How do I mix and apply Suspend SC correctly?

Shake the concentrate well before measuring, since the active settles in the container over time, then measure to the exact label rate — never eyeball it. Mix in water and agitate or invert the sprayer to keep it suspended, re-agitating if you pause during the job. Apply as an even, continuous band to targeted surfaces, harborage, cracks, and entry points rather than broadcasting over driveways or patios, which the label prohibits for impervious horizontal surfaces.

Does Suspend SC actually work?

Yes — deltamethrin is one of the most potent pyrethroids available, and the suspension-concentrate formulation gives it a genuinely durable, non-staining residual when mixed and applied correctly. As an even band across a broad structural pest list, it's a real professional-grade workhorse. What it doesn't do is deliver instant knockdown or reach a colony or nest behind the insects you're treating, so judge results over days and weeks of sustained suppression, not minutes after application.

Why do I still see bugs after applying it?

A residual band kills insects that contact the treated surface over hours to a couple of days, so early activity doesn't mean failure. If activity persists well past that window despite accurate mixing and even application, the likely cause is either an untreated interior source, a colony or nest the surface band structurally can't reach, or — for cockroaches — documented pyrethroid resistance. That's a signal to add baiting or dusting, or call a licensed technician, rather than reapplying more of the same product.

Why does shaking and agitation matter so much?

Because a suspension concentrate is exactly what it sounds like — the active ingredient is suspended in liquid and settles over time if left alone. An unshaken bottle or an unagitated tank delivers progressively weaker, uneven coverage as you work through a job, which is the single biggest reason this professional product underperforms in inexperienced hands. Shake before measuring and re-agitate throughout application to get the durable, even residual the product is actually capable of.

Can I use it on my driveway or patio?

Not as a broadcast application — the label specifically prohibits broadcasting Suspend SC over impervious horizontal surfaces like sidewalks, driveways, and patios, largely due to runoff concerns since deltamethrin is extremely toxic to fish and aquatic invertebrates. You can use it for labeled spot and crack-and-crevice treatment and perimeter banding around structures, but treat open paved surfaces as off-limits for a full broadcast application.

Is it safe to use around my pets?

The main precaution is keeping pets and kids off any treated surface until it's completely dry, since that's when exposure risk is highest. Deltamethrin is also extremely toxic to fish and aquatic invertebrates and highly toxic to bees, so keep it away from water, drains, and blooming plants during application. For the full per-species pet-safety verdict on this specific product, see our companion review at /is-pest-control-safe-for-pets/suspend-sc-insecticide-concentrate-by-bayer.

Daniel Brady · NH-Licensed Pesticide Applicator · License #782664

How to Use Suspend SC Insecticide Concentrate by Bayer

Workhorse

Deltamethrin 4.75% (0.42 lb per gallon)

Mixed and applied correctly, Suspend SC is a genuine pro-grade workhorse. It's a deltamethrin 4.75% suspension concentrate — shake it well before measuring, dilute to the exact label rate, and keep the tank agitated so the active stays suspended throughout the job. Applied as an even, continuous band to targeted surfaces, harborage, cracks, and entry points, it delivers durable residual control across a broad structural pest list with a non-staining finish. What it does not do is deliver instant knockdown or reach a colony or nest — it kills what contacts the treated surface, not what's living behind it — and documented pyrethroid resistance in some German cockroach populations can blunt its effectiveness against an established roach infestation.

At a glance

Efficacy: Workhorse
Best job: Laying durable, even residual bands indoors and around structures when mixed accurately
Format: Professional dilutable suspension concentrate (SC) — mix-your-own, shake well and keep agitated; also marketed as K-Othrine SC; for indoor and outdoor residual control on a broad structural pest list
Technique: Moderate technique

The honest verdict

Does this product actually work?

The verdict on this product

WorkhorseModerate technique

Workhorse

A pro-grade workhorse for durable, even residual bands — mixed right, not a colony cure.

Deltamethrin is one of the most potent pyrethroids available, and Suspend SC's suspension-concentrate formulation gives it long residual life with a genuinely non-staining, water-based finish — a real professional-grade advantage over many retail sprays. But it kills foragers and exposed insects on contact, not colonies, and the same resistance and interior-source limits that apply across this whole product category apply here too. Mixed accurately and applied as an even band, it's a real workhorse; guessed at or left unagitated in the tank, it underperforms.

