The label is the law. Rates and restrictions below are taken from the product labels listed under Sources. Your product's own label governs; read it before you mix or apply. Mixing calculator · Disclaimer
- Active ingredient
- Sethoxydim (CAS 74051-80-2)
- Chemical class
- Cyclohexanedione (a 'DIM'); WSSA Group 1 acetyl-CoA carboxylase (ACCase) inhibitor. Broadleaf plants are naturally resistant to this class.[2][1]
- Mode of action
- WSSA Group 1: ACCase inhibitors (cyclohexanediones, 'DIMs')[2][1]
- Signal word
- Segment II Herbicide: Warning[1]
Lawns it will kill
Use it only on centipedegrass and fine fescue lawns. The label warns that other turfgrasses suffer unacceptable injury or death, and it specifically says not to spray desirable tall fescue.[1]
Bermudagrass and bahiagrass appear on the label as weeds it controls, which is why it can clean grassy invaders out of shrub beds and groundcovers.[1]
Ornamentals and wildflowers
The label lists hundreds of tolerant trees, shrubs, bedding plants and wildflowers, but not every cultivar has been tested. Try it on a few plants first; in wildflower plantings, spray 4 to 6 weeks after emergence and before bloom.[1]
Where it is used
Spray small, actively growing grass weeds; letting them grow past the listed height prevents complete control. Stressed weeds from drought, flooding or temperature swings respond poorly.[1]
A crop oil concentrate or methylated seed oil is required for consistent control; the label says non-ionic surfactants may give unsatisfactory results.[1]
Don't mow centipedegrass or fine fescue within 7 days before or after spraying. Control improves if mowing waits 14 days, and grass weeds regrowing from mowed stubble may be controlled poorly.[1]
It is rainfast after one hour, and treated weeds die over about 3 weeks. Avoid spraying with oil adjuvants above 90°F at 60% humidity or higher, or any time it's over 100°F.[1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Segment II Herbicide[1] | BASF Agricultural Solutions US, LLC | 7969-398 | 18.0% | emulsifiable concentrate | Warning |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Segment II Herbicide | Ornamentals in residential and commercial landscapes, nurseries, wildflower plantings and noncrop areas | Crabgrass, goosegrass, foxtails, barnyardgrass, Japanese stiltgrass, annual ryegrass, bermudagrass, bahiagrass, quackgrass, johnsongrass and other listed grasses | 0.6–0.9 fl oz product per 1,000 sq ft[1] 0.6 fl oz for grasses up to 6 inches tall and 0.9 fl oz up to 12 inches; crabgrass and goosegrass should be no taller than 4 inches. Always add crop oil concentrate or methylated seed oil. |
| Segment II Herbicide | Centipedegrass and fine fescue lawns | Annual and perennial grass weeds (not annual bluegrass or rattail fescue) | 0.4–0.9 fl oz product per 1,000 sq ft[1] Seedling centipedegrass and fine fescue get 0.4 fl oz (1 pint per acre); mature centipedegrass up to 1.5 pints per acre; fine fescue up to 2.5 pints per acre. Seasonal caps are 2 pints per acre for seedling centipede and 3 pints otherwise. |
| Segment II Herbicide | Spot treatment of scattered grass weeds | Listed annual and perennial grasses | 1.3 fl oz product per gallon of water[1] A 1% solution, sprayed to wet, with 0.6 oz crop oil concentrate or 0.5 oz methylated seed oil per gallon. Don't spot treat on top of a broadcast application. |
Safety and environmental hazards
People
Signal word WARNING: causes substantial but temporary eye injury, causes skin irritation, and is harmful if absorbed through skin or swallowed. Handlers wear coveralls, chemical-resistant gloves and footwear, and protective eyewear.[1]
Pets
The label's hazard statements cover humans and domestic animals, and no one may enter treated areas until sprays have dried. Treated vegetation may not be used as pasture, hay, feed or forage.[1]
Bees and pollinators
The label has no direct bee warning but says it is toxic to plants and can harm the forage and habitat of pollinators next to the treated site if spray drifts.[1]
Fish and water
Toxic to aquatic organisms. Don't apply directly to water or where surface water is present, and don't contaminate water with washwater or rinsate.[1]
Common questions
- Will sethoxydim hurt my flowers and shrubs?
- It controls grasses only and has been applied to many ornamentals without injury, but the label asks you to test a small group of plants first and use a directed spray near untested species.[1][2]
- Can I use Segment II on a St. Augustine or bermuda lawn?
- No. The label limits turf use to centipedegrass and fine fescue and lists bermudagrass as a weed it kills.[1]
- Does sethoxydim kill nutsedge or broadleaf weeds?
- No. It doesn't control sedges or broadleaf weeds; the label's tank mix with Basagran T&O adds yellow nutsedge and broadleaf control in centipede and fine fescue.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Segment II Herbicide label, EPA Reg. No. 7969-398 (EPA-stamped, Sept. 12, 2024).” www3.epa.gov/pesticides/chem_search/ppls/007969-00398-20240912.pdf (accessed 2026-10-06)
- Weed Science Society of America, “Summary of Herbicide Mechanism of Action According to the Weed Science Society of America.” wssa.net/wp-content/uploads/WSSA-Mechanism-of-Action.pdf (accessed 2026-10-06)