NC State Extension Publications

Introduction

Trade Name: Broadstar Common Name: flumioxazin Formulation: 0.25 G

Uses

Preemergence control of most annual broadleaf weeds and grasses in established container and field grown woody ornamentals.

Amount of Active Ingredient Amount by Formulation
0.25 G
Per Acre 0.375 lb 150 lb
Per 1,000 sq. ft. 3.5 lb
** Do not exceed 150 lb product/acre per treatment or 300 lb product (0.75 lb ai) per acre

Major Weeds Controlled

Most annual broadleaf weeds common in container and field grown nursery crops including: bittercress, spurge, woodsorrel, phyllanthus, groundsel, chickweed, morningglory, doveweed, horseweed, liverwort and others. Eclipta control has been good at some locations and fair at others. Acceptable control of crabgrass is achieved but control declines with reduced dose. Primarily used preemergence but cotyledon to one-leaf stage broadleaf weeds are often be controlled.

Major Weeds Not Controlled

Nutsedges are not controlled. Sometimes weak on pearlwort, chickweed, evening primrose, and annual grasses.

For Best Results

Apply before weeds emerge or after existing weeds have been removed. Irrigate immediately following treatment.

Cautions and Precautions

Do not apply over the top when ornamental plants have tender, young growth or injury and stunting may result. Apply to dry foliage. Applications to moist foliage will dramatically increase injury severity by allowing granules to adhere to crop foliage. Do not apply to herbaceous perennials or woody liners as severe injury has been reported on some species. Significant injury has been reported on plants with leaf architecture that holds granules or channels granules to the growing points (such as daylily, hosta, some grasses). Do not use in greenhouses or other enclosed structures. Use on non-bearing fruit trees only (plants that will not bear fruit for at least one year).

Residual Activity

Two to three months of annual broadleaf weed control. Somewhat less for annual grasses and eclipta.

Volatility and Leaching Potential

Moderately volatile but readily absorbed by soil organic matter. Leaching is not expected to be significant.

Symptoms and Mode of Action

The most common injury symptom is localized necrotic spots (contact burn) on leaves where granules adhere to the foliage. Symptoms are more severe when applied to moist foliage – including tip necrosis and dieback in particularly susceptible species such as hydrangea and ligustrum. Symptoms develop rapidly, within days. Herbicide is generally not systemic, but in some susceptible species young plants (e.g. wax myrtle and spiraea) development of red pigments in the main veins of leaves, suggests translocation. HRAC Group E; WSSA Group 14.

Additional Information

Worker Protection Standards REI: 12 hours
PPE: coveralls, chemical resistant gloves, shoes plus socks
Manufacturer: Valent EPA Reg. # 59639-128

Author:

Professor of Weed Science and Extension Specialist
Horticultural Science

Publication date: Nov. 20, 2014

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