Multiple Herbicide–Resistant Italian Ryegrass [Lolium perenne L. spp. multiflorum (Lam.) Husnot] in California Perennial Crops: Characterization, Mechanism of Resistance, and Chemical Management

Weed Science ◽  
2018 ◽  
Vol 66 (6) ◽  
pp. 696-701 ◽  
Author(s):  
Caio A. C. G. Brunharo ◽  
Bradley D. Hanson
Keyword(s):  
Lolium Perenne ◽  
Dose Response ◽  
Weed Management ◽  
Management Practices ◽  
Field Experiments ◽  
Italian Ryegrass ◽  
Perennial Crop ◽  
Management Options ◽  
Herbicide Resistant ◽  
Chemical Management

AbstractItalian ryegrass [Lolium perenne L. spp. multiflorum (Lam.) Husnot] is a troublesome weedy species in many regions of California. Its control has been chiefly dependent on herbicides due to their effectiveness and practicality and, as result, herbicide-resistant populations have been selected. Poor control of a population of L. multiflorum with paraquat was recently reported in a prune orchard in Hamilton City, CA. A series of experiments were carried out to characterize the response of this population to several POST herbicides, study the mechanisms of resistance, and investigate alternative chemical management options in tree crops. A known susceptible (S) and the suspected resistant population (PRHC) were subjected to greenhouse dose–response experiments with clethodim, fluazifop-P-butyl, glufosinate, glyphosate, paraquat, pyroxsulam, rimsulfuron, and sethoxydim. A 310-bp fragment of the EPSPS gene containing position 106 was sequenced from PRHC and S. Field experiments were carried out in a prune orchard with PRE herbicides commonly used by perennial crop growers in California. Greenhouse dose–response experiments confirmed that PRHC is resistant to paraquat, as well as multiply resistant to clethodim and glyphosate. The EPSPS gene of PRHC is heterozygous for glyphosate resistance at position 106, where one allele exhibited proline substituted by serine and the other by alanine. Field experiments with PRE herbicides indicated that tank mixes containing indaziflam and flumioxazin can provide adequate L. multiflorum control up to 150 d after treatment. Poor weed management practices, such as overreliance on a single site of action, have frequently been associated with the selection of herbicide-resistant L. multiflorum populations around the world, and adequate herbicide-resistance management programs are necessary for growers to maintain economic sustainability even after evolution of herbicide-resistant weeds in their fields.

A Midsouthern Consultant’s Survey on Weed Management Practices in Soybean

2017 ◽  
Vol 32 (2) ◽  
pp. 116-125 ◽  
Author(s):  
Lauren M. Schwartz-Lazaro ◽  
Jason K. Norsworthy ◽  
Lawrence E. Steckel ◽  
Daniel O. Stephenson ◽  
Mandy D. Bish ◽  
...  
Keyword(s):  
Cover Crops ◽  
Weed Management ◽  
Management Practices ◽  
Palmer Amaranth ◽  
Italian Ryegrass ◽  
Time Constraints ◽  
Primary Concern ◽  
Protoporphyrinogen Oxidase ◽  
Herbicide Resistant ◽  
Southeast Missouri

AbstractSoybean consultants from Arkansas, Louisiana, southeast Missouri, Mississippi, and Tennessee were surveyed in 2016 to assess weed management practices and the prevalence of herbicide-resistant weeds in midsouthern U.S. soybean production. The consultants surveyed represented 13%, 28%, 8%, 16%, and 5% of the total soybean area planted in Arkansas, Louisiana, southeast Missouri, Mississippi, and Tennessee, respectively. Of the total scouted area, 78% of the consultants said their growers planted glyphosate-resistant soybean in 2016, with 18% planting glufosinate-resistant (LibertyLink®), primarily due to familiarity with and cost of the technology. Although 94% of the consultants determined that glufosinate was most effective on killing Palmer amaranth, the primary concern associated with controlling herbicide-resistant weeds was the associated cost, followed by return profit and time constraints. Palmer amaranth, morningglory species, horseweed, barnyardgrass, and Italian ryegrass were the five most problematic weeds in soybean across the five states. Palmer amaranth was the most problematic and important weed in each state individually. The increased concern (77% of consultants) with this species was attributed to the rising concern with and occurrence of protoporphyrinogen oxidase–resistant Palmer amaranth. Consultants were of the opinion that more research was needed on cover crops and the new traited technologies in order to improve weed management in soybean.

