The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Deltamethrin (CAS 52918-63-5)
- Chemical class
- Synthetic pyrethroid: a human-made version of the natural pyrethrins found in chrysanthemum flowers.[1]
- Mode of action
- IRAC Group 3A: Sodium channel modulators (nerve action)[4]
- Signal words
- Suspend SC: Caution[2]
K-Othrine Dust Insecticide (formerly sold as DeltaDust): Caution[3]
How it works
Deltamethrin kills insects on contact or when they eat it by disrupting normal nervous system function.[1]
It is less toxic to mammals than to insects because of mammals' higher body temperature, larger body size and lower sensitivity to the chemical.[1]
Deltamethrin belongs to IRAC Group 3A, the sodium channel modulators, the same group as bifenthrin, permethrin and the natural pyrethrins; rotating to a different group number is the basic tool for slowing resistance.[4]
Choosing a rate
On the Suspend SC label, 0.25 fl oz per gallon gives a 0.01% spray for maintenance, 0.75 fl oz gives 0.03% for initial or clean-out treatments, and 1.5 fl oz gives 0.06% for severe infestations or longer residual control.[2]
Treatments may be repeated at 21-day intervals or as needed, and the label prohibits broadcast treatment of floors and use as a space spray.[2]
In the environment
Deltamethrin is broken down by microbes, light and water, and it persists longer in soils high in clay or organic matter; it is not likely to evaporate.[1]
Where it is used
Suspend SC is labeled indoors as a general surface, spot, crack-and-crevice or void treatment, and outdoors as a perimeter or residual spray, on turf, and on landscape ornamentals.[2]
K-Othrine Dust (formerly DeltaDust) is a ready-to-use dust applied into cracks and crevices, service ducts, false floors and ceilings, wall voids, and around electrical fittings and plumbing for residual control.[5]
For termites, carpenter ants and carpenter bees, the dust is applied into voids and channels in damaged wood and the spaces between wooden members; it does not replace a soil termite treatment.[5][3]
Products and registrations
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Suspend SC | Indoor surface, spot, crack and crevice, voids | Ants, bed bugs, cockroaches, spiders, fleas, ticks and other listed indoor pests | 0.25–1.5 fl oz per gal of water[2] 0.25 fl oz for maintenance, 0.75 for initial or clean-out service, 1.5 for severe infestations or longer residual. |
| Suspend SC | Outdoor residual spray and perimeter | Ants, spiders, occasional invaders, mosquitoes and other listed outdoor pests | 0.25–1.5 fl oz per 1,000 sq ft of surface[2] A per-area limit: if you spray more than 1 gallon over 1,000 sq ft, lower the amount per gallon. |
| Suspend SC | Lawns and turf (broadcast) | Ants, armyworms, chiggers, crickets, fleas, sod webworms, ticks and other listed turf pests | 0.4–0.6 fl oz per 1,000 sq ft[2] In at least 2 gallons of water per 1,000 sq ft. |
How to apply it, step by step
1. Protective gear
- The label requires no specific gear for general use, but it is harmful if inhaled and can cause brief tingling and reddening of the skin: avoid breathing the vapor or mist, and wash contaminated clothing before reuse.[2]
- When spraying overhead, wear eye protection (safety glasses, goggles or a face shield) and a dust/mist mask or respirator.[2]
2. Before you spray
- Remove or tightly cover fish tanks and disconnect aerators: it is extremely toxic to fish and aquatic invertebrates, and highly toxic to bees (don't let it reach plants bees are visiting).[2]
- In the home, cover food-preparation surfaces and utensils or wash them afterward, and cover or remove food; if spray reaches a food surface, wash it with soap and water.[2]
- Keep water-based sprays out of electrical boxes, conduits and motor housings. Outdoors, don't spray in rain or let it reach drains, gutters or water.[2]
3. Mixing
- Mix per gallon of water: 0.25 fl oz (7.5 mL) for 0.01%, a maintenance rate; 0.75 fl oz (22.7 mL) for 0.03%, for an initial clean-out; or 1.5 fl oz (45.4 mL) for 0.06%, for severe infestations.[2]
- Mix only what you need.[2]
4. Applying
- Indoors, use a coarse, low-pressure spray (50 psi or less) as spot or crack-and-crevice treatment: dark corners, floor drains, along and behind baseboards, behind sinks, stoves, refrigerators and cabinets, around plumbing, doors and windows, attics and crawl spaces. Never broadcast over floors or use it as a space spray.[2]
- For pantry pests, spray cupboards and shelves after removing the food and utensils.[2]
- Outdoors, treat the foundation up to 3 feet high and the soil, turf or ground cover next to it at about 1 gallon of spray per 1,000 sq ft without runoff; on sidewalks, driveways and patios, only spot or crack-and-crevice treatment, plus a 1-inch band around doors and windows.[2]
