmixed with glyphosate (900 g a.i. ha-1) plus saflufenacil (25 g a.i. ha-1) was 61, 261, and 572 g a.i. ha-1 for 90, 95 and 98% control, respectively. Tankmix partners with glyphosate (900 g a.i. ha-1) plus saflufenacil (25 g a.i. ha-1) were investigated, and the best three-way tankmixes were with either 2,4-D or metribuzin for full season control of multiple-resistant Canada fleabane. The optimal time of day (TOD) for controlling GR Canada fleabane with glyphosate (900 g a.i. ha-1) plus saflufenacil (25 g a.i. ha-1) was 09:00-21:00 h. GR Canada fleabane height and density were found to have a minimal effect on control with glyphosate (900 g a.i. ha-1) plus saflufenacil (25 g a.i. ha-1).

Download or read book Control of Glyphosate Resistant Canada Fleabane Conyza Canadensis and Waterhemp Amaranthus Tuberculatus Var Rudis in Glyphosate Dicamba Resistant Soybean Glycine Max written by Brittany Hedges and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Field studies were conducted in Ontario, Canada on the control of glyphosate-resistant (GR) Canada fleabane and waterhemp in 2016 and 2017. Glyphosate/dicamba was applied to Canada fleabane at 3 postemergent (POST) application timings (5, 15 and 25 cm) and 4 herbicide rates (0, 900, 1350 and 1800 g ae ha-1). An increase in plant height at the application timing, led to a decrease in control of Canada fleabane; an increase in herbicide rate led to an increase in efficacy. There was an interaction between application timing and rate for density and biomass only. This same study was conducted with GR waterhemp, the same trend followed except there was no interaction between application timing and herbicide rate. Control of GR Canada fleabane with several preplant herbicide tankmixes was evaluated; there was no increase in control with the addition of a second-effective site-of-action. Similarly, GR waterhemp control did not increase with the addition of a second-effective mode-of-action. Acceptable control was not obtained with glyphosate/dicamba applied pre-emergent (PRE), therefore, another mode-of-action is needed for effective control of GR waterhemp. A two-pass program of an effective PRE herbicide followed by glyphosate/dicamba provided season-long control of GR waterhemp and was more efficacious than a PRE or POST program alone.

Download or read book Improving the Level and Consistency of Glyphosate Resistant Canada Fleabane Erigeron Canadensis L Control in Soybean Glycine Max L Merr with Preplant Herbicides written by Meghan Dilliott and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Six studies consisting of twenty four field experiments were conducted in 2020 and 2021 in Ontario, Canada to investigate how to improve the level and consistency of glyphosate-resistant (GR) Canada fleabane control with herbicides applied preplant (PP) to soybean. Study One concluded the adding saflufenacil or metribuzin to glyphosate plus halauxifen-methyl or pyraflufen-ethyl/2,4-D resulted in a synergistic increase in GR Canada fleabane control and improved the consistency of control. Study Two and Three determined adding dicamba or saflufenacil to glyphosate plus bromoxynil and adding saflufenacil to glyphosate plus dicamba improved the level and consistency of GR Canada fleabane control. Study Four determined adding metribuzin to glyphosate plus glufosinate provided the greatest level of GR Canada fleabane control and improved the consistency of control. Study Five and Six determined there was no benefit of adding low rates of protoporphyrinogen oxidase (PPO)-inhibiting herbicides to glufosinate to improve GR Canada fleabane control.

Download or read book Glyphosate Resistant Giant Ragweed Ambrosia Trifida L in Ontario written by Joseph Vink and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Giant ragweed is an extremely competitive weed and poor control in soybean could lead to significant yield losses for Ontario producers. In 2008, a giant ragweed biotype near Windsor, ON was not controlled with glyphosate and further testing confirmed it as the first glyphosate-resistant (GR) weed in Canada. Giant ragweed seed was collected from 102 locations in Essex (70), Kent (21), Lambton (10) and Waterloo (1) counties to document the occurrence and distribution of GR giant ragweed in Ontario. Giant ragweed seedlings were sprayed with glyphosate at 1800 g a.e. ha-1, and evaluated 1, 7, 14 and 28 days after application (DAA). Results from the survey concluded that there are 47 additional locations in southwestern Ontario with GR giant ragweed. The majority of the sites were found in Essex county, but there was one location in both Chatham-Kent and Lambton counties. Field trials were established at six sites with GR giant ragweed during the 2010 and 2011 growing seasons. The objectives were to determine the level of giant ragweed control with increasing doses of glyphosate, and glyphosate tank mixes applied either preplant or postemergence. Control of giant ragweed increased with higher doses of glyphosate, but only at doses that are not economical for producers. The most effective glyphosate tank mixes were 2, 4-D ester, saflufenacil, linuron, and cloransulam-methyl providing up to 98, 94, 99 and 97% control 4 weeks after application (WAA), respectively. Glyphosate plus dicamba in dicamba-tolerant soybean provided up to 100% giant ragweed control, 4 WAA at the three confined field trial locations.

