Managing glyphosate resistance in Australian cotton farming: Modelling shows how to delay evolution and maintain long-term population control

Thornby, David, Werth, Jeff and Walker, Steven (2013) Managing glyphosate resistance in Australian cotton farming: Modelling shows how to delay evolution and maintain long-term population control. Crop and Pasture Science, 64 8: 780-790. doi:10.1071/CP13109

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Author Thornby, David
Werth, Jeff
Walker, Steven
Title Managing glyphosate resistance in Australian cotton farming: Modelling shows how to delay evolution and maintain long-term population control
Journal name Crop and Pasture Science   Check publisher's open access policy
ISSN 1836-0947
Publication date 2013-01-01
Year available 2013
Sub-type Article (original research)
DOI 10.1071/CP13109
Open Access Status DOI
Volume 64
Issue 8
Start page 780
End page 790
Total pages 11
Place of publication Collingwood, VIC Australia
Publisher C S I R O Publishing
Language eng
Subject 1102 Cardiovascular Medicine and Haematology
1110 Nursing
Abstract Glyphosate resistance is a rapidly developing threat to profitability in Australian cotton farming. Resistance causes an immediate reduction in the effectiveness of in-crop weed control in glyphosate-resistant transgenic cotton and summer fallows. Although strategies for delaying glyphosate resistance and those for managing resistant populations are qualitatively similar, the longer resistance can be delayed, the longer cotton growers will have choice over which tactics to apply and when to apply them. Effective strategies to avoid, delay, and manage resistance are thus of substantial value. We used a model of glyphosate resistance dynamics to perform simulations of resistance evolution in Sonchus oleraceus (common sowthistle) and Echinochloa colona (awnless barnyard grass) under a range of resistance prevention, delaying, and management strategies. From these simulations, we identified several elements that could contribute to effective glyphosate resistance prevention and management strategies. (i) Controlling glyphosate survivors is the most robust approach to delaying or preventing resistance. High-efficacy, high-frequency survivor control almost doubled the useful lifespan of glyphosate from 13 to 25 years even with glyphosate alone used in summer fallows. (ii) Two non-glyphosate tactics in-crop plus two in-summer fallows is the minimum intervention required for long-term delays in resistance evolution. (iii) Pre-emergence herbicides are important, but should be backed up with non-glyphosate knockdowns and strategic tillage; replacing a late-season, pre-emergence herbicide with inter-row tillage was predicted to delay glyphosate resistance by 4 years in awnless barnyard grass. (iv) Weed species' ecological characteristics, particularly seed bank dynamics, have an impact on the effectiveness of resistance strategies; S. oleraceus, because of its propensity to emerge year-round, was less exposed to selection with glyphosate than E. colona, resulting in an extra 5 years of glyphosate usefulness (18 v. 13 years) even in the most rapid cases of resistance evolution. Delaying tactics are thus available that can provide some or many years of continued glyphosate efficacy. If glyphosate-resistant cotton cropping is to remain profitable in Australian farming systems in the long-term, however, growers must adapt to the probability that they will have to deal with summer weeds that are no longer susceptible to glyphosate. Robust resistance management systems will need to include a diversity of weed control options, used appropriately.
Keyword Cotton
Echinochloa colona
Herbicide Resistance
Sonchus oleraceus
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Queensland Alliance for Agriculture and Food Innovation
Official 2014 Collection
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Citation counts: TR Web of Science Citation Count  Cited 4 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 4 times in Scopus Article | Citations
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Created: Tue, 03 Dec 2013, 10:39:18 EST by System User on behalf of Qld Alliance for Agriculture and Food Innovation