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 CONFIRMATION AND MANAGEMENT OF MULTIPLE RESISTANCE OF HORSEWEED Conyza Canadensis L Cronq TO GLYPHOSATE AND PARAQUAT written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Resistance to Glyphosate and Paraquat in Conyza Bonariensis and Conyza Canadensis from California Orchards written by Marcelo Luvizotto Moretti and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Conyza bonariensis and Conyza canadensis are weeds found in orchards and other areas of California. These species are problematic in orchards because of populations that have evolved resistance to glyphosate, and glyphosate and paraquat in the case of C. bonariensis. Due to the need for management of these resistant weeds, a series of greenhouse and field experiments were conducted to evaluate alternative herbicides for managing these populations. The herbicides glufosinate and the mixtures of glyphosate with saflufenacil and glyphosate with 2,4-D were effective in controlling susceptible, glyphosate-resistant, and glyphosate-paraquat-resistant populations of C. bonariensis, and thus could be used as a tool to mitigate the spread of the resistance. Although management options were in place, no information was available on the distribution of the multiple-resistant populations in the state. Distribution and presence of glyphosate and paraquat resistance was evaluated in field populations of both Conyza sp. throughout the Central Valley, as well as in accessions previously grouped into different genetic groups based on genetic population structure. Glyphosate-resistant Conyza sp. was commonly found in all surveyed areas. Glyphosate-paraquat resistance was confirmed in accessions from distinct genetic groups that were originally collected from three counties in the state: Merced, Fresno, and Kern Counties. One C. canadensis accession was confirmed to be glyphosate-paraquat-resistant. Resistance to paraquat was always associated with glyphosate resistance. Because multiple resistance was found across a wide geographical range and in accessions from distinct genetic groups, multiple-resistant Conyza sp. likely evolved independently several times in California. In the next phase of research, the mechanism of resistance in these Conyza populations was investigated. Using radiolabeled herbicides, the absorption and translocation of the glyphosate and paraquat was monitored over time in glyphosate-resistant, glyphosate-paraquat-resistant, and susceptible biotypes of both species. Resistance to glyphosate or paraquat was associated with reduced translocation of the herbicides in both Conyza sp. The mechanism of reduced translocation was hypothesized to be related to the sequestration of herbicides into the vacuoles probably through tonoplast transporters. To investigate genes that could be involved in the mechanism of resistance, a transcription study using real time PCR was performed. First, eight candidate reference genes were evaluated for their stability after stress with glyphosate or paraquat in both Conyza sp. The genes actin, heat-shock-protein 70, and cyclophilin were identified as stable under herbicide stress in both species. Second, transcription of two putative tonoplast transporters from the ATP binding cassette (ABC) transporter family, one putative cationic amino acid transporter (CAT), and 5-enolpyruvylshikimate-3-phosphatase synthase (EPSPS) genes were evaluated. No changes in the transcription of CAT or EPSPS genes were observed after herbicide treatments. Transcription of ABC transporters increased after herbicide treatment, but the changes could not be associated with resistant biotypes, but rather suggests a stress response. This work was the first study of glyphosate-paraquat resistance in Conyza sp., and the findings highlighted herein can advance the understanding on this matter.

Download or read book Control of Glyphosate Resistant Horseweed Conyza Canadensis with Saflufenacil and Tank mixture Partners written by Brock Steven Waggoner and published by . This book was released on 2010 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Field and labratory studies were conducted to determine the efficacy of saflufenacil alone and with mixture partners for burndown. Field studies were conducted in 2009 and 2010 to evaluate saflufenacil in mixtures with glyphosate, glufosinate, or paraquat for control of glyphosate-resistant (GR) horseweed prior to planting cotton. Saflufenacil and saflufenacil mixtures were applied 7 days before planting (DBP). Saflufenacil at 25 and 50 g ai ha-1 in mixture with all three non-selective herbicides provided similar GR horseweed control when compared to the current standard of glyphosate plus dicamba. Control of GR horseweed was also not different at the 25 and 50 g ai ha-1 of saflufenacil across all mixtures from the standard of glyphosate plus dicamba. Laboratory studies were initiated to determine the uptake and translocation of saflufenacil alone and when mixed with glyphosate and paraquat. It was found that glyphosate plus saflufenacil had a greater absorption of saflufenacil at 2 and 8 HAT. By 24 HAT there were not any differences between the amount of saflufenacil absorbed into GR horseweed between treatments. Translocation data also confirmed that the majority of saflufenacil stayed in the treated leaf at 72 HAT.

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 A Systems Approach to Conyza Canadensis Management written by Bryan P. Reeb and published by . This book was released on 2018 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Ohio, no-tillage soybean production, glyphosate, and acetolactate synthase inhibitor (ALS)-inhibiting herbicides are common components for management of horseweed. However, resistance to glyphosate was confirmed in Ohio in 2002, followed by multiple resistance to both ALS inhibitors and glyphosate in 2003. Field studies were conducted from the fall of 2009 through the summer of 2016 to develop strategies for management of horseweed populations with these types of resistance in no-tillage soybeans. The objectives were to: 1) determine the efficacy of fall-applied herbicides for management of horseweed emerging in the spring; 2) determine the effect of spring application timing and herbicide on the residual control of horseweed through mid-summer; and 3) determine the most effective herbicide program for soybeans resistant to glufosinate, glyphosate/dicamba, or to glyphosate/glufosinate/2,4-D.

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.

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 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 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 Factors Affecting Glyphosate Control of Horseweed Conyza Canadensis and Hairy Fleabane Conyza Bonariensis written by Loren Scott Scheufele and published by . This book was released on 2009 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impact of Automated Guidance for Mechanical Control of Herbicide Resistant Weeds in Corn written by Terry Griffin and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of herbicide weed control has been an integral part of farm management for several decades due to being an efficient and cost-effective alternative to mechanical weed control management. However, repeated use of broad spectrum herbicides has resulted in herbicide resistance in several weed species (Norsworthy et al., 2012). Although the indiscriminate use of herbicides has been linked to the quick and widespread adoption of herbicide resistant crop species (Fernandez-Cornejo et al., 2014), research indicates that herbicide resistance predated the introduction of bio-tech crops by several decades (WSSA, 2016). By the time that USDA began tracking the adoption of biotech soybean production in 2000, over half of US acreage were planted to herbicide-tolerant varieties and reached over 90% within 7 years (USDA NASS) (Figure 1). By 2013, 90% of corn and soybean acreage were planted to bio-tech cultivars including herbicide-tolerate only and stacked genes (Figure 1). Currently, 470 unique cases of herbicide resistance have been documented (Heap, 2016). Multiple herbicide-resistant weed species causes additional concern due to reduced herbicide options and increased weed control costs. Multiple herbicide resistance has been confirmed in economically important weeds including Palmer amaranth (Amaranthus palmeri) (Nandula et al. 2012), waterhemp (Amaranthus tuberculatus Sauer) (Bell et al., 2013), horseweed (Conyza canadensis L. Cronq.) (Davis et al. 2009), rigid ryegrass (Lolium rigidum Gaudim) (Owen et al. 2014), and kochia (Kochia scoparia (L.) Schrad.) (Foes et al. 1999) (see Heap, 2016, for more details on herbicide resistance weeds).

Download or read book Herbicide Resistance and World Grains written by Stephen B. Powles and published by CRC Press. This book was released on 2001-03-13 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by experts from across the globe, Herbicide Resistance and World Grains evaluates the weed and herbicide management systems in major world grain crops such as soybean, maize, rice, and canola. The book examines the impact of transgenic crops and new technology on resistance management. It provides background information and offers practical

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.