Best for

Durable, even residual bands indoors and around structures on a broad pest list, when measured and mixed to the exact label rate.

Skip it for

Instant knockdown expectations, nests that need dusting or baiting instead of a surface band, and resistant German cockroaches.

Read the label first

What it is — and what it's really for

The label is the law. Here's the honest read on the format, the one job it does well, and the job people wrongly buy it for.

Format

Professional dilutable suspension concentrate (SC) — mix-your-own, shake well and keep agitated; also marketed as K-Othrine SC; for indoor and outdoor residual control on a broad structural pest list

Indoor / outdoor

both

Residual

Long residual with a non-staining, water-based finish; outdoor use is limited to perimeter, spot, and crack-and-crevice treatments — broadcast over impervious horizontal surfaces is prohibited by label

Target pests

Ants, Spiders, Cockroaches, Fleas, Ticks, Mosquitoes, Scorpions, and more per label

Best job

Laying durable, even residual bands indoors and around structures when mixed accurately

Active ingredient

Deltamethrin (4.75% (0.42 lb per gallon))

Not for (honest)

Instant knockdown expectations, a nest you should dust or bait instead, or resistant German cockroaches

The technician's method

The technique walkthrough

Where DIY succeeds or fails is in the placement, patience, and the small pro moves the label never mentions. Follow the label; these are the technique details on top of it.

Moderate technique~45-90 min for an average house; contact kill over hours to a couple of days, residual holds for weeksTools:Pump or backpack sprayer, Measuring device, Gloves, Eye protection

This is a moderate-difficulty product because the whole professional-grade advantage lives in shaking, measuring, and agitating correctly — skip any of those and it performs like a cheaper spray.

Shake before measuring
Shake the concentrate well before measuring — the active must be fully suspended, not settled at the bottom of the container.
Common mistake
Measuring straight from an unshaken bottle — the first measured dose comes out weaker than the label rate.
Measure precisely
Measure to the exact label rate. Too weak leaves no real barrier; too strong wastes product, risks runoff, and violates the label.
Mix and agitate
Mix in water and agitate or invert the sprayer to keep the concentrate suspended; re-agitate if you pause.
Pro move
Invert or agitate the sprayer periodically through the job so the last gallon deposits as strongly as the first.
Apply an even, continuous band
Apply to targeted surfaces, harborage, cracks, and the exterior perimeter/entry points as an even, continuous band — not a broadcast over driveways or patios.
Caution
Broadcast application over impervious horizontal surfaces like sidewalks and driveways is prohibited by label.
Reapply on schedule
Reapply per label, and refresh exterior bands sooner as weather degrades them.
Caution
Keep it out of storm drains and water — extremely toxic to fish — and away from blooming plants, as deltamethrin is also highly toxic to bees.

Habits that decide it

Do & don't

Shake before measuring and agitate the tank throughout
Measure to the exact label rate
Band entry points and harborage evenly
Respect outdoor spot/crack-and-crevice restrictions

Don't

Don't broadcast over sidewalks, driveways, or patios
Don't over-concentrate the mix
Don't let it reach water or drains
Don't expect it to eliminate a colony
Don't skip re-agitating mid-job

The honesty moat

Where it works vs. where it fails

No product fixes everything. This is the honest boundary — the situations it genuinely handles, and the ones it simply won't.

Where it works

Laying even, durable residual bands indoors and around structures
Mixed and agitated accurately to the label rate
Treating a broad structural pest list — ants, spiders, roaches, fleas, ticks, mosquitoes
Non-staining application on surfaces where appearance matters

Where it fails

You need instant, same-day knockdown
There's a colony or nest the surface band can't reach
German cockroaches carry documented pyrethroid resistance
The concentrate wasn't shaken or the tank wasn't kept agitated, leaving uneven coverage

Don't throw money away

Mistakes that waste the product

Not shaking or re-agitating

The active settles in the container and tank, so unshaken or unagitated application delivers uneven, progressively weaker coverage.