Changes in the Prevalence of Weed Species in the Major Agronomic Crops of the Southern United States: 1994/1995 to 2008/2009

Weed Science ◽  
2012 ◽  
Vol 60 (2) ◽  
pp. 145-157 ◽  
Author(s):  
Theodore M. Webster ◽  
Robert L. Nichols
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Regional Scale ◽  
Palmer Amaranth ◽  
Italian Ryegrass ◽  
Management Tool ◽  
Weed Species ◽  
Herbicide Resistant ◽  
Resistant Cultivars ◽  
Weed Flora

Changes in the weed flora of cropping systems reflect the impacts of factors that create safe sites for weed establishment and facilitate the influx and losses to and from the soil seedbank. This analysis of the annual surveys of the Southern Weed Science Society documents changes in the weed flora of the 14 contiguous southern states since the advent of transgenic, herbicide-resistant crops. In 1994 and 2009, the top five weeds in corn were morningglories, Texas millet, broadleaf signalgrass, johnsongrass, and sicklepod; in this same period Palmer amaranth, smartweeds, and goosegrass had the greatest increases in importance in corn. In cotton, morningglories and nutsedges were among the top five most troublesome weeds in 1995 and 2009. Palmer amaranth, pigweeds, and Florida pusley were also among the five most troublesome species in 2009; the weeds with the largest increases in importance in cotton were common ragweed and two species with tolerance to glyphosate, Benghal dayflower and Florida pusley. In soybean, morningglories, nutsedges, and sicklepod were among the top five weed species in 1995 and 2009. Two species with glyphosate resistance, Palmer amaranth and horseweed, were the second and fourth most troublesome weeds of soybean in 2009. In wheat, the top four weeds in 2008 were the same as those in 1994 and included Italian ryegrass, wild garlic, wild radish, and henbit. Crop production in the southern region is a mosaic of various crop rotations, soil types, and types of tillage. During the interval between the surveys, the predominant change in weed management practices in the region and the nation was the onset and rapid dominance of the use of glyphosate in herbicide-resistant cultivars of corn, cotton, and soybean. Because of the correspondence between the effects of glyphosate on the respective weed species and the observed changes in the weed flora of the crops, it is likely the very broad use of glyphosate was a key component shaping the changes in weed flora. Only eight of the top 15 most troublesome weeds of cotton and soybean, the crops with the greatest use of glyphosate, were the same in 1995 and 2009. In contrast, in corn and wheat where adoption of glyphosate-resistant cultivars lags or is absent, 12 of the 15 most troublesome weeds were the same in 1994 and 2008. These findings show on a regional scale that weeds adapt to recurrent selection from herbicides, currently the predominant weed management tool. Future research should seek methods to hinder the rapid spread of herbicide-tolerant and evolution of herbicide-resistant weed species. As new tools are developed, research should focus on ways to preserve the efficacy of those tools through improved stewardship.

scholarly journals Management Options for Multiple Herbicide–Resistant Corn Poppy (Papaver rhoeas) in Spain

Weed Science ◽  
2017 ◽  
Vol 65 (2) ◽  
pp. 295-304 ◽  
Author(s):  
Jordi Rey-Caballero ◽  
Aritz Royo-Esnal ◽  
Jordi Recasens ◽  
Ignacio González ◽  
Joel Torra
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Integrated Management ◽  
Management Strategies ◽  
Initial Density ◽  
Integrated Weed Management ◽  
Management Options ◽  
Herbicide Resistant ◽  
Winter Cereals ◽  
Tribenuron Methyl

