Download or read book Horseweed Management with Shading and Cover Crops and the Tolerance of Two Horseweed Growth Types to Glyphosate written by Justine Lynn Fisher and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Field experiments were conducted to evaluate if fall-planted cereal rye in combination with narrow row soybean improved glyphosate-resistant (GR) horseweed management. At the time of a postemergence herbicide application (POST), horseweed biomass was 71 to 90% lower when soybean was planted into cereal rye, regardless of termination time, compared with no cover across all row widths. Planting green or narrow row soybean suppressed horseweed through soybean harvest and integrating an effective POST herbicide improved control. Additional field experiments found that in the absence of an effective POST herbicide, horseweed biomass was 42 and 81% lower by planting green or applying a residual herbicide compared with no cover, respectively, at soybean harvest. Similarly, planting soybean in 19 cm rows reduced horseweed biomass compared with 38 and 76 cm rows. In the greenhouse, shade levels from 35 to 92% reduced rosette and upright horseweed biomass 31 to 99% compared with the upright-type grown under 0% shade. Greater reductions occurred under 69 and 92% shade. Differences in glyphosate sensitivity between the rosette and upright horseweed growth types were not due to absorption, translocation, or total glyphosate retention; however, glyphosate retention was 21 and 18% lower on a per weight and area basis for the upright growth type. This diluted concentration may contribute to increased glyphosate tolerance found in the upright growth type. However, other factors such as differences in EPSPS gene expression may also help explain differential sensitivity if a target-mutation is discovered. This research provides growers strategies for managing horseweed and insight into potential growth type differences.

Download or read book Horseweed Growth Types and Integrating Fall planted Cereal Cover Crops for Management written by John Allen Schramski and published by . This book was released on 2020 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent shifts in glyphosate-resistant horseweed (Erigeron canadensis L.) emergence patterns and growth types at the field level have generated new management questions. Field experiments investigated the effects of cereal rye and winter wheat, seeded at 67 or 135 kg ha-1, in combination with burndown herbicide strategies or terminated at different times for managing horseweed in no-tillage soybean. In absence of effective herbicides, fall-planted cereal cover crops reduced horseweed biomass up to 70 and 33% at cover termination and five weeks after soybean planting, respectively. Integrating effective herbicide strategies improved horseweed suppression and soybean yield. Delaying termination by Planting Green improved horseweed suppression through the time of postemergence application. Additional field experiments evaluated the effects of termination timing and herbicide combinations for cereal rye termination. Glyphosate applied at 1,267 g ae ha-1 to cereal rye at early (Feekes 6) or late (Feekes 10.5) growth stages effectively terminated cereal rye. The addition of dicamba to glyphosate applied late, or clethodim alone provided less control. All herbicide combinations tested, with the exception of those which included metribuzin, provided similar control to glyphosate alone. In controlled environment experiments, a vernalization period following imbibition of water, but prior to germination, induced horseweed bolting at emergence. Additionally, bolted type horseweed in glyphosate-resistant populations was less sensitive to glyphosate than rosette type. This research provides growers strategies for managing horseweed and insight into the recent glyphosate-resistant horseweed emergence and growth type phenomena observed in the field.

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 Biology and Management of Horseweed written by Mark Loux and published by . This book was released on 2005 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cover Crops for Horseweed Conyza Canadensis L Control Before and During a Soybean Crop written by Andi Marie Christenson and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing numbers of herbicide-resistant weed species require alternative methods of weed suppression to be examined. This study quantified the interaction between various cover crop or herbicide systems and horseweed [Conyza canadensis (L.)] growth. Fall cover crops of winter wheat [Triticum aestivum (L.)], winter rye [Secale cereal (L.)], barley [Hordeum vulgare (L.)] and annual ryegrass [Lolium multiflorum (L.)] were seeded in November 2012 and 2013. Spring cover crop of oat [Avena sativa (L.)] was seeded in April 2013 or rye was seeded in March 2014. All cover crops were no-till seeded into grain sorghum stubble [Sorghum bicolor (L.) Moench]. Four herbicide treatments were fall or spring applied, with and without residual. The spring non-residual treatment was also applied to plots of winter rye. Cover crop plots were split and terminated with a roller crimper or glyphosate application prior to soybean [Glycine max (L.) Merr.] planting to determine the effect of termination method on treatment performance. Soybean was planted in June 2013 and May 2014 and mechanically harvested in October of both years. Horseweed density, biomass accumulation, and soybean yield data were quantified. Horseweed height, whole plant seed production, and seed subsamples were recorded in the untreated fallow control, winter wheat, and winter rye plots in 2014. Horseweed suppression by winter rye approached 90%, levels similar to suppression by herbicide systems. In both years, herbicide plots had less than half the horseweed biomass than any of the cover crop systems. In 2013, soybean yields in herbicide plots were at least 1,500 kg ha−1, nearly more than double yields in cover crop plots. Soybean yields in 2014 were more consistent across treatments; barley and spring rye plots achieved yields equal to or greater than 2,000 kg ha−1. Winter rye and winter wheat reduced horseweed seed production by 60% compared to the untreated fallow control, with no effect on individual seed weight. Seed production varied across plants, with the untreated control producing the greatest number of seeds. Cover crops were successful at reducing horseweed biomass, suppressing horseweed pressure, preserving soybean biomass, and protecting soybean yields when compared to a fallow untreated control.

