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COMMON COCKLEBUR (Xanthium strumarium)
with GROUP B/2 resistance: (ALS INHIBITORS)
Inhibition of acetolactate synthase ALS (acetohydroxyacid synthase AHAS)

MUTATION: ALANINE 205 to VALINE

Common cocklebur (Xanthium strumarium) is a dicot plant in the asteraceae family. A single amino acid substitution from Alanine 205 to Valine has led to resistance to ALS inhibitors as indicated in the table below.

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Common cocklebur

Chemistry	Example	Resistance
Imidazolinones	Imazethapyr	Intermediate Resistance < 10 fold
Pyrimidinylthiobenzoates	Bispyribac-Na	Intermediate Resistance < 10 fold
Sulfonylureas	Chlorsulfuron	Intermediate Resistance < 10 fold
Triazolopyrimidines	Chloransulam-methyl	Intermediate Resistance < 10 fold
Sulfonylaminocarbonyltriazolinone	Flucarbazone-Na	Not Determined

NOTES

REFERENCES

Woodworth, A. P., P. Bernasconi, M. Subramanian, and B. Rosen. (1996). A second naturally occurring point mutation confers broad-based tolerance to acetolactate synthase inhibitors. Plant Physiology , 111 () : S105.