scholarly journals Glyphosate Resistance Confirmation and Field Management of Red Brome (Bromus rubens L.) in Perennial Crops Grown in Southern Spain

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 535
Author(s):  
José G. Vázquez-García ◽  
Patricia Castro ◽  
Hugo E. Cruz-Hipólito ◽  
Teresa Millan ◽  
Candelario Palma-Bautista ◽  
...  
Keyword(s):  
Weed Management ◽  
Shikimic Acid ◽  
Southern Spain ◽  
Integrated Weed Management ◽  
Fresh Weight ◽  
Perennial Crops ◽  
Resistance Factors ◽  
Bromus Rubens ◽  
Scientific Report ◽  
Postemergence Herbicides

The excessive use of the herbicide glyphosate on annual and perennial crops grown in Southern Spain has caused an increase in resistant weed populations. Bromus rubens has begun to spread through olive and almond cultivars due to low glyphosate control over these species, whereas previously it had been well controlled with field dose (1080 g ae ha−1). Characterization using Simple Sequence Repeat (SSR) markers confirmed the presence of B. rubens collected in Andalusia. A rapid shikimic acid accumulation screening showed 17 resistant (R) populations with values between 300 and 700 µg shikimate g−1 fresh weight and three susceptible (S) populations with values between 1200 and 1700 µg shikimate g−1 fresh weight. In dose–response experiments the GR50 values agreed with previous results and the resistance factors (RFs: GR50 R/GR50 S (Br1)) were between 4.35 (Br9) and 7.61 (Br19). Foliar retention assays shown no differences in glyphosate retention in both R and S populations. The tests carried out in a resistant field (Br10) demonstrated the control efficacy of pre-emergence herbicides since flazasulfuron in the tank mix with glyphosate had up to 80% control 15 to 120 days after application (DAA) and grass weed postemergence herbicides, such as propaquizafop + glyphosate and quizalofop + glyphosate, had up to 90% control 15 to 90 DAA. Results confirm the first scientific report of glyphosate-resistant B. rubens worldwide; however, the use of herbicides with another mode of action (MOA) is the best tool for integrated weed management.

scholarly journals Resistance Evolution to EPSPS Inhibiting Herbicides in False Barley (Hordeum murinum) Harvested in Southern Spain

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 992 ◽  
Author(s):  
José G. Vázquez-García ◽  
Patricia Castro ◽  
Joel Torra ◽  
Ricardo Alcántara-de la Cruz ◽  
Rafael De Prado
Keyword(s):  
Weed Management ◽  
Shikimic Acid ◽  
Southern Spain ◽  
Integrated Weed Management ◽  
Ps Ii ◽  
Resistance Evolution ◽  
Hordeum Murinum ◽  
Sites Of Action ◽  
Chemical Strategies ◽  
R Factors

A failure of the EPSPS-inhibiting herbicide glyphosate to control several populations of Hordeum murinum subsp. leporinum (or H. murinum) occurred in southern Spain after more than fifteen applications in both crop (olive, orchards, and citrus) and non-crop (dry areas, roadsides and ditches) areas. Eight out of 18 populations studied were resistant (R) to glyphosate with R factors higher than four based on GR50. These populations also had the highest values of LD50 and the lowest levels of shikimic acid accumulation. Two adjuvants tested increased glyphosate efficacy in both susceptible (S) and R populations thanks to better spray foliar retention. Moreover, PS I-, PS II-, and ACCase-inhibiting herbicides, in pre- or post-emergence, proved to be the best chemical alternatives with different sites of action (SoA) to control both S and glyphosate-R populations. This study represents the first report worldwide of glyphosate resistance in H. murinum found in very different crop and non-crop areas from southern Spain. To design chemical strategies to implement integrated weed management programs for glyphosate-R H. murinum, both adjuvants and herbicides with alternative SoA as well as application timings should be considered.

scholarly journals New Case of False-Star-Grass (Chloris distichophylla) Population Evolving Glyphosate Resistance

