Pest Management Science (2018) 74, 1089-1093

Judit Barroso, Jennifer A. Gourlie, Larry K. Lutcher, Mingyang Liu and Carol A. Mallory-Smith (2018)
Identification of glyphosate resistance in Salsola tragus in north-eastern Oregon
Pest Management Science 74 (5), 1089-1093
Abstract:
Background
Farmers in the low-rainfall region of eastern Oregon rely on repeated applications of non-selective herbicides, predominately glyphosate, to control Salsola tragus in no-till fallow systems. Reports of poor glyphosate effectiveness have increased in recent years. Reduced efficacy is often attributed to dust, water stress, or generally poor growing conditions during application. Inadequate control also may be the result of the evolution of glyphosate resistance. Therefore, studies were undertaken to determine if glyphosate-resistant S. tragus populations occur in Oregon.
Results
Results from dose–response studies confirmed glyphosate resistance in three of 10 Oregon Salsola tragus populations. The ratio I_50R/I_50S from dose–response curves was, on average, 3.1 for the relative dry biomass per plant and 3.2 for the % of surviving plants per pot in these three populations. Plant mortality at recommended glyphosate doses for the resistant populations was less than 30% 3 weeks after treatment.
Conclusions
Glyphosate resistance in S. tragus highlights the imperative need to diversify weed control strategies to preserve the longevity and sustainability of herbicides in semi-arid cropping systems of the Pacific Northwest.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Judit Barroso, Mingyang Liu

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Salsola tragus (weed)		U.S.A. (NW)