Permanent Link: http://ufdc.ufl.edu/IR00003374/00001
 Material Information
Title: Managing Yellow and Purple Nutsedge in Florida Strawberry Fields
Physical Description: Fact Sheet
Creator: MacRae, Andrew W.
Publisher: University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication: Gainesville, Fla.
Acquisition: Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status: Published
General Note: "Original publication date May 2010.'
General Note: "HS1175"
 Record Information
Source Institution: University of Florida Institutional Repository
Holding Location: University of Florida
Rights Management: All rights reserved by the submitter.
System ID: IR00003374:00001

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Andrew W. MacRae2 1. This document is HS1175, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date May 2010. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. Andrew W. MacRae, assistant professor, UF/IFAS GCREC As growers continue their transition to methyl bromide alternatives, weed problems in strawberry fields will increase. Two of the more troublesome weeds that are anticipated are yellow and purple nutsedge (Figures 1 and 2). These weeds are perennial weeds that spread via underground roots called rhizomes and vegetatively produced structures known as tubers. Yellow nutsedge produces fewer but larger tubers than purple nutsedge. These tubers are produced in chains along the rhizomes and can remain dormant in the soil for several years. Fumigation targets these dormant tubers to maximize control of nutsedge. Nutsedge is well adapted for growth in plasticulture production systems. It is able to penetrate the majority of commercially used plastic mulches and produces large numbers of tubers by stealing the water and fertilizer intended for strawberry plants. Yellow and purple nutsedge inflorescence. It is important to keep any nutsedge population as small as possible, even to the point of having a zero-tolerance policy for any infestation. The grower should focus on year-round control to prevent wide-scale establishment of this weed. This involves selecting and correctly applying a good fumigant system, spot spraying, applying postharvest herbicides and/or fumigants, and implementing fallow period tillage, herbicide, and cover crop programs.


Managing Yellow and Purple Nutsedge in Florida Strawberry Fields 2 Yellow nutsedge emerging in a strawberry field. For areas of a field that have had nutsedge problems in the past, it is important to use a full fumigant system. Fumigant systems consisting of only 1,3-dichloropropene and/or chloropicrin will not provide satisfactory control of nutsedge. In long-term testing conducted in Georgia, the use of these systems actually increased the amount of nutsedge present in the field after four years of use. These systems may include a combination of Telone II and 100% chloropicrin or may come premixed, like Telone C35 and PicClor 60. Methyl bromide 50:50 provides good control of nutsedge, but will soon be phased out. Midas 50:50 provides good to excellent control, and the soon to be registered product Paladin Pic will provide excellent control. The use of a 3-Way system consisting of Telone II, chloropicrin, and KPam or Vapam will also provide good to excellent control. When using KPam or Vapam, a minicoulter rig provides the best control of nutsedge; however, if using drip applications, good control can be achieved if the grower uses two drip tapes to maximize coverage of the bed. Yellow and purple nutsedge will be a major factor in future fumigation decisions. Preventing this weed from obtaining a foothold may allow strawberry growers to use a reduced fumigant system, provided they are willing to spend time removing any escaped nutsedge populations from their production fields. If nutsedge is emerging through plastic mulch, it is important to spot spray a glyphosate product (Roundup, Touchdown HiTech, Glyfos Xtra, etc.) to kill the top growth as well as the tubers the plant is producing. Hand pulling will only result in removing the top growth, and repeat pulling may take all season before exhausting the root reserves of an established plant. At the end of the growing season, either an application of a fumigant in the drip tape or a postemergent application of a glyphosate product will be needed to reduce the population of nutsedge tubers present in the soil. The use of a fumigant can also help in reducing disease and nematode populations. Maintaining control of nutsedge requires an active management plan. The key is to break the rhizome of tubers so as to maximize nutsedge emergence at a time when control measures can be applied. For example, use tillage to break the rhizome and follow that with an application of glyphosate after the nutsedge shoots have emerged. After knocking back the population of nutsedge, seed a cover crop that will form a crop canopy quickly, preventing further emergence of nutsedge. Broadleaf cover crops tend to develop thicker crop canopies and are well suited to preventing light from reaching the soil surface, thus reducing nutsedge emergence and growth. Initial infestations of nutsedge will come from the edges of the field (Figure 3) and may obtain a foothold at the end of the rows where the fumigant has not been properly applied. It is important to maintain good weed management practices around the edges of the field. A little time spent from now on can help reduce the possibility of a nutsedge population increasing to the point where a full fumigant system will be required to keep the population below damaging levels.


Managing Yellow and Purple Nutsedge in Florida Strawberry Fields 3 Yellow nutsedge infestation from the edge of a strawberry field.