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 377 ◽  
Author(s):  
José G. Vázquez-García ◽  
Sajedeh Golmohammadzadeh ◽  
Candelario Palma-Bautista ◽  
Antonia M. Rojano-Delgado ◽  
José A. Domínguez-Valenzuela ◽  
...  
Keyword(s):  
Weed Management ◽  
Chemical Control ◽  
Shikimic Acid ◽  
Dry Weight ◽  
Glyphosate Resistance ◽  
Integrated Weed Management ◽  
Resistance Level ◽  
Susceptible Population ◽  
First Case

Chloris distichophylla, suspected of glyphosate resistance (GR), was collected from areas of soybean cultivation in Rio Grande do Sul, Brazil. A comparison was made with a susceptible population (GS) to evaluate the resistance level, mechanisms involved, and control alternatives. Glyphosate doses required to reduce the dry weight (GR50) or cause a mortality rate of 50% (LD50) were around 5.1–3 times greater in the GR population than in the GS population. The shikimic acid accumulation was around 6.2-fold greater in GS plants than in GR plants. No metabolized glyphosate was found in either GR or GS plants. Both populations did not differ in the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) basal activity or in vitro inhibition of EPSPS activity by glyphosate (I50). The maximum glyphosate absorption was observed at 96 hours after treatment (HAT), which was twofold higher in the GS plants than in the GR plants. This confirms the first case of glyphosate resistance in C. distichophylla. In addition, at 96 HAT, the GS plants translocated more 14C-glyphosate than the GR ones. The best options for the chemical control of both C. distichophylla populations were clethodim, quizalofop, paraquat, glufosinate, tembotrione, diuron, and atrazine. The first case of glyphosate resistance in C. distichophylla was due to impaired uptake and translocation. Chemical control using multiple herbicides with different modes of action (MOA) could be a tool used for integrated weed management (IWM) programs.

scholarly journals Optimizing Weed Management for the New Super-Forage Moringa oleifera

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1055
Author(s):  
Itai Shulner ◽  
Evyatar Asaf ◽  
Zohar Ben-Simhon ◽  
Miri Cohen-Zinder ◽  
Ariel Shabtay ◽  
...  
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Moringa Oleifera ◽  
Integrated Weed Management ◽  
Fresh Weight ◽  
Safety Level ◽  
Wide Range ◽  
Safe Control ◽  
New Crop ◽  
Moringa Oleifera Lam

Moringa oleifera Lam. (moringa hereafter) is cultivated as a new summer super-forage field crop in Israel, yet no weed control protocol has been developed for it. The objective of the study was to develop an integrated weed management (IWM) practice for the moringa agro-system in arid and semi-arid regions like the Mediterranean basin. We tested various herbicides applied pre (PRE) and post (POST) crop emergence and cultivation methods for weed control, with an emphasis on crop safety. The PRE herbicides were the most effective and safe control mean. Their application resulted in minor (<5%) crop fresh weight reductions and weed cover area, compared with the control. The POST herbicides were also effective, yet their crop safety level was lower and non-consistent in some treatments. Generally, the finger weeder was less effective than the herbicide treatments and caused higher fresh weight reduction. However, this means was more effective when applied at earlier stages. Management and environmental conditions had a high impact on the moringa growth; hence, these aspects should be considered. Our results show the potential use of different herbicides and non-chemical tools and set the basis for a future IWM protocol for moringa. The wide range of options offered here can ensure economic and environmentally viable solutions for this new crop.

scholarly journals Glyphosate Resistance in Amaranthus viridis in Brazilian Citrus Orchards

Agriculture ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 304
Author(s):  
Ricardo Alcántara-de la Cruz ◽  
Gabriel da Silva Amaral ◽  
Guilherme Moraes de Oliveira ◽  
Luiz Renato Rufino ◽  
Fernando Alves de Azevedo ◽  
...  
Keyword(s):  
Weed Management ◽  
Shikimic Acid ◽  
Main Tool ◽  
Glyphosate Resistance ◽  
Accumulation Rates ◽  
Fresh Weight ◽  
Susceptible Population ◽  
Site Type ◽  
Conyza Bonariensis ◽  
Citrus Orchards