Download or read book An Integrated Weed Management Strategy for the Control of Canada Fleabane Conyza Canadensis L Cronq written by Theodore Ross Vanhie and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Reports of herbicide-resistant weeds continue to rise at an increasing rate, despite current efforts to mitigate this issue. The repeated use of glyphosate resulted in glyphosate-resistant Canada fleabane [Conyza canadensis (L.) Cronq.] populations in Delaware, USA, in 2001, and Ontario, Canada, in 2010. Research has reported rye (Secale cereale L.) cover crops consistently reduced the density and height of Canada fleabane. This research examined if fall-seeded rye can suppress Canada fleabane seedling density and growth, then the interaction(s) of multiple selection pressures should enhance Canada fleabane control which aids farmers in developing integrated weed management strategies. In 2018 and 2019, field studies were conducted to evaluate the interactions between fall-seeded rye cover crops, shallow fall tillage, and spring-applied herbicides. Interactions between selection pressures were observed to have an additive effect on improving weed control; environmental variables, however, had a direct influence on these interactions.

Download or read book Biology and Management of Horseweed and Hairy Fleabane in California written by and published by UCANR Publications. This book was released on 2008 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Horseweed and hairy fleabane are showing increased resistance to chemical controls, including glyphosate. By learning about their biology and other control alternatives, you can do a better job of keeping on top of this pest problem.

Download or read book Investigation of Glyphosate resistant Horseweed Conyza Canadensis L Cronq in Tennessee written by Christopher L. Main and published by . This book was released on 2005 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of Herbicide Programs for the Management of Glyphosate resistant Giant Ragweed in Soybean written by Eric Brandon Riley and published by . This book was released on 2013 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, glyphosate-resistant (GR) giant ragweed (Ambrosia trifida L.) has become an increasingly problematic weed of soybean production systems in Missouri and throughout the Midwest. As of 2013, giant ragweed has been confirmed with resistance to glyphosate in 11 states and one Canadian province. The objectives of this research were to determine the effect of herbicide application timing and glyphosate tank-mix combinations on the survival of GR giant ragweed and the influence of pre-plant (PREPLT) followed by (fb) 2-pass post-emergence (POST) herbicide programs in GR and glufosinate-resistant soybean on GR giant ragweed density, soybean yield, and net economic return. Results from this research indicate that POST applications to smaller plants can reduce the survival of giant ragweed compared to applications to larger plants. For a POST only management strategy, fomesafen plus glyphosate applied to 10-cm plants fb glyphosate late post-emergence (LPOST) resulted in 37% survival and was the lowest survival observed. Overall, giant ragweed was nearly eliminated with PREPLT fb 2-pass POST programs. For example, no more than 6 plants 5-m-2 were observed if PREPLT applications contained an effective tank-mix combination in either soybean system. However, 244 plants 5-m-2 were observed following a program that consisted of glyphosate PREPLT fb glyphosate plus fomesafen early post-emergence (EPOST) fb glyphosate LPOST. Few differences in yield or net return were observed in the PREPLT experiments. However, programs that contained an effective PREPLT application generally resulted in higher yield and net economic return. Results from this research indicate that PREPLT applications can provide more effective control of giant ragweed compared to POST-only programs.

Download or read book Programmed Cell Death and Altered Translocation Cause Glyphosate Resistance in Giant Ragweed Ambrosia Trifida L written by Mackenzie Anne Lespérance and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanisms of resistance to the herbicide glyphosate in Canadian biotypes of giant ragweed are currently unknown. In Ontario, a glyphosate resistant (GR) biotype shows a distinct phenotypic response in the mature leaves characterized by a light-dependent, hydrogen peroxide induced, rapid-necrosing reaction to glyphosate, leaving meristems intact. To gain insight into the subcellular events leading to damage in the mature leaves, transmission electron microscopy was used to compare cellular morphology between GR and glyphosate susceptible (GS) biotypes. Morphological evidence of different programmed cell deaths (PCD) were observed between GR and GS biotypes and a rapid increase in starch accumulation was observed in the GR biotype. This evidence was accompanied by a time lapse quantification of [14C]-glyphosate through biological oxidation and liquid scintillation when application was specific to the apical meristem of GR and GS plants. At 24 hours after application, [14C]-glyphosate was shown to increase in the mature leaves and decrease in the apical meristem of GR plants in comparison to GS plants (P

