Fact Sheets

Globally, the most important synthetic auxin resistant weeds are Kochia, Wild Radish, Corn poppy, and Wild Mustard. Although tall waterhemp and common lambsquarters are not widespread yet, they have the potential to become serious problems in the United States if they are not managed properly. To learn more about these weeds and how to manage synthetic auxin resistance, read the fact sheets below.

Synthetic Auxin Resistance

Synthetic auxins were the first highly effective, and selective organic herbicides. They have been used for over 60 years and are still being used extensively worldwide.

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Corn Poppy

Corn poppy is the most important broadleaf weed of winter wheat in southern Europe. Synthetic auxins, particularly 2,4‐D, have been used to control corn poppy in winter wheat for over 60 years.

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Kochia is a widespread annual weed known for its adaptability. Evidence of triazine resistance was detected as early as 1976 and to the ALS herbicides in the 1980's.

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Common lambsquarters is a rapidly growing summer annual weed found in many agricultural systems. Synthetic auxins have long been used for control of common lambsquarters throughout the world.

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Tall Waterhemp

Waterhemp is a significant weed of corn and soybean production in the Midwest of the US. Waterhemp has evolved resistance to six herbicide mechanisms of action.

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Wild Radish

Wild radish is the second most economically important weed of crops in Australia and a common weed of crops globally. It has evolved resistance to five mechanisms of action, the last being to synthetic auxins in 1999 in western Australia.

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Wild Mustard

Wild mustard is a common and serious weed of cereal production throughout the world. Populations of synthetic auxin resistant wild mustard were first found in cereal production in Manitoba, Canada in 1990. 

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