Download or read book Integrating Cover Crops and Herbicides for Horseweed and Palmer Amaranth Management in No till Soybean written by Chelsea Marie McCall and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Palmer amaranth and horseweed are problematic weeds in no-till soybeans in Kansas. Integrating cover crops and herbicide programs could suppress weed populations. To determine the emergence pattern and survival of horseweed, a study was conducted across six locations in eastern KS in 2014-2015 and 2015-2016. Horseweed seedlings and leaf number per seedling were recorded at two-week intervals. Cumulative GDDs required to reach 50% horseweed emergence increased from north to south. Horseweed survival ranged from 4 to 90%, and majority of horseweed emerged in the fall. Field studies were conducted to determine effects of cover crops and herbicide programs on Palmer amaranth near Manhattan, KS in 2014-2015 and 2015-2016. Five cover crop treatments included no cover, fall-sown winter wheat, spring-sown oat, pea, and mixture of oat and pea. Cover crops were terminated in May with glyphosate and 2,4-D alone or with residual herbicides of flumioxazin and pyroxasulfone. By 10 weeks after termination in 2014-2015, Palmer amaranth biomass and density, averaged across cover crops. was 95 and 69% less with residual herbicides than without, respectively, and Palmer amaranth biomass was 98% less in winter wheat and 91% less in spring oat, averaged across termination methods, compared to no cover. Time to 50% Palmer amaranth emergence was delayed with winter wheat, spring oat, and spring oat/pea mix without residual herbicide. Soybean yields were greater with residual herbicide and greater with winter wheat or spring oat cover crop in 2014-2015. A field study was conducted to determine suppression effects of cover crop and herbicide programs on horseweed and Palmer amaranth near Manhattan, KS in 2015-2016. Three fall treatments included fall-sown rye, a residual herbicide tank mix of glyphosate, dicamba, chlorimuron-ethyl, tribenuron-methyl, and AMS, and no fall application. Four spring treatments included no spring application or three herbicide tank mixes: glyphosate, dicamba, and AMS alone or with flumioxazin and pyroxasulfone as early preplant, or as split applied with 2/3 preplant and 1/3 at soybean planting. Similar levels of horseweed suppression were observed when some control measure was used in fall or spring. Fall rye completely suppressed horseweed while the fall herbicide suppressed biomass by 93% and density by 86% compared to no fall application. Palmer amaranth suppression was observed when a spring herbicide application was used. In rye, total weed biomass was reduced by 97% or more across all spring treatments. Total weed biomass was reduced with a spring herbicide was used. Soybean yields were least when no herbicide treatment was used in the spring. An integrated program of fall cover crops or herbicide applications together with spring herbicide applications maintained soybean yields.

Download or read book Evaluating Cover Crops and Herbicides for Horseweed and Palmer Amaranth Management written by Larry Joe Rains (III) and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Horseweed and Palmer amaranth are common weeds in Kansas that compete against many row crops. Horseweed can emerge in different seasons depending on the year. Palmer amaranth emerges from spring throughout the summer months and has a rapid growth rate with higher temperatures. Three separate studies were conducted near Manhattan, KS from 2016 to 2018 to determine (1) horseweed control in no-till soybean with cover crops and herbicide programs with and without residual activity (2) emergence timing in KS of eight horseweed populations collected from MO, IL, KS, and KY, and (3) Palmer amaranth control in response to three Protoporphyrinogen Oxidase (PPO) inhibitors applied every three days once Palmer amaranth plants reached 2.5 cm tall. Cereal rye reduced weeds biomass by 78% and weed density by 75% by 8 weeks after cover crop seeding in the fall. At cover crop termination two weeks prior to soybean drilling. Cereal rye reduced horseweed biomass more than herbicide treatments, but after termination weed control was similar across treatments. Soybean yields were greater with herbicide treatments in year one, but there were no differences in soybean yields among cover crop and herbicide treatments in the second year. Emergence of all eight horseweed populations occurred at the same time. Most horseweed emergence occurred in the spring in the first year, while all horseweed populations emerged in the fall in the second year. Environmental conditions were driving factors for horseweed emergence, but horseweed seed source did not influence emergence timing. All PPO-inhibitor herbicides controlled Palmer amaranth at similar levels within an application timing. PPO-inhibitor herbicides need to be applied within three days after Palmer amaranth plants reach 2.5 cm tall to achieve greater than 90% control.