Glyphosate is the main tool for weed management in Brazilian citrus orchards, where weeds, such as Conyza bonariensis and Digitaria insularis, have been found with resistance to this herbicide. Field prospections have allowed the identification of a possible new case of glyphosate resistance. In this work, the susceptibility levels to glyphosate on three Amaranthus viridis L. populations, with suspected resistance (R1, R2, and R-IAC), collected in citrus orchards from the São Paulo State, Brazil, as well as their accumulation rates of shikimic acid, were determined. The fresh weight of the susceptible population (S) was reduced by 50% (GR50) with ~30 g ea ha−1 glyphosate, while the GR50 values of the R populations were between 5.4 and 11.3 times higher than that for S population. The LD50 (herbicide dose to kill 50% of individuals of a weed population) values of the S population were ≤150 g ea ha−1 glyphosate, while the LD50 of the R populations ranged from 600 to 920 g ea ha−1. Based on the reduction of fresh weight and the survival rate, the R1 population showed the highest level of glyphosate resistance, which had GR50 and LD50 values of 248 and 918 g ea ha−1 glyphosate, respectively. The S population accumulated 240 µg shikimic acid at 1000 µM glyphosate, while the R1, R2, and R-IAC populations accumulated only 16, 43, and 33 µg shikimic acid, respectively (between 5.6 to 15 times less than the S population). Enzyme activity assays suggested that at least one target site-type mechanism was involved in resistance. This result revealed the first report of glyphosate resistance in A. viridis reported in the world.

scholarly journals Confirmation of Multiple Resistant Chloris radiata Population, Harvested in Colombian Rice Fields

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 496
Author(s):  
Verónica Hoyos ◽  
Guido Plaza ◽  
José G. Vázquez-Garcia ◽  
Candelario Palma-Bautista ◽  
Antonia M. Rojano-Delgado ◽  
...  
Keyword(s):  
Dose Response ◽  
Weed Management ◽  
Shikimic Acid ◽  
Lethal Dose ◽  
Dry Weight ◽  
Integrated Weed Management ◽  
Cross Resistance ◽  
Multiple Resistance ◽  
Visual Evaluation ◽  
Acid Accumulation

This paper reports the first C. radiata population with resistance to glyphosate and multiple resistance to the acetolactate synthase (ALS) inhibitor, imazamox. Two populations, one putative resistant (R) and one susceptible (S), were used in the studies. Dose–response experiments were performed to evaluate the resistance factor (RF). Shikimic acid accumulation, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) and ALS enzyme activities were studied together with chemical integrated weed management (adjuvants and alternative herbicides). The resistance to glyphosate and imazamox was confirmed based on the dry weight reduction, visual evaluation and survival. The results of dose–response curve assays showed for the R population intermedium RF for glyphosate (5.1 and 9.7 for amount of herbicide needed to reduce the dry weight by 50% GR50 and lethal dose of 50% LD50, respectively) and high RF for imazamox (34.9 and 37.4, respectively). The low shikimic acid accumulation in R population confirmed the glyphosate resistance. The glyphosate concentration which inhibited the EPSPS enzyme in 50% (I50) was approximately 20 times higher for R population than the S population, while the imazamox I50 in ALS enzyme for the R plants was 89 times greater than the S plants. In the chemical integrated weed management, the foliar retention and effectivity assays showed that the use of adjuvants improves the retention of glyphosate and imazamox, and the reduction in dry weight of weeds. The alternative herbicides study showed that the acetyl-CoA carboxylase (ACCase) inhibitors, paraquat and glufosinate, had better results for control in this species. However, poor control was observed with bispyribac-sodium, metsulfuron-methyl and quinclorac, indicating possible cross-resistance for ALS-inhibitors and also multiple resistance for auxinic herbicides (quinclorac). Nevertheless dose–response experiments are required to confirm this assumption.

scholarly journals Ecophysiological response of Sorghum halepense populations to reduced rates of nicosulfuron

2005 ◽  
Vol 40 (6) ◽  
pp. 541-547 ◽  
Author(s):  
Horacio Abel Acciaresi ◽  
Hugo Oscar Chidichimo
Keyword(s):  
Weed Management ◽  
Linear Models ◽  
Regression Coefficient ◽  
Co2 Exchange ◽  
Sorghum Halepense ◽  
Integrated Weed Management ◽  
Fresh Weight ◽  
Differential Performance ◽  
Ecophysiological Response ◽  
Reduced Rate