Corn poppy is the most widespread broadleaf weed infesting winter cereals in Europe. Biotypes that are resistant (R) to both 2,4-D and tribenuron-methyl have evolved in recent decades, thus complicating their chemical control. In this study, field experiments at two locations over three seasons were conducted to evaluate the effects of different weed management strategies on corn poppy resistant to 2,4-D and tribenuron-methyl, including crop rotations, delayed sowing and different herbicide programs. After 3 yr, all integrated weed management (IWM) strategies reduced the initial density of corn poppy, although the most successful strategies were those which either included a suitable crop rotation (sunflower or field peas), or had a variation in the herbicide application timing (early POST or combining PRE or early POST and POST). The efficacy of IWM strategies differed between both locations, possibly due to different population dynamics and the genetic basis of herbicide resistance. Integrated management of multiple herbicide–resistant corn poppy is necessary in order to reduce selection pressure by herbicides, mitigate the evolution of new R biotypes, and reduce the weed density in highly infested fields.

Sumatran Fleabane (Erigeron sumatrensis) Resistant to PSI-Inhibitor Herbicides and Physiological Responses to Paraquat

Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Jéssica F. L. Leal ◽  
Amanda dos S. Souza ◽  
Junior Borella ◽  
André Lucas S. Araujo ◽  
Ana Claudia Langaro ◽  
...  
Keyword(s):  
Dose Response ◽  
Weed Management ◽  
Crop Production ◽  
Antioxidant Enzyme Activities ◽  
Multiple Resistance ◽  
Fast Recovery ◽  
Continuous Growth ◽  
Herbicide Resistant ◽  
Paraquat Resistance ◽  
Resistance To Herbicides

Abstract Herbicide-resistant weed management is one of the greatest agricultural challenges in crop production. Thus, the quick identification of resistant-herbicide weeds is extremely important for management. This study aimed to evaluate resistance to PSI-inhibitor herbicides (diquat) of Sumatran Fleabane [(Erigeron sumatrensis (Retz.) E.Walker)] and physiological response to paraquat application. The research was conducted with two E. sumatrensis biotypes, one susceptible and the other with multiple resistance to herbicides from five different modes of action (glyphosate, paraquat, diuron, saflufenacil, and 2,4-D). A dose-response assay was carried out to evaluate herbicide resistance to diquat in paraquat-resistant E. sumatrensis biotype. The enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), hydrogen peroxide (H2O2) content, and chlorophyll a fluorescence were measured in both biotypes after paraquat (400 g ai ha−1) application. The dose-response assay confirmed resistance of E. sumatrensis to diquat with resistance factor levels of 26-fold and 6-fold for LD50 and GR50 values, respectively, compared with the susceptible biotype. The accumulation of H2O2 occurred faster in the paraquat-susceptible biotype than in the resistant ones. Paraquat treatment caused an increase in SOD and APX activity in the susceptible biotype, but antioxidant enzyme activities were unaffected by paraquat in the resistant one at 5 hours after application (HAA). Chlorophyll a fluorescence increased along the first 4 HAA in both resistant and susceptible biotypes. However, at 24 HAA the resistant biotype showed a decline in fluorescence close to untreated plants while susceptible one died, which can be used to diagnose paraquat resistance at 24 HAA. There is confirmed resistance to diquat in a paraquat-resistant E. sumatrensis biotype. The paraquat-resistant biotype does not induce antioxidative enzymes, as a possible mechanism of resistance to paraquat, but shows a fast recovery of photosynthesis and continuous growth when subjected to paraquat, while the paraquat-susceptible biotype does not survive.

