NC State Extension Publications


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Trade Name: Surflan Common Name: oryzalin Formulation: 4 AS

Limited Supplies - Future in Question

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Supplies of Surflan are limited. I cannot independently confirm the following but this is what I was told by a distributor. "The manufacturing facility was damaged and the active ingredient (oryzalin) is in very short supply. It is unclear oryzalin will be discontinued."

If you have supplies (or can purchase supplies) the labels are still valid and you can continue to use the Surflan you have. As I get additional information I will update this post.

Preemergence, surface-applied herbicide for control of annual grasses and many broadleaf weeds in established and newly planted field-grown ornamentals, groundcovers, bulbs, and some flowers as well as some container-grown ornamentals.

Amount of Active Ingredient Amount by Formulation
4 AS
Per Acre 2 to 4 lb 2 to 4 qt
Per 1,000 sq. ft. 1.5 to 3 oz

Major Weeds Controlled

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Annual grasses such as crabgrass, barnyardgrass, ryegrass, and johnsongrass (from seed). Broadleaf weeds controlled include pigweed, bittercress, common chickweed, spurge, and yellow woodsorrel. At the higher rate partial control of velvetleaf, groundsel, and smartweed is obtained.

Major Weeds Not Controlled

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Poor or erratic control of ragweed, groundsel, jimsonweed, galinsoga, nightshade, morningglory, prickly sida, horseweed, velvetleaf, dodder, and Venice mallow have been reported.

For Best Results

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Use as a directed spray where possible to avoid injury to growing points. Apply 12 inch of water to activate. May be shallowly cultivated (1 to 2 inches). May be tank mixed with other herbicides for improved broadleaf control following label directions.

Cautions and Precautions

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Do not repeat applications for at least 90 days. Use on several species is prohibited; see label for details. Do not use in conifer seedbeds or transplant beds. Severe injury to some conifers, including hemlock and Douglas fir, in transplant beds has been reported. Although labeled and safe on a wide number or woody and herbaceous ornamentals, injury has been observed on many herbaceous ornamentals, including salvia, russian sage, monarda, penstemon, blue fescue, Phlox panniculata, begonia, celosia, melampodium, and fountain grass. Stem girdling on some cultivars of Kurume-type azaleas and salvia have been observed. Rooted cuttings should be established two weeks or more before application. Over-dosing may result in crop injury.

Residual Activity

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In mineral soils: four to six months of weed control depending on rate, irrigation practices, weed spectrum, and soil type. In cool climates, residues from spring applications may inhibit the establishment and growth of fall-seeded grasses (such as oats or rye) used as a winter cover crop. In soilless substrates: shorter residuals of 6 to 8 weeks can be expected.

Volatility and Leaching Potential

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Little volatility or photodegradation. Stable on the soil surface for several weeks without incorporation. A limited amount of leaching may occur in coarse textured, low organic matter.

Symptoms and Mode of Action

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Inhibits root development by affecting cell division. No significant translocation occurs. Typical injury symptoms include swollen, stubby roots. These symptoms are most commonly seen on grasses. Symptoms from foliar applications may include “puckered” foliage, stunting or tip dieback. May cause girdling and stem swelling when used on young fir or spruce seedlings (see Root Inhibitors). Mode of Action Group 3

Additional Information

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Worker Protection Standards REI: 24 hours (with exceptions following irrigation, see label)
PPE: coveralls, chemical resistant gloves, shoes plus socks
Manufacturer: United Phosphorus EPA Reg. # 70506-44


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

Publication date: July 20, 2016
Revised: Jan. 29, 2021

Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by NC State University or N.C. A&T State University nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your local N.C. Cooperative Extension county center.

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