Broadcast Applications of Glyphosate Control Nutsedge at a South Georgia Forest Tree Nursery
Nutsedge is a major weed problem in some southern forest tree nurseries. Although herbicides can control most weeds in nurseries, control of nutsedge is usually dependent on fumigation. The purpose of this study was to examine the effectiveness of broadcast applications of glyphosate for control of nutsedge. Single and multiple applications of glyphosate at 2.2 kg ai/ha greatly reduced the density of nutsedge shoots and viable tubers at a south Georgia forest tree nursery. The first application in June 1999 reduced nutsedge shoots by approximately 98%. Subsequent applications during September and October 1999 had no additional detectable effect. Although applications in August and September 2000 greatly reduced the amount of nutsedge in previously untreated areas, their effect did not appear to be as great as glyphosate applications during the first year. Rainfall before and after glyphosate applications, and plant age at the time of application may have influenced the level of nutsedge control in year two. Nutsedge shoots and viable tubers were reduced to near zero levels in plots treated over a 2 yr. period. The use of broadcast applications of glyphosate may be of value in developing a more cost-effective management program for nutsedge control in southern forest tree nurseries.