Abstract
The increased availability and high adoption rate of glyphosate-tolerant crops have selected for several glyphosate-resistant weed species. The response of representative weed species to glyphosate was assessed to provide insights and tools for optimizing glyphosate use for economic, agronomic and environmental reasons. Anoda cristata, Chenopodium album, Digitaria sanguinalis, Eleusine indica and Portulaca oleracea were grown outdoors in pots containing commercial potting medium. An increasing dose of glyphosate was applied to these species at three growth stages. Weed response was evaluated visually compared to the nontreated control and shoot dry weights were recorded. Fecundity was also determined. Based on visual evaluations, the dose of glyphosate required to attain 90% control of the species tested exhibited an application rate margin up to 28.5-fold compared to recommended rate, denoting a potential for rate optimization. Except for A. cristata, the recommended dose of glyphosate could be reduced by 30%–60% and still achieve 90% or greater control. The order of species sensitivity, based on effective dose 50 (ED50 )values, was E. indica > C. album > D. sanguinalis > P. oleracea > A. cristata. The ratio of ED90/ED50 was constant, indicating that increasing the glyphosate dose 8.7-fold would reduce weed biomass 1.8-fold. In most cases, the fecundity-avoidance biomass threshold (i.e., the maximum allowable weed biomass for herbicide application in order to prevent weed seed production and dispersal) for glyphosate was below the ED90 value. Complimentary measures such as fecundity-avoidance biomass threshold will improve herbicide evaluation procedures and preserve the effectiveness of herbicides, including glyphosate, on sensitive species, an important issue particularly when action to reduce herbicide resistance development is highly required.
| Original language | English (US) |
|---|---|
| Article number | 851 |
| Journal | Agronomy |
| Volume | 9 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 5 2019 |
| Externally published | Yes |
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Keywords
- Differential sensitivity
- Dose response curves
- Fecundity-avoidance threshold rate
- Herbicide efficacy
- Logistic regression
- Non-linear modeling
- Weed-size specific rate
ASJC Scopus subject areas
- Agronomy and Crop Science
Cite this
Response of annual weeds to glyphosate : Evaluation and optimization of application rate based on fecundity-avoidance biomass threshold criterion. / Leguizamon, Eduardo S.; Ferrari, German; Williams, Martin M.; Burgos, Nilda R.; Travlos, Ilias; Korres, Nicholas E.
In: Agronomy, Vol. 9, No. 12, 851, 05.12.2019.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Response of annual weeds to glyphosate
T2 - Evaluation and optimization of application rate based on fecundity-avoidance biomass threshold criterion
AU - Leguizamon, Eduardo S.
AU - Ferrari, German
AU - Williams, Martin M.
AU - Burgos, Nilda R.
AU - Travlos, Ilias
AU - Korres, Nicholas E.
PY - 2019/12/5
Y1 - 2019/12/5
N2 - The increased availability and high adoption rate of glyphosate-tolerant crops have selected for several glyphosate-resistant weed species. The response of representative weed species to glyphosate was assessed to provide insights and tools for optimizing glyphosate use for economic, agronomic and environmental reasons. Anoda cristata, Chenopodium album, Digitaria sanguinalis, Eleusine indica and Portulaca oleracea were grown outdoors in pots containing commercial potting medium. An increasing dose of glyphosate was applied to these species at three growth stages. Weed response was evaluated visually compared to the nontreated control and shoot dry weights were recorded. Fecundity was also determined. Based on visual evaluations, the dose of glyphosate required to attain 90% control of the species tested exhibited an application rate margin up to 28.5-fold compared to recommended rate, denoting a potential for rate optimization. Except for A. cristata, the recommended dose of glyphosate could be reduced by 30%–60% and still achieve 90% or greater control. The order of species sensitivity, based on effective dose 50 (ED50 )values, was E. indica > C. album > D. sanguinalis > P. oleracea > A. cristata. The ratio of ED90/ED50 was constant, indicating that increasing the glyphosate dose 8.7-fold would reduce weed biomass 1.8-fold. In most cases, the fecundity-avoidance biomass threshold (i.e., the maximum allowable weed biomass for herbicide application in order to prevent weed seed production and dispersal) for glyphosate was below the ED90 value. Complimentary measures such as fecundity-avoidance biomass threshold will improve herbicide evaluation procedures and preserve the effectiveness of herbicides, including glyphosate, on sensitive species, an important issue particularly when action to reduce herbicide resistance development is highly required.
AB - The increased availability and high adoption rate of glyphosate-tolerant crops have selected for several glyphosate-resistant weed species. The response of representative weed species to glyphosate was assessed to provide insights and tools for optimizing glyphosate use for economic, agronomic and environmental reasons. Anoda cristata, Chenopodium album, Digitaria sanguinalis, Eleusine indica and Portulaca oleracea were grown outdoors in pots containing commercial potting medium. An increasing dose of glyphosate was applied to these species at three growth stages. Weed response was evaluated visually compared to the nontreated control and shoot dry weights were recorded. Fecundity was also determined. Based on visual evaluations, the dose of glyphosate required to attain 90% control of the species tested exhibited an application rate margin up to 28.5-fold compared to recommended rate, denoting a potential for rate optimization. Except for A. cristata, the recommended dose of glyphosate could be reduced by 30%–60% and still achieve 90% or greater control. The order of species sensitivity, based on effective dose 50 (ED50 )values, was E. indica > C. album > D. sanguinalis > P. oleracea > A. cristata. The ratio of ED90/ED50 was constant, indicating that increasing the glyphosate dose 8.7-fold would reduce weed biomass 1.8-fold. In most cases, the fecundity-avoidance biomass threshold (i.e., the maximum allowable weed biomass for herbicide application in order to prevent weed seed production and dispersal) for glyphosate was below the ED90 value. Complimentary measures such as fecundity-avoidance biomass threshold will improve herbicide evaluation procedures and preserve the effectiveness of herbicides, including glyphosate, on sensitive species, an important issue particularly when action to reduce herbicide resistance development is highly required.
KW - Differential sensitivity
KW - Dose response curves
KW - Fecundity-avoidance threshold rate
KW - Herbicide efficacy
KW - Logistic regression
KW - Non-linear modeling
KW - Weed-size specific rate
UR - http://www.scopus.com/inward/record.url?scp=85076289556&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85076289556&partnerID=8YFLogxK
U2 - 10.3390/agronomy9120851
DO - 10.3390/agronomy9120851
M3 - Article
AN - SCOPUS:85076289556
VL - 9
JO - Agronomy
JF - Agronomy
SN - 2073-4395
IS - 12
M1 - 851
ER -