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Preemergence and Postemergence Activities of the (R) and (S) Enantiomers of Haloxyfop

Published online by Cambridge University Press:  12 June 2017

B. Clifford Gerwick
Affiliation:
Agric. Products Res., The Dow Chem. Co., 2800 Mitchell Drive, Walnut Creek, CA 94598
Lucinda A. Jackson
Affiliation:
Agric. Products Res., The Dow Chem. Co., 2800 Mitchell Drive, Walnut Creek, CA 94598
Jack Handly
Affiliation:
Agric. Products Res., The Dow Chem. Co., 2800 Mitchell Drive, Walnut Creek, CA 94598
Nick R. Gray
Affiliation:
Agric. Products Res., The Dow Chem. Co., 2800 Mitchell Drive, Walnut Creek, CA 94598
John W. Russell
Affiliation:
Analytical Laboratories, The Dow Chem. Co., Midland, MI 48460

Abstract

The relative activities of (R) and (S) enantiomers of the methyl ester of haloxyfop were determined on annual grasses. Samples enriched in the (S) enantiomer were markedly less active than the (R) in petri dish evaluations and foliar applications. The pure (S) enantiomer was estimated by regression to be 1000-fold or less active than the (R). The activity of the (S) enantiomer was found to be equivalent to that of the (R) following preemergence applications. Isolation and characterization of haloxyfop from soil treated with the methyl ester of haloxyfop indicated inversion of the (S) enantiomer to the (R) enantiomer within 7 days. Field trials confirmed the differential activity of enantiomers applied postemergence and their equivalence when applied preemergence. These findings indicate that inversion of the (S) enantiomer to the (R) occurs in soil following preemergence applications.

Type
Physiology, Chemistry, and Biochemistry
Copyright
Copyright © 1988 by the Weed Science Society of America 

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References

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