(Alopecurus aequalis)

Microtubule Assembly inhibitors (K1/3)

Shortawn Foxtail (Alopecurus aequalis) is a monocot weed in the Poaceae family.  In Japan this weed first evolved resistance to Group K1/3 herbicides in 2005 and infests Wheat, and Winter barley.   Group K1/3 herbicides are known as Microtubule Assembly inhibitors (Inhibition of Microtubule Assembly ).  Research has shown that these particular biotypes are resistant to trifluralin and they may be cross-resistant to other Group K1/3 herbicides.

The 'Group' letters/numbers that you see throughout this web site refer to the classification of herbicides by their site of action. To see a full list of herbicides and HRAC herbicide classifications click here.

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QUIK STATS (last updated Feb 04, 2016 )

Common NameShortawn Foxtail
SpeciesAlopecurus aequalis
GroupMicrotubule Assembly inhibitors (K1/3)
Situation(s)Wheat, and Winter barley
Contributors - (Alphabetically)Akira Uchino 
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Akira Uchino

Pest Manag Sci. 2012 Mar;68(3):422-9. doi: 10.1002/ps.2284. Epub 2011 Oct 3.
Mutation of alpha-tubulin genes in trifluralin-resistant water foxtail (Alopecurus aequalis).
Hashim S1, Jan A, Sunohara Y, Hachinohe M, Ohdan H, Matsumoto H.

Trifluralin-resistant biotypes of water foxtail (Alopecurus aequalis) have been identified in wheat fields from northern Kyushu, Japan. Water foxtail is a winter-annual grassy weed, causing substantial crop losses. This study reports on mutation in α-tubulin (TUA) genes from water foxtail, the site of action of trifluralin.
Two trifluralin-sensitive (S) Chikugo and Ukiha biotypes and four trifluralin-resistant (R) Asakura-1, Asakura-2, Tamana and Tosu biotypes of water foxtail were used for herbicide resistance analysis. R biotypes showed 5.7-30.7-fold trifluralin resistance compared with the S biotypes. No differences in the uptake and translocation of (14)C-trifluralin were observed between Chikugo (S) biotype and Asakura-1 (R) biotype. Most of the (14)C detected in the plant material was in the root tissue, and no substantial increases were noted in shoot tissues. Comparative TUA sequence analysis revealed two independent single amino acid changes: change of Val into Phe at position 202 in TUA1 and change of Leu into Met at position 125 in TUA3 in Asakura-1 biotype. In the Tamana (R) biotype, two amino acid changes of Leu to Phe at position 136 and Val to Phe at position 202 were observed in the predicted amino acid sequence of TUA1, compared with Chikugo (S) biotype.
The results provide preliminary molecular explanation for the resistance of water foxtail to trifluralin, a phenomenon that has arisen as a result of repeated exposure to this class of herbicide. This is the first report of α-tubulin mutation in water foxtail and for any Alopecurus species reported in the literature.

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Confirmation Tests

Greenhouse, and Laboratory trials comparing a known susceptible Shortawn Foxtail biotype with this Shortawn Foxtail biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.

Genetic studies on Group K1/3 resistant Shortawn Foxtail have not been reported to the site.  There may be a note below or an article discussing the genetics of this biotype in the Fact Sheets and Other Literature
Mechanism of Resistance

Studies on the mechanism of resistance of Group K1/3 resistant Shortawn Foxtail from Japan indicate that resistance is due to an altered target site.  There may be a note below or an article discussing the mechanism of resistance in the Fact Sheets and Other Literature
Relative Fitness

There is no record of differences in fitness or competitiveness of these resistant biotypes when compared to that of normal susceptible biotypes.  If you have any information pertaining to the fitness of Group K1/3 resistant Shortawn Foxtail from Japan please update the database.
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Weed Scientist
NARO Agricultural Research Center
3-1-1 Kannondai
Tsukuba, 305-8666, Ibaraki
Email Akira Uchino


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Japan have been instrumental in providing you this information. Particular thanks is given to Akira Uchino for providing detailed information.
Herbicide Resistant Shortawn Foxtail Globally
(Alopecurus aequalis)
Herbicide Resistant Shortawn Foxtail Globally
(Alopecurus aequalis)
Drag a column header and drop it here to group by that column
Herbicide Resistant Shortawn Foxtail Globally
(Alopecurus aequalis)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ChinaChina 2010 Wheat clodinafop-propargyl, and fenoxaprop-P-ethyl 9 ACCase inhibitors (A/1)
264Alopecurus aequalisShortawn Foxtail5524
2 ChinaChina 2014 Wheat fenoxaprop-P-ethyl, flucarbazone-sodium, mesosulfuron-methyl, nicosulfuron, penoxsulam, pinoxaden, and quizalofop-ethyl 9 Multiple Resistance: 2 Sites of Action
ACCase inhibitors (A/1)
ALS inhibitors (B/2)
264Alopecurus aequalisShortawn Foxtail10954
3 JapanJapan 2004 Spring Barley, and Wheat thifensulfuron-methyl, and trifluralin 25 Multiple Resistance: 2 Sites of Action
ALS inhibitors (B/2)
Microtubule Assembly inhibitors (K1/3)
264Alopecurus aequalisShortawn Foxtail5570
4 JapanJapan 2005 Wheat, and Winter barley trifluralin 25 Microtubule Assembly inhibitors (K1/3)
264Alopecurus aequalisShortawn Foxtail11018
5 JapanJapan 2006 Wheat thifensulfuron-methyl 25 ALS inhibitors (B/2)
264Alopecurus aequalisShortawn Foxtail11019
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