The occurrence of herbicide-resistant Avena fatua (wild oats) populations to ACCase-inhibiting herbicides in Ireland

Byrne, Ricky; Bhaskar, A Vijaya; Spink, John; Freckleton, Robert P.; Neve, Paul; Barth, Susanne

doi:10.15212/ijafr-2020-0127

Cited by 3 publications

(2 citation statements)

References 17 publications

(18 reference statements)

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“…multiflorum (Lam.) Husnot] in cereal fields in Ireland (Alwarnaidu Vijayarajan et al 2020Vijayarajan et al , 2021Byrne et al 2021;Vijayarajan et al 2022). Although the ACCase/ALS-inhibiting herbicides are usually not targeted to control P. annua in Ireland, the wet autumns and fewer preemergence spray opportunities and the loss of isoproturon registration in the European Union (EU) in 2017 resulted in more reliance on postemergence herbicides that also had activity on P. annua, raising the possibility of resistance development in non-target species.…”

Section: Introductionmentioning

confidence: 99%

Characterization of mesosulfuron-methyl + iodosulfuron-methyl and pyroxsulam–resistant annual bluegrass (Poa annua) in an annual cropping system

Alwarnaidu Vijayarajan,

Morgan,

Onkokesung

et al. 2023

Weed Sci

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Herbicide-resistant annual bluegrass (Poa annua L.) has become a problem in non-arable land areas. In arable fields, P. annua is frequently of lower priority in weed control programmes due to the variety of control options available and the relatively modest impact on crop yield than other species. In Ireland, postemergence herbicides are not primarily intended for P. annua control, but some herbicides, including acetolactate synthase (ALS)-inhibitor mesosulfuron-methyl + iodosulfuron-methyl, exhibit P. annua-activity. In this study, a suspected P. annua population (POAAN-R) that survived mesosulfuron-methyl + iodosulfuron-methyl at 0.75 of field-recommended rate was sampled from a wheat field in County Dublin, Ireland. Single-dose testing confirmed that the suspected POAAN-R had evolved resistance to mesosulfuron-methyl + iodosulfuron-methyl and additionally, to pyroxsulam (not registered in Ireland for P. annua control), but was sensitive to clethodim, glyphosate, pendimethalin and flufenacet. Dose-response experiments indicated that POAAN-R was more resistant (GR50 resistance index) to both mesosulfuron-methyl + iodosulfuron-methyl (47.8 times) and pyroxsulam (38.0 times) than sensitive POAAN-S and this was associated with the mutation at tryptophan (Trp)-574 in ALS protein. Malathion (a cytochrome P450 inhibitor) pre-treatment did not reverse POAAN-R resistance to mesosulfuron-methyl + iodosulfuron-methyl or pyroxsulam at field rate or above. The natural inherent mutation at isoleucine (Ile)-1781 in ACCase protein had no effect on both POAAN-R and POAAN-S sensitivity to clethodim. The glyphosate sensitivity of POAAN-R also corresponded with no known mutation in EPSPS protein. Based on field histories, poor early-season weed control coupled with intensive use of mesosulfuron-methyl + iodosulfuron-methyl (often at reduced rates) has unintentionally selected for ALS-inhibitor-resistant POAAN-R. This is the first report to characterize resistance in P. annua to ALS-mesosulfuron-methyl + iodosulfuron-methyl and pyroxsulam in an arable setting. There is an opportunity to effectively control POAAN-R using herbicides, but this needs a wide-ranging and varied approach, coupled with cultural/non-chemical practices.

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Section: Introductionmentioning

confidence: 99%

Characterization of mesosulfuron-methyl + iodosulfuron-methyl and pyroxsulam–resistant annual bluegrass (Poa annua) in an annual cropping system

Alwarnaidu Vijayarajan,

Morgan,

Onkokesung

et al. 2023

Weed Sci

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“…Since 2019, resistance to ACCase/ALS inhibitors via targetsite resistance (TSR) and/or non-target-site resistance (NTSR) has been documented in A. fatua, A. myosuroides and L. multiflorum in cereal fields in Ireland (Alwarnaidu Vijayarajan et al, 2020;Byrne et al, 2021;Alwarnaidu Vijayarajan et al, 2021). To date, knowledge of the resistance problem has been almost exclusively based on ad-hoc basis of testing suspect field populations, where herbicide control was inadequate.…”

Section: Introductionmentioning

confidence: 99%

Grass-weed challenges, herbicide resistance status and weed control practices across crop establishment systems in Ireland’s mild Atlantic climate

Vijayarajan

Fealy²,

Cook³

et al. 2022

Front. Agron.

