Influence of Sequential Herbicide Treatment, Herbicide Application Timing, and Mowing on Mugwort (Artemisia vulgaris) Control1

Abstract

Field trials were conducted during 1998 and 1999 to evaluate the effects of sequential herbicide treatment, herbicide application timing, and mowing on mugwort control. In the first field trial dicamba, triclopyr, clopyralid, picloram, metsulfuron, glufosinate, glyphosate, and the dimethylamine salt and the isooctyl ester of 2,4-D were applied to mugwort at 7-wk intervals to evaluate mugwort control after one, two, and three herbicide applications. When applied in three sequential applications, all herbicides except triclopyr, metsulfuron, and glufosinate provided at least 70% mugwort control 1 yr after treatment (YAT). At least 70% mugwort control was also achieved with just two sequential applications of dicamba, and only one application of picloram or clopyralid provided 100 and 84% mugwort control 1 YAT, respectively. In the second field trial the influence of application timing was investigated by applying herbicides to mugwort in the vegetative and the flowering stages of growth. Additionally, the effect of sequential mowing was evaluated by applying herbicides to mugwort regrowth after either one or two mowings. Generally, there was no difference in the level of mugwort control achieved with applications of these herbicides to mugwort in the flowering vs. the vegetative stage of growth. However, when averaged over all the herbicides included in these trials, two sequential mowings conducted before herbicide application enhanced the control of mugwort compared with either unmowed mugwort or mugwort that had been mowed once before herbicide application. Additionally, with the exception of picloram and glyphosate, all the herbicides evaluated in these trials provided higher mugwort control when applied to unmowed mugwort compared with mugwort that had been mowed only once. The results from these trials indicate that sequential herbicide treatment and sequential mowing are strategies that will enhance the control of mugwort when used with the majority of herbicides evaluated in these trials.Nomenclature: Clopyralid; 2,4-D dimethylamine salt; dicamba; 2,4-D isooctyl ester; glufosinate; glyphosate; metsulfuron; picloram; triclopyr; mugwort, Artemisia vulgaris L. #3 ARTVU.Additional index words: Cultural control, growth regulator herbicides, growth stage, nonselective herbicides, perennial weed control, regrowth, rhizome.Abbreviations: MAT, months after treatment; WAT, weeks after treatment; YAT, years after treatment.