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 Biology and Management of Horseweed and Hairy Fleabone in California written by Anil Shrestha and published by . This book was released on 2008 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Glyphosate resistant and Susceptible Horseweed Biotypes in the Vineyard written by Marisa Fe Alcorta and published by . This book was released on 2010 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Integrating Cover Crops and Herbicides for Horseweed Conyza Canadensis L Cronq Management Prior to Soybean Glycine Max L Merr written by Austin Sherman and published by . This book was released on 2019 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Glyphosate Tolerance of Horseweed Conyza Canadensis L Cronq Accessions from Kentucky written by Thatsaka Saphangthong and published by . This book was released on 2008 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book FIELD EMERGENCE OF HORSEWEED Conyza Canadensis L Cronq AND CONTROL UTILIZING TILLAGE AND HERBICIDES written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Horseweed has been documented in 70 countries and 40 different crops around the world and is listed as being a problem weed in no-till production systems. Horseweed has developed resistance to many herbicide modes of action including glycine. Field experiments were conducted from 2004 to 2006 in the Mississippi Delta to evaluate the field emergence of horseweed and most effective treatment programs for its control. Field emergence of horseweed was observed occurring primarily in the fall of the year, September through early November, when temperatures were between 15.6 to 23.4 C with later flushes occurring from late January through early April with temperatures ranging from 5.2 to 16 C. Tillage in September followed by herbicide in March gave 100% control of horseweed across all locations. Glyphosate + 2,4-D and glyphosate + dicamba were the best glyphosate-based treatments and provided 90% or better horseweed control 4 WAT both years. Glufosinate-based burndowns provided 81 to 97% horseweed control and soybean yields were generally similar with all glufosinate-based programs.

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 Horseweed Conyza Canadensis l Cronq Management in No tillage Soybean Production written by Joseph A. Bruce and published by . This book was released on 1989 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Emergence and Control of Horseweed Conyza Canadensis written by Joseph D. Bolte and published by . This book was released on 2015 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Horseweed (Conyza canadensis L. Cronq) traditionally has been viewed as a winter annual. However, farmers report increased problems managing horseweed that emerges in the spring. Horseweed emergence was documented fall through summer using 12 biotypes collected across Missouri. In 2013- 2014, averaged across populations, 31.8 and 68.7% of total emergence occurred in the spring at Columbia and Portageville in untreated sub-plots, respectively. In 2014-2015, 95.9 and 51.8% of the total emergence occurred in the spring at Columbia and Portageville, respectively. With spring and summer emergence, control of horseweed can be difficult, especially for biotypes that have developed resistance to post emergence (POST) herbicides. Over a two year period, horseweed was treated with multiple herbicide modes of action in a burndown application. Cloransulam plus sulfentrazone, dicamba, 2,4-D, glufosinate, paraquat and saflufenacil resulted in up to greater than 91% control by 35 DAT. Flumioxazin, metribuzin, linuron and glyphosate never resulted in greater than 70% control. Control with growth regulators was also determined on 10 to 20 cm; 20 to 30 cm; and 30 to 40 cm horseweed. Dicamba resulted in a 10.6, 18.5 and 20.4% increase in control compared to 2,4-D on 10 to 20 cm; 20 to 30 cm; and 30 to 40 cm horseweed, respectively. Because horseweed resistance to herbicides is a growing concern, 40 horseweed biotypes were treated with an I50 dose of dicamba. Plant response ranged from 45.7 to 83.5% control.

Download or read book Field Emergence of Horseweed Conyza Canadensis L Cronq and Control Utilizing Tillage and Herbicides written by Thomas William Eubank and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Horseweed has been documented in 70 countries and 40 different crops around the world and is listed as being a problem weed in no-till production systems. Horseweed has developed resistance to many herbicide modes of action including glycine. Field experiments were conducted from 2004 to 2006 in the Mississippi Delta to evaluate the field emergence of horseweed and most effective treatment programs for its control. Field emergence of horseweed was observed occurring primarily in the fall of the year, September through early November, when temperatures were between 15.6 to 23.4 C with later flushes occurring from late January through early April with temperatures ranging from 5.2 to 16 C. Tillage in September followed by herbicide in March gave 100% control of horseweed across all locations. Glyphosate + 2,4-D and glyphosate + dicamba were the best glyphosate-based treatments and provided 90% or better horseweed control 4 WAT both years. Glufosinate-based burndowns provided 81 to 97% horseweed control and soybean yields were generally similar with all glufosinate-based programs.