NC State Extension Publications

Introduction

Trade Name: Sedgehammer Common Name: halosulfuron Formulation: 75% DG

Uses

Postemergence control of annual and perennial sedges (yellow and purple nutsedge, and kyllinga) in established landscape woody ornamentals and turfgrass. Around ornamental landscape plants Sedgehammer should be applied as a directed spray.

Amount of Active Ingredient Amount by Formulation
75% DF
Per Acre 0.031 to 0.062 lb ai 0.67 to 1.3 oz
Per 1,000 sq. ft. 0.9 grams per gallon

Major Weeds Controlled

Yellow nutsedge, purple nutsedge, green kyllinga, and annual sedges. Some seedling broadleaf weeds may also be controlled including eclipta, galinsoga and others.

Major Weeds Not Controlled

Most annual and perennial grasses and broadleaves such as spurge, dandelions lambsquarters, and oxalis are not controlled.

For Best Results

Apply in late spring or early summer to when nutsedge plants are 4 to 6 inches tall and growing vigorously. Add non-ionic surfactant when using the 75% DF formulation. The 5% formulation has surfactant included in the formulation. Repeat the application in 6 weeks. Do not exceed two applications per year.

Cautions and Precations

Around ornamentals, use only as a directed application to established woody plants. Contact with the foliage of ornamentals should be avoided. Injury has been reported on several woody ornamental species including arborvitae, hemlock, and taxus. Over the top applications to ornamentals has caused injury to many species. Do not apply to herbaceous perennials or bedding plants. Do not use on container-grown ornamentals.

Residual Activity

At recommended rates, about 6 to 8 weeks of weed control can be expected.

Volatility and Leaching Potential

Nonvolatile. Halosulfuron is mobile in soils, and the amount of leaching is influenced organic matter, with less leaching occurring in soils with greater organic matter content.

Symptoms and Mode of Action

Inhibits the enzyme acetolactate synthase (ALS), responsible for the production of certain amino acids. Symptoms take several weeks to develop and include general stunting, chlorosis, and necrosis of the growing points. HRAC Group B; WSSA Group 2.

Additional Information

Worker Protection Standards REI: 12 hours
PPE: coveralls, chemical resistant gloves, shoes plus socks
Manufacturer: Gowan EPA Reg. # 81880-1-10163

Author:

Professor of Weed Science, Extension Specialist & Department Extension Leader
Horticultural Science

Publication date: Aug. 24, 2016

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