- Repeat at 21-day intervals, or as needed.[2]
5. After you spray
- Keep people and pets away until treated surfaces have dried.[2]
- Rinse equipment over the treated area so rinse water doesn't run into drains.[2]
First aid
- If inhaled, move the person to fresh air, call 911 if they aren't breathing, and call a poison control center or doctor; the label lists 1-800-334-7577 for emergency medical treatment information.[2]
Storage, spills and disposal
- Store it in its original container in a secure, dry place, away from temperature extremes and other pesticides and fertilizers.[2]
- Soak up spills with sawdust or another absorbent, sweep it up and dispose of it as chemical waste.[2]
From the safety data sheet
- The concentrate is a white liquid suspension with a characteristic odor; no flash point is listed, but dangerous gases can form if it burns.[6]
- Store it in the original container in a cool, dry place away from food, drink and animal feed, and protect it from freezing.[6]
- Soak up spills with an inert absorbent such as sand or sawdust, seal the waste in a labeled, closed container, and keep spills out of soil, waterways and drains.[6]
- Skin contact can cause temporary tingling and reddening of the skin, and the concentrate is harmful if inhaled.[6]
- Deltamethrin is extremely toxic to fish and water fleas; don't let rinse water reach surface or ground water, and don't spray or let it drift onto blooming plants that bees are visiting.[6]
Safety and environmental hazards
People
On skin it can cause tingling, itching, burning or numbness at the contact spot that usually fades within 48 hours; it is mildly irritating to eyes, and breathing enough of it can cause headache and dizziness. EPA classifies deltamethrin as not likely to be a human carcinogen.[1]
Pets
Dogs and cats can be affected if they eat, breathe or touch it: eating enough can cause vomiting, drooling, incoordination and tremors, and skin contact can prompt biting, scratching or licking. The Suspend SC label lets people and pets back into a treated area once it is dry.[1][2]
Bees and pollinators
Both labels warn of bee risk: Suspend SC is highly toxic to bees exposed to direct treatment, and the 2016 dust label says it is highly toxic to bees exposed to direct treatment on blooming crops or weeds; do not apply where bees are foraging.[2][5]
Fish and water
The Suspend SC label states it is extremely toxic to fresh water and estuarine fish and invertebrates and must not be allowed to run off into storm drains, gutters or surface water.[2]
Common questions
- Is deltamethrin safe around cats and dogs?
- Keep pets out until the treated area is dry, as the label directs. Pets that eat enough deltamethrin can vomit, drool, lose coordination or tremble, and skin contact can make them scratch or lick the spot.[2][1]
- Does deltamethrin cause cancer?
- EPA classifies deltamethrin as not likely to be a human carcinogen by any route of exposure, based on animal studies.[1]
- How long does deltamethrin last?
- Suspend SC sprays may be reapplied at 21-day intervals or as needed to keep control, according to its label; the dust label says it kills listed crawling insects for up to 8 months when left undisturbed.[2][5]
Sources
- National Pesticide Information Center, “Deltamethrin General Fact Sheet.” npic.orst.edu/factsheets/DeltaGen.html (accessed 2026-10-06)
- Bayer Environmental Science (posted by NYC Housing Authority), “Suspend SC Insecticide label, EPA Reg. No. 432-763 (85827804B 170421A V2, Sept. 5, 2019).” www.nyc.gov/assets/nycha/downloads/pdf/pest-control/products/suspend-sc-label.pdf (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “K-Othrine Dust Insecticide (formerly DeltaDust) label, EPA Reg. No. 432-772 (EPA-stamped, Aug. 5, 2016).” www3.epa.gov/pesticides/chem_search/ppls/000432-00772-20160805.pdf (accessed 2026-10-06)
- Insecticide Resistance Action Committee, “IRAC Mode of Action Classification Scheme, Version 11.5 (Feb. 2026).” irac-online.org/documents/moa-classification/ (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “K-Othrine Dust Insecticide (alternate brand name DeltaDust) label, EPA Reg. No. 432-772 (EPA-stamped, Aug. 5, 2016).” www3.epa.gov/pesticides/chem_search/ppls/000432-00772-20160805.pdf (accessed 2026-10-06)
- Bayer Environmental Science, “Suspend SC Insecticide Safety Data Sheet (Bayer Environmental Science, revised May 31, 2019; copy hosted by the City of Sioux Falls).” www.siouxfalls.gov/files/assets/public/v/1/health/public-health/mosquitos/suspend-sc-sds-5-31-19.pdf (accessed 2026-10-16)