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The challenges of grass-weed control in a mild Atlantic climate, added to by the use of non-inversion tillage and limited herbicide options necessitated on-farm knowledge acquisition on grass weeds in Ireland. We surveyed 103 farms from 2020 to 2021 of which, 62 were plough-based and 41 non-inversion tillage. The survey comprised a questionnaire to determine grower demographics, grass-weed challenges, and the adoption of integrated grass-weed control methods (IWM); a grid-square assessment of key grass weeds encountered in one or more cereal fields in both years using weed scores from 0 (absent) to 10 (total weed cover); with samples collected for herbicide-resistance testing. Across the 103 farms, Bromus spp., (62%) and Avena fatua (56%) were the most prevalent but with moderate resistance (8% acetolactate synthase (ALS)-resistant Bromus, 10% acetyl-CoA carboxylase (ACCase)-resistant A. fatua); Lolium multiflorum (13%) and Alopecurus myosuroides (16%) were found on fewer farms but with higher resistance levels (56% ACCase and/or ALS-resistant L. multiflorum, 43% ACCase/ALS-resistant A. myosuroides). Of those who adopted non-inversion tillage, a higher proportion of growers practiced crop rotation (88% cereal/non-cereal break or 83% alternate spring/winter-sown) and used cover crops (71%) than those ploughing (52-66% crop rotation or 19% cover crops), but herbicide use was similar in both systems. Despite higher levels of IWM practices, non-inversion tillage farms had higher weed scores (2.2 ± 0.2 or 3.8 ± 0.7) of B. sterilis and L. multiflorum than ploughing (1.2 ± 0.2 or 2.0 ± 0.7). Considering the complex resistance profile of high resistance-risk species, there is a need for urgent determination of and adoption of effective IWM across systems, specifically, non-inversion tillage. Most of the growers were aware of herbicide-resistant grass weeds (>80%) and most (>90%) used IWM practices (4 or more) to some extent. In our survey, non-inversion tillage farms tended to have younger growers with more formal education and larger farms. This is the first multi-component survey in Ireland establishing long-term monitoring of grass-weed challenges, grower characteristics and IWM practices.

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Study of molecular mechanisms of herbicide binding t o target proteins of weeds by in silico methods

Pamirsky,

Timkin,

Timofeev

et al. 2023

Rossijskaâ selʹskohozâjstvennaâ nauka

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The aim of this study was to study of the molecular mechanisms of herbicide binding (pinoxaden, quizalofop- P-tephuryl, prometryn, metribuzin, metsulfuron- methyl) to target proteins (acetyl- CoA carboxylase, acetolactate synthase, cytochrome P450, p-hydroxyphenylpyruvate dioxygenase) of the weed species growing in Siberia: wild oat Avena fatua (L.), wheatgrass Elymus repens (L.), amaranth Amaranthus retro exus (L.), common lamb's quarters Chenopodium album (L.), bristlegrass Setaria viridis (L.). The work was carried out in the Novosibirsk region in 2022-2023. Using bioinformatic methods, virtual three- dimensional complexes of pesticides and their targets were created. A new approach has been proposed to identify the parameters of the cavity of binding sites, which consists in combining the alignment method and machine learning technology. Docking of pesticides with targets was carried out. The calculation of the binding energy indicates a high degree of stability of the ligand- protein complexes. The in silico approach we proposed may be useful for elucidating the behavior of herbicides when bound to weed enzymes. This approach allows a deeper understanding of the mechanism of action and ecotoxicological aspects of the use of pesticides. The studied complexes of herbicides and proteins have a potential high stability due to the low binding energy with receptors, which varies from -5.60 to -13.24 kcal/mol. The binding energy value did not show a direct dependence on the number of amino acid residues of the ligand- binding site. In general, the study supplemented some aspects of the molecular mechanisms of binding herbicides to target proteins of weeds, however, a more in-depth study is required in order to localize critical amino acid points involved in the biological functions of target proteins.

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The occurrence of herbicide-resistant Avena fatua (wild oats) populations to ACCase-inhibiting herbicides in Ireland

Cited by 3 publications

References 17 publications

Characterization of mesosulfuron-methyl + iodosulfuron-methyl and pyroxsulam–resistant annual bluegrass (Poa annua) in an annual cropping system

Characterization of mesosulfuron-methyl + iodosulfuron-methyl and pyroxsulam–resistant annual bluegrass (Poa annua) in an annual cropping system

Grass-weed challenges, herbicide resistance status and weed control practices across crop establishment systems in Ireland’s mild Atlantic climate

Study of molecular mechanisms of herbicide binding t o target proteins of weeds by in silico methods

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