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Influence of Imazapyr on the Control of Pitted Morningglory (Ipomoea lacunosa) and Johnsongrass (Sorghum halepense) with Chlorimuron, Imazaquin, and Imazethapyr

Published online by Cambridge University Press:  12 June 2017

Dennis G. Riley
Affiliation:
Dep. Plant Pathol. Weed Sci., Mississippi State Univ., Mississippi State, MS 39762
David R. Shaw
Affiliation:
Dep. Plant Pathol. Weed Sci., Mississippi State Univ., Mississippi State, MS 39762

Abstract

Field experiments were conducted to evaluate postemergence combinations of imazethapyr, imazquin, or chlorimuron with low rates of imazapyr for Johnsongrass and pitted morningglory control. Imazapyr applied alone at rates up to 4 g ai/ha gave little or no control of either weed species. However, the addition of imazapyr to various rates of imazethapyr or imazaquin synergistically increased both johnsongrass and pitted morningglory control 8 weeks after treatment. The rates of imazethapyr or imazaquin required for significant enhancement of johnsongrass control were higher than those required for pitted morningglory control. No synergistic increases in control of either weed species were noted with mixtures of imazapyr and chlorimuron. Although not synergistic in every case, the mixtures of imazapyr at 4 g/ha with imazethapyr, imazaquin, or chlorimuron gave johnsongrass and pitted morningglory control equal to or better than the next higher rate of these herbicides applied alone. Imazapyr did not increase soybean injury or decrease yield provided by chlorimuron, imazaquin, or imazethapyr.

Type
Weed Control and Herbicide Technology
Copyright
Copyright © 1988 by the Weed Science Society of America 

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References

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