Download or read book Confirmation and Management of Multiple Resistance of Horseweed Conyza Canadensis L Cronq to Glyphosate and Paraquat written by Thomas William Eubank and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Glyphosate-resistant (GR) horseweed has become a major problem in many row crop production systems in the United States. Horseweed is a winter annual weed common in no-till production systems. Fall-applied herbicides were compared with spring-applied treatments for the control of horseweed. In cotton, fall-applied trifloxysulfuron provided similar or greater control of horseweed when compared to spring-applied treatments of glyphosate + dicamba. Cotton yields with fall-applied trifloxysulfuron, clomazone, and flumioxazin were comparable to or better than spring-applied glyphosate + dicamba both years. Fall-applied cloransulam-methyl, flumetsulam, sulfentrazone, and the combination of chlorimuron-ethyl + metribuzin resulted in horseweed control and soybean yields comparable to spring-applied glyphosate + 2,4-D both years. Multiple-resistance to glyphosate and paraquat exists in a horseweed population from Mississippi. Herbicide rates of 0.066 kg ae/ha glyphosate and 0.078 kg ai/ha paraquat were required to reduce susceptible horseweed biomass 50%; whereas, rates of 0.78 kg/ha glyphosate and 0.67 kg/ha paraquat were required to reduce biomass of resistant horseweed to a similar intent. This is the first broadleaf weed species reported as exhibiting multiple-resistance to glyphosate and paraquat. The addition of metribuzin to paraquat improved control of paraquatresistant horseweed. Paraquat at 0.84 kg/ha plus all rates of metribuzin controlled 15-cm tall horseweed at least 90% both years compared to 73% with 0.84 kg/ha paraquat alone. The addition of 1 and 2% methylated seed oil (MSO) to saflufenacil controlled horseweed 91 and 93%, respectively compared to 78% control with saflufenacil alone. The addition of saflufenacil to glyphosate improved control of GR horseweed from 50% to 100% at 21 d after treatment; control of horseweed with the combination of saflufenacil + glyphosate was additive. Saflufenacil did not affect absorption of glyphosate in glyphosate-susceptible horseweed; however, absorption increased in GR horseweed from 36 to 44% at 48 h after treatment with the addition of saflufenacil when compared to glyphosate alone treatments. Overall, the addition of saflufenacil reduced glyphosate translocation in horseweed at least 6%; however, due to the exceptional efficacy of saflufenacil on horseweed these reductions did not reduce control of GR horseweed.

Download or read book Resistance Mechanism Control and Characterization of Glyphosate resistant Giant Ragweed Ambrosia Trifida L in Mississippi written by Tripp Walker and published by . This book was released on 2019 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glyphosate-resistant (GR) giant ragweed (Ambrosia trifida L.) has been confirmed in several states across the mid-western and mid-southern U.S. Greenhouse and lab studies were conducted to investigate possible mechanism of glyphosate resistance in a suspect population from Monroe County, Mississippi. Translocation of 14C-glyphosate in the susceptible biotype was 77%, compared to 12% in the resistant biotype at 120 hours after treatment, suggesting that the glyphosate resistance mechanism for this giant ragweed biotype is reduced translocation. Dose response studies were conducted to confirm and characterize glyphosate resistance in suspect biotypes from Mississippi (MS-R) and Tennessee (TN-R). The ED50 for MS-R and TN-R were 3.9- and 6.3-fold higher than a susceptible biotype. Results from a fallow field study conducted in 2016 in Monroe County revealed PRE and POST treatments containing dicamba and mesotrione alone and in various combinations provided effective control of GR giant ragweed. Studies were conducted to measure fitness, phenotypic, and genetic variation among GR biotypes from MS-R, TN-R, and Ohio (OH-R). Non-destructive measurements of plants over an eight-week period revealed rapid early growth of two GR accessions from MS in the absence of glyphosate. However, no differences in vegetative biomass were recorded after eight weeks with the exception of OH-R biotype which exhibited lower biomass due to photoperiod sensitivity. Vegetative biomass and fecundity were similar. Multivariate and PCA analysis of traits grouped biotypes based on state of origin. Groupings by state of origin can be significant as managers could design similar methods of control to address giant ragweed in these areas. Simple sequence repeat (SSR) markers were used to record genetic diversity among and within biotypes. Genetic diversity values were high at 0.514, 0.502, and 0.525 within biotypes from MS, TN, and OH, respectively. However, genetic diversity did not differ due to glyphosate response or level of glyphosate resistance. High levels of genetic variation can be an indicator of the ability of giant ragweed biotypes to adapt to changing environments and conditions.

Download or read book Distribution and Control of Glyphosate resistant Common Ragweed Ambrosia Artemisiifolia L in Ontario Soybeans Glycine Max L Merr written by Annemarie Van Wely and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: