scholarly journals Evolutionary epidemiology predicts the emergence of glyphosate resistance in a major agricultural weed

2019 ◽  
Vol 223 (3) ◽  
pp. 1584-1594 ◽  
Author(s):  
David Comont ◽  
Helen Hicks ◽  
Laura Crook ◽  
Richard Hull ◽  
Elise Cocciantelli ◽  
...  
Keyword(s):  
Glyphosate Resistance ◽  
Evolutionary Epidemiology ◽  
Agricultural Weed

scholarly journals Junglerice (Echinochloa colona) Control with Sequential Applications of Glyphosate and Clethodim to Dicamba

2021 ◽  
pp. 1-18
Author(s):  
Clay M. Perkins ◽  
Thomas C. Mueller ◽  
Lawrence E. Steckel
Keyword(s):  
Glyphosate Resistance ◽  
Time Of Application ◽  
Crop Fields ◽  
Row Crop ◽  
Excellent Control ◽  
Sequential Treatments

Abstract Junglerice is becoming more prevalent in Tennessee, Arkansas and Mississippi row crop fields. The evolution of glyphosate-resistant junglerice populations is one reason for the increase. Another possible explanation is that glyphosate and clethodim grass activity is being antagonized by dicamba. This question has led to research to examine if sequential applications alleviate antagonism observed with dicamba plus glyphosate and/or clethodim mixtures and determine if 24 h, 72 h or 168 h sequential treatments of those herbicides can improve junglerice control. Glyphosate + clethodim applications provided >90% junglerice control. The observed levels of antagonism varied by whether the location of the test was in the greenhouse or the field and the timing of applications. In the greenhouse, clethodim + dicamba provided excellent control while in the field the same treatment showed over a 30% reduction in junglerice control compared with clethodim alone. However, control was restored by using a mixture of glyphosate + clethodim without dicamba. The environment at the time of application and relative glyphosate-resistance (GR) level of the junglerice influenced the overall control of these sequential applications. Clethodim applied first followed by dicamba at 72 or 168 h, better control was observed compared with applying dicamba followed by clethodim. Overall, mixing glyphosate + clethodim provided the most complete junglerice control regardless of timing. These data confirm that leaving dicamba out of the spray tank will mitigate herbicide antagonism on junglerice control. These data would also indicate that avoiding dicamba and glyphosate mixtures will also improve the consistency of control with glyphosate-susceptible junglerice.

scholarly journals Monitoring the Utilization of Glyphosate Resistance Genes Based on Patent Analysis

2020 ◽  
Vol 598 ◽  
pp. 012076
Author(s):  
Xudong Jia ◽  
Fei Zhao ◽  
Yuyuan Zheng ◽  
Gaoyi Cao
Keyword(s):  
Resistance Genes ◽  
Glyphosate Resistance ◽  
Patent Analysis

scholarly journals Environmental cues affecting horseweed (Conyza canadensis) growth type and their sensitivity to glyphosate

Weed Science ◽  
2021 ◽  
pp. 1-35
Author(s):  
John A. Schramski ◽  
Christy L. Sprague ◽  
Eric L. Patterson
Keyword(s):  
Soil Moisture ◽  
Glyphosate Resistance ◽  
Single Parent ◽  
Environmental Cues ◽  
Conyza Canadensis ◽  
Growth Type ◽  
Susceptible Population ◽  
Water Imbibition ◽  
Growth Types ◽  
Winter Annual

Abstract Horseweed [Conyza canadensis (L.) Cronquist] is a facultative winter annual weed that can emerge from March to November in Michigan. Fall emerging C. canadensis overwinters as a rosette, while spring emerging C. canadensis skips the rosette stage and immediately grows upright upon emergence. In Michigan, primary emergence recently shifted from fall to spring/summer and therefore from a rosette to an upright growth type. Growth chamber experiments were conducted to determine 1) whether both C. canadensis growth types could originate from a single parent and 2) if common environmental cues can influence growth type. Variations in temperature, photoperiod, competition, shading, and soil moisture only resulted in the rosette growth type in four C. canadensis populations originating from seed collected from a single parent of the upright growth type. However, a vernalization period of four weeks following water imbibition, but prior to germination, resulted in the upright growth type. Dose-response experiments were conducted to determine whether glyphosate sensitivity differed between C. canadensis growth types generated from a single parent of the upright growth type. Upright type C. canadensis from known glyphosate-resistant populations ISB-18 and MSU-18 were four and three-fold less sensitive to glyphosate than their rosette siblings, respectively. Interestingly, differences in glyphosate sensitivity was not observed between growth types from the susceptible population. These results suggest that while C. canadensis populations shift from winter to summer annual lifecycles, concurrent increases in glyphosate resistance could occur.

scholarly journals Junglerice Control with Glyphosate and Clethodim as Influenced by Dicamba and 2,4-D Mixtures

2021 ◽  
pp. 1-28
Author(s):  
Clay M. Perkins ◽  
Thomas C. Mueller ◽  
Lawrence E. Steckel
Keyword(s):  
Personal Experience ◽  
Glyphosate Resistance ◽  
Herbicide Treatment

Abstract Junglerice has become a major weed in Mid-south US and other areas. Glyphosate resistance has been documented in junglerice populations and is part of the reason for the increase in its prevalence. However, reduced junglerice control with glyphosate + dicamba and clethodim + dicamba mixtures has been observed in many production fields where glyphosate resistance has not yet evolved. Therefore, research was conducted assessing reduced junglerice control with glyphosate and clethodim when applied with dicamba. Adding dicamba to the spray tank with glyphosate reduced junglerice control by 27%. Adding dicamba to the spray tank with clethodim reduced junglerice control by 11%. The use of TTI nozzles reduced junglerice control an additional 8% compared to applications with an AIXR nozzle. When a drift reduction agent (DRA) was added to dicamba mixtures with glyphosate or clethodim, junglerice control was reduced 36%. Junglerice control was similar with the glyphosate + dicamba treatment compared to the glyphosate + 2,4-D mixture. There was no interaction between nozzles and herbicide treatment. Regardless of herbicide treatment junglerice control was always lower when applied with the ultra-course TTI nozzle. Many applicators in Tennessee prefer to make one application of glyphosate + dicamba in a mixture to save time (Authors personal experience). These results show that the addition of dicamba to glyphosate or clethodim applied with labeled nozzles and a DRA results in reduced junglerice control and should be avoided.

scholarly journals Glyphosate Resistance in Perennial Ryegrass (Lolium perenneL.) is Associated with a Fitness Penalty

Weed Science ◽  
2016 ◽  
Vol 64 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Marcos Yanniccari ◽  
Martín Vila-Aiub ◽  
Carolina Istilart ◽  
Horacio Acciaresi ◽  
Ana M. Castro
Keyword(s):  
Perennial Ryegrass ◽  
Water Availability ◽  
Field Experiments ◽  
Seed Mass ◽  
Selection Effect ◽  
Glyphosate Resistance ◽  
Shoot Biomass ◽  
Seed Number ◽  
Fitness Costs ◽  
Weed Species

The net selection effect of herbicides on herbicide-resistance traits in weeds is conditioned by the fitness benefits and costs associated with resistance alleles. Fitness costs play an important evolutionary role preventing the fixation of adaptive alleles and contributing to the maintenance of genetic polymorphisms within populations. Glyphosate is widely used in world agriculture, which has led to the evolution of widespread glyphosate resistance in many weed species. The fitness of glyphosate-resistant and -susceptible perennial ryegrass plants selected from within a single population were studied in two field experiments conducted during 2011 and 2012 under different soil water availability. Glyphosate-resistant plants showed a reduction in height of 12 and 16%, leaf blade area of 16 and 33%, shoot biomass of 45 and 55%, seed number of 33 and 53%, and total seed mass of 16 and 5% compared to glyphosate-susceptible plants in 2011 and 2012, respectively. The reduction in seed number per plant resulted in a 40% fitness cost associated with the glyphosate-resistance trait in perennial ryegrass. Fitness costs of glyphosate-resistant plants were expressed under both conditions of water availability. These results could be useful for designing management strategies and exploiting the reduced glyphosate-resistant perennial ryegrass fitness in the absence of glyphosate selection.

scholarly journals A double EPSPS gene mutation endowing glyphosate resistance shows a remarkably high resistance cost

2017 ◽  
Vol 40 (12) ◽  
pp. 3031-3042 ◽  
Author(s):  
Heping Han ◽  
Martin M. Vila-Aiub ◽  
Adam Jalaludin ◽  
Qin Yu ◽  
Stephen B. Powles
Keyword(s):  
Gene Mutation ◽  
High Resistance ◽  
Glyphosate Resistance ◽  
Epsps Gene ◽  
Resistance Cost

Guidelines for Mapping Assessments of Agricultural Weed Problems

PANS ◽  
1978 ◽  
Vol 24 (1) ◽  
pp. 67-72 ◽  
Author(s):  
B. A. Auld
Keyword(s):  
Agricultural Weed

A Survey of Glyphosate-Resistant Waterhemp (Amaranthus rudis) in Missouri Soybean Fields and Prediction of Glyphosate Resistance in Future Waterhemp Populations Based on In-Field Observations and Management Practices

2013 ◽  
Vol 27 (4) ◽  
pp. 656-663 ◽  
Author(s):  
Kristin K. Rosenbaum ◽  
Kevin W. Bradley
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Glyphosate Resistance ◽  
Continuous Cropping ◽  
Field Observations ◽  
Weed Species ◽  
Herbicide Treatment ◽  
Amaranthus Rudis

A survey of soybean fields containing waterhemp infestations was conducted just prior to harvest in 2008 and 2009 to determine the frequency and distribution of glyphosate-resistant waterhemp in Missouri, and to determine if there are any in-field parameters that may serve as indicators of glyphosate resistance in this species in future crop production systems. Glyphosate resistance was confirmed in 99 out of 144, or 69%, of the total waterhemp populations sampled, which occurred in 41 counties of Missouri. Populations of glyphosate-resistant waterhemp were more likely to occur in fields with no other weed species present at the end of the season, continuous cropping of soybean, exclusive use of glyphosate for several consecutive seasons, and waterhemp plants showing obvious signs of surviving herbicide treatment compared to fields characterized with glyphosate-susceptible waterhemp. Therefore, it is suggested that these four site parameters, and certain combinations of these parameters, serve as predictors of glyphosate resistance in future waterhemp populations.

Role of absorption and translocation in the mechanism of glyphosate resistance in horseweed (Conyza canadensis)

Weed Science ◽  
2005 ◽  
Vol 53 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Clifford H. Koger ◽  
Krishna N. Reddy
Keyword(s):  
Glyphosate Resistance ◽  
Conyza Canadensis

scholarly journals Population genomic datasets describing the post-vaccine evolutionary epidemiology of Streptococcus pneumoniae

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Nicholas J. Croucher ◽  
Jonathan A. Finkelstein ◽  
Stephen I. Pelton ◽  
Julian Parkhill ◽  
Stephen D. Bentley ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Population Genomic ◽  
Evolutionary Epidemiology
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