The control and regrowth after nicosulfuron reduced rate treatment of Johnsongrass (Sorghum halepense L. Pers.) populations, from seven Argentinean locations, were evaluated in pot experiments to assess if differential performance could limit the design and implementation of integrated weed management programs. Populations from humid regions registered a higher sensibility to reduced rates of nicosulfuron than populations from subhumid regions. This effect was visualised in the values of regression coefficient of the non-linear models (relating fresh weight to nicosulfuron rate), and in the time needed to obtain a 50% reduction of photosynthesis rate and stomatal conductance. The least leaf CO2 exchange of subhumid populations could result in a lower foliar absorption and translocation of nicosulfuron, thus producing less control and increasing their ability to sprout and produce new aerial biomass. The three populations from subhumid regions, with less sensibility to nicosulfuron rates, presented substantial difference in fresh weight, total rhizome length and number of rhizome nodes, when they were evaluated 20 week after treatment. In consequence, a substantial Johnsongrass re-infestation could occur, if rates below one-half of nicosulfuron labeled rate were used to control Johnsongrass in subhumid regions.

Broadleaf Weed Management in Grain Sorghum with Reduced Rates of Postemergence Herbicides

2005 ◽  
Vol 19 (2) ◽  
pp. 385-390 ◽  
Author(s):  
Enrique Rosales-Robles ◽  
Ricardo Sanchez-de-la-Cruz ◽  
Jaime Salinas-Garcia ◽  
Victor Pecina-Quintero
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Cost Reduction ◽  
Field Experiments ◽  
Grain Sorghum ◽  
Management Program ◽  
Integrated Weed Management ◽  
Crop Injury ◽  
Postemergence Herbicides ◽  
High Winds

2,4-D is the most widely used herbicide for weed control in grain sorghum in northern Tamaulipas, Mexico. Crop injury caused by 2,4-D drift to nontarget crops commonly occurs because of prevailing high winds. Field experiments were conducted from 2001 to 2003 to evaluate an integrated weed management program in grain sorghum with alternative postemergence herbicides to 2,4-D at registered and reduced rates. Bromoxynil applied at 480 (registered rate), 360, and 240 g/ha provided excellent broadleaf weed control when adequate rainfall occurred. Prosulfuron at 14.2 g/ha applied broadcast without cultivation provided excellent weed control and sorghum yield comparable with 28.5 g/ha (registered rate). This treatment represented a 32% cost reduction and 50% reduction in herbicide input compared with prosulfuron applied at registered rate without cultivation, and 31% cost reduction compared with 2,4-D at the registered rate (590 g ae/ha) plus cultivation, considered the commercial standard.

Integrated Weed Management in Oilseed Brassica

2016 ◽  
Vol 30 (4) ◽  
pp. 22
Author(s):  
Abhinandan Singh ◽  
Pankaj Kumar Ojha
Keyword(s):  
Weed Management ◽  
Integrated Weed Management

Fungal Phytotoxins in Sustainable Weed Management

2018 ◽  
Vol 25 (2) ◽  
pp. 268-286 ◽  
Author(s):  
Maurizio Vurro ◽  
Angela Boari ◽  
Francesca Casella ◽  
Maria Chiara Zonno
Keyword(s):  
Weed Management ◽  
Pathogenic Fungi ◽  
Mechanisms Of Action ◽  
Limiting Factors ◽  
Integrated Weed Management ◽  
Plant Pathogenic Fungi ◽  
Design Strategies ◽  
Disease Etiology ◽  
Chemical Structures ◽  
Toxic Metabolites

Fungal phytotoxins are natural secondary metabolites produced by plant pathogenic fungi during host–pathogen interactions. They have received considerable particular attention for elucidating disease etiology, and consequently to design strategies for disease control. Due to wide differences in their chemical structures, these toxic metabolites have different ecological and environmental roles and mechanisms of action. This review aims at summarizing the studies on the possible use of these metabolites as tools in biological and integrated weed management, e.g. as: novel and environmentally friendly herbicides; lead for novel compounds; sources of novel mechanisms of action. Moreover, the limiting factors for utilizing those metabolites in practice will also be briefly discussed.

Sign in / Sign up

Export Citation Format

Share Document