Impact of weed management practices on soil biological activity in corn and soybean field crops in Québec (Canada)

2020 ◽  
pp. 1-10
Author(s):  
Émile Samson-Brais ◽  
Marc Lucotte ◽  
Matthieu Moingt ◽  
Gilles Tremblay ◽  
Serge Paquet
Keyword(s):  
Biological Activity ◽  
Weed Management ◽  
Management Practices ◽  
Field Experiments ◽  
Soil Functions ◽  
Soybean Field ◽  
Soil Biological Activity ◽  
Field Crops ◽  
Fda Hydrolysis ◽  
Sampling Times

Repeated applications and combination of glyphosate-containing herbicides (GCH) with other herbicides are two weed management practices (WMP) used to compensate for GCH decreasing efficiency impacts in field crops. These practices may have serious impacts on soil functions because GCH affect soil biota and soil biological activity (SBA). Two field experiments, one with corn and one with soybean crops, were conducted during one growing season. SBA indicators, soil respiration (SR) and fluorescein diacetate (FDA) hydrolysis, were measured at two sampling times following six WMP. These WMP included one or two GCH applications (GCH alone or combined with other herbicides), applications of other herbicides only and mechanical weeding. WMP did not affect FDA neither for corn or soybean at either sampling times. In contrast, WMP affected SR in corn fields at both sampling times and SR in soybean field at the first sampling time. Repeating GCH applications and combining different herbicides led to lower SR, suggesting that these practices decreased SBA, whilst one single GCH application presented higher SR, suggesting that this practice stimulated SBA. Our study demonstrates that using GCH in combination with other herbicides or in multiple applications affects SBA in field conditions. Affecting soil functions and carbon cycle do bear serious weed management implications, and the choice of WMP should be taken into consideration to minimize their impacts on SBA for field crops sustainability.

Herbicide Timing and Rate Effects on Weed Management in Three Herbicide-Resistant Canola Systems

2004 ◽  
Vol 18 (4) ◽  
pp. 1006-1012 ◽  
Author(s):  
K. Neil Harker ◽  
George W. Clayton ◽  
John T. O'Donovan ◽  
Robert E. Blackshaw ◽  
F. Craig Stevenson
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Management Practices ◽  
Integrated Weed Management ◽  
Weed Biomass ◽  
Herbicide Resistant ◽  
Leaf Stage ◽  
Rate Effects ◽  
Herbicide Timing ◽  
Weed Removal

Herbicide-resistant canola dominates the canola market in Canada. A multiyear field experiment was conducted at three locations to investigate the effect of time of weed removal (two-, four-, or six-leaf canola) and herbicide rate (50 or 100% recommended) in three herbicide-resistant canola systems. Weeds were controlled in glufosinate-resistant canola (GLU) with glufosinate, in glyphosate-resistant canola (GLY) with glyphosate, and in imidazolinone-resistant canola (IMI) with a 50:50 mixture of imazamox and imazethapyr. Canola yields were similar among the three canola cultivar–herbicide systems. Yields were not influenced by 50 vs. 100% herbicide rates. Timing of weed removal had the greatest effect on canola yield, with weed removal at the four-leaf stage giving the highest yields in most cases. Percent dockage was often greater for GLU and IMI than for GLY. In comparison with the other treatments, dockage levels doubled for GLU after application at 50% herbicide rates. The consistency of monocot weed control was usually greater for GLY than for GLU or IMI systems. However, weed biomass data revealed no differences in dicot weed control consistency between IMI and GLY systems. Greater dockage and weed biomass variability after weed removal at the six-leaf stage or after low herbicide rates suggests higher weed seed production, which could constrain the adoption of integrated weed management practices in subsequent years.

Competitiveness of Herbicide-Resistant Waterhemp (Amaranthus tuberculatus) with Soybean

Weed Science ◽  
2018 ◽  
Vol 66 (6) ◽  
pp. 729-737 ◽  
Author(s):  
Thomas R. Butts ◽  
Bruno C. Vieira ◽  
Débora O. Latorre ◽  
Rodrigo Werle ◽  
Greg R. Kruger
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Cropping Systems ◽  
Biomass Accumulation ◽  
Stem Diameter ◽  
The Other ◽  
Harvest Time ◽  
Herbicide Resistant ◽  
Amaranthus Tuberculatus ◽  
Soybean Plants

AbstractWaterhemp [Amaranthus tuberculatus(Moq.) J. D. Sauer] is a troublesome weed occurring in cropping systems throughout the U.S. Midwest with an ability to rapidly evolve herbicide resistance that could be associated with competitive disadvantages. Little research has investigated the competitiveness of differentA. tuberculatuspopulations under similar environmental conditions. The objectives of this study were to evaluate: (1) the interspecific competitiveness of three herbicide-resistantA. tuberculatuspopulations (2,4-D and atrazine resistant [2A-R], glyphosate and protoporphyrinogen oxidase [PPO]-inhibitor resistant [GP-R], and 2,4-D, atrazine, glyphosate, and PPO-inhibitor susceptible [2AGP-S]) with soybean [Glycine max(L.) Merr.]; and (2) the density-dependent response of eachA. tuberculatuspopulation within a constant soybean population in a greenhouse environment.Amaranthus tuberculatuscompetitiveness with soybean was evaluated across five target weed densities of 0, 2, 4, 8, and 16 plants pot−1(equivalent to 0, 20, 40, 80, and 160 plants m−2) with 3 soybean plants pot−1(equivalent to 300,000 plants ha−1). At the R1 soybean harvest time, no difference in soybean biomass was observed acrossA. tuberculatuspopulations. AtA. tuberculatusdensities <8 plants pot−1, the 2AGP-S population had the greatest biomass and stem diameter per plant. At the R7 harvest time, the 2AGP-S population caused the greatest loss in soybean biomass and number of pods compared with the other populations at densities of <16 plants pot−1. The 2AGP-S population had greater early-season biomass accumulation and stem diameter compared with the otherA. tuberculatuspopulations, which resulted in greater late-season reduction in soybean biomass and number of pods. This research indicates there may be evidence of interspecific competitive fitness cost associated with the evolution of 2,4-D, atrazine, glyphosate, and PPO-inhibitor resistance inA. tuberculatus. Focus should be placed on effectively using cultural weed management practices to enhance crop competitiveness, especially early in the season, to increase suppression of herbicide-resistantA. tuberculatus.

scholarly journals Changes in Herbicide Use after Adoption of HR Canola in Western Canada

2011 ◽  
Vol 25 (3) ◽  
pp. 492-500 ◽  
Author(s):  
S. J. Smyth ◽  
M. Gusta ◽  
K. Belcher ◽  
P. W. B. Phillips ◽  
D. Castle
Keyword(s):  
Environmental Impact ◽  
Active Ingredient ◽  
Weed Management ◽  
Management Practices ◽  
Soil Management ◽  
Western Canada ◽  
Herbicide Resistant ◽  
Production Technologies ◽  
Time Required ◽  
Herbicide Use

This article examines the changes in herbicide use in relation to canola production in Western Canada, comparing 1995 and 2006. The commercialization and widespread adoption of herbicide-resistant (HR) canola has changed weed management practices in Western Canada. Before the introduction of HR canola, weeds were controlled by herbicides and tillage as the leading herbicides at that time required tillage to allow for soil incorporation of the herbicide. Much of the tillage associated with HR canola production has been eliminated as 64% of producers are now using zero or minimum tillage as their preferred form of crop and soil management. Additionally, there have been significant changes regarding the use and application of herbicides for weed control in canola. This research shows that when comparing canola production in 1995 and 2006, the environmental impact of herbicides applied to canola decreased 53%, producer exposure to chemicals decreased 56%, and quantity of active ingredient applied decreased 1.3 million kg. The cumulative environmental impact was reduced almost 50% with the use of HR herbicides. If HR canola had not been developed and Canadian canola farmers continued to use previous production technologies, the amount of active ingredient applied to control weeds in 2007 would have been 60% above what was actually applied.

Differential Response of Grain Sorghum Hybrids to Foliar-Applied Mesotrione

2009 ◽  
Vol 23 (1) ◽  
pp. 28-33 ◽  
Author(s):  
M. Joy M. Abit ◽  
Kassim Al-Khatib ◽  
David L. Regehr ◽  
Mitchell R. Tuinstra ◽  
Mark M. Claassen ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Dose Response ◽  
Field Experiments ◽  
Growing Season ◽  
Grain Sorghum ◽  
Differential Response ◽  
Visible Injury ◽  
Herbicide Resistant ◽  
Sorghum Production ◽  
Selection Of

The selection of herbicide-resistant weeds in grain sorghum production has prompted researchers to explore alternative herbicides to prevent, delay, and manage herbicide-resistant weed biotypes. Greenhouse and field experiments were conducted to evaluate the differential response of sorghum hybrids to POST application of mesotrione. In a greenhouse experiment, 85 sorghum hybrids were treated with 0, 52, 105, 210, and 315 g ai/ha mesotrione when plants were at the three- to four-leaf collar stage. Sorghum response ranged from susceptible to tolerant sorghum hybrids. ‘Pioneer 84G62’, ‘Pioneer 85G01’, and ‘Triumph TR 438’ were the three most susceptible, whereas ‘Dekalb DKS35-70’, ‘Frontier F222E’, and ‘Asgrow Seneca’ were the three most tolerant hybrids. One week after treatment (WAT), the mesotrione rate causing 50% visible injury ranged from 121 to 184 and 64 to 91 g/ha in the most tolerant and susceptible hybrids, respectively. Mesotrione dose–response studies were conducted under field conditions on four sorghum hybrids. One WAT, injury symptoms were greater (up to 23%) in Pioneer 85G01 than in Asgrow Seneca (< 14%). However, all plants appeared normal by the end of the growing season. In addition, sorghum yields were not reduced by mesotrione treatments as verified by correlation coefficient analysis.

Control of Volunteer Canola with Herbicides: Effects of Plant Growth Stage and Cold Acclimation

2006 ◽  
Vol 20 (2) ◽  
pp. 485-493 ◽  
Author(s):  
Anne Légère ◽  
Marie-Josée Simard ◽  
Eric Johnson ◽  
F. Craig Stevenson ◽  
Hugh Beckie ◽  
...  
Keyword(s):  
Cold Acclimation ◽  
Dose Response ◽  
Growth Stage ◽  
Field Experiments ◽  
Early Growth ◽  
Wheat Crop ◽  
Response Curves ◽  
Early Growth Stage ◽  
Herbicide Resistant ◽  
Phenoxy Herbicides

Phenoxy herbicides are frequently used to control volunteer canola populations. However, there have been claims that poor control could be due to cold acclimation of canola plants in the spring. The objective of this study was to determine whether cold acclimation or growth stage affected the response of canola volunteers to herbicides. In a growth room experiment, canola plants were prehardened and cold acclimated or were grown at 20/12 C and treated with one of six 2,4-D doses. Cold acclimation as achieved by this experiment affected upper and lower asymptotes of the dose–response curve but not the herbicide dose required to reduce canola weight by 50% relative to the nontreated control (GR50), indicating limited cold-related effects on canola tolerance to 2,4-D. Field experiments, conducted in the provinces of Québec and Saskatchewan, examined the effects of canola growth stage on the efficacy of 2,4-D, MCPA, and carfentrazone. Comparisons of the estimates from the dose–response curves confirmed that herbicide efficacy was consistently greater when canola plants were treated at an early growth stage, regardless of cultivar or herbicide used. The GR50estimates for canola plants treated at a later growth stage exceeded the recommended rates. Some canola plants grown as volunteers in a wheat crop survived 2,4-D or MCPA treatments at 0.5× and 1× rates and produced up to 148 seeds/m2. Efficient control of canola volunteers will be obtained when plants are sprayed at an early growth stage, but near-total control will be highly desirable in order to restrict seedbank buildup, particularly when dealing with canola cultivars with different herbicide-resistant traits.

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