Fix

Shake before measuring and re-agitate the sprayer throughout the job, especially after any pause.

Wrong dilution

Too weak leaves no real barrier; too strong wastes product, risks runoff, and can violate the label.

Fix

Measure to the exact label rate every time.

Broadcasting over horizontal surfaces

That's off-label for this product and increases runoff risk toward drains and water.

Fix

Confine application to bands, spots, and crack-and-crevice treatment per label.

Ignoring the interior source

A residual band reduces exposed-insect activity but doesn't touch a colony or nest already established indoors.

Fix

Find and treat the actual source, or pair with baiting for colony pests.

Expecting instant knockdown

Insects die from contact over hours to a couple of days, not seconds — judging it too soon leads to unnecessary reapplication.

Fix

Give the residual time to work and judge results over days, not minutes.

Calibrated expectations

What to expect — and when

This is a residual tool with a delayed kill and a genuinely durable hold — judge it on sustained suppression, not instant results.

Hours to 1-2 days
Insects contacting the treated residue die — not instantly, but reliably.
Days 3-14
New activity on treated surfaces drops noticeably as the residual band takes effect.
Weeks (surface- and weather-dependent)
Residual control continues, with outdoor bands fading faster under UV and rain than indoor, non-porous applications.

When results plateau

Even a well-mixed deltamethrin band levels off when the real driver is an interior harborage, an outdoor colony the perimeter never reaches, or pyrethroid-resistant German roaches — the residual trims exposed traffic but leaves an established interior population intact.

Know the ceiling

When to stop DIY & call a pro

Suspend SC is genuinely professional-grade, and its accuracy requirements are exactly where DIY often falls short. These are the signals to bring in a licensed technician:

You're unsure of the correct dilution, agitation routine, or use site
Mixing and coverage errors waste a professional concentrate's entire advantage, and getting it right takes training and practice.
Cockroaches persist despite correctly mixed, evenly applied treatment
Documented pyrethroid-resistant German cockroach populations can survive residual treatment alone and need baiting or dusting alongside it.
You find carpenter ants, frass, or a suspected nest in structural wood
A surface residual band doesn't reach an in-wall colony — that needs inspection and often void treatment.
You need broader structural pest coverage than a single residual application provides
A licensed technician can combine Suspend SC with baiting, dusting, and IGRs into a coordinated program a single product can't replicate.

Anchor's NH-licensed technicians mix and apply pro-grade concentrates like Suspend SC at the correct rate, with the agitation and coverage accuracy that make the difference, and pair it with baiting or dusting where a residual band alone won't finish the job. Free inspection, same-day service across southern and central New Hampshire.

Mixing and agitation accuracy is the whole game

Get a Free inspection (603) 785-0118

Before you treat

Is it safe for pets & kids?

The short version lives here; the full per-species verdict lives on this product's pet-safety page.

Deltamethrin is a pyrethroid, extremely toxic to fish and aquatic invertebrates, and highly toxic to bees, so keep it well away from water, drains, and blooming plants during mixing and application. Around pets and kids, the practical precaution is staying off the treated area until it's fully dry.

Re-entry: Keep children and pets off treated surfaces until the application is fully dry.

If there's an exposure, call

ASPCA Animal Poison Control: (888) 426-4435 Pet Poison Helpline: (855) 764-7661 Northern New England Poison Center: (1-800) 222-1222

See the full per-species pet-safety verdict for this product

New Hampshire context

Pro-grade residual across NH's seasons

A durable, non-staining residual band matters most across southern and central New Hampshire's warm-season pest pressure and fall ingress, when ants, spiders, and occasional invaders push toward structures repeatedly. Because Suspend SC's advantage depends on mixing and agitation accuracy most homeowners don't practice regularly, Anchor Pest Services applies it at the correct rate and site across Manchester, Nashua, Concord, and the surrounding towns rather than leaving that precision to a one-time DIY job.

Service area

Southern New Hampshire

Anchor Pest Services · NH license #782664 · NEPMA member · family-owned since 2017.

Common questions

Frequently asked

Sources & further reading(3)

[1]
EPA/Bayer K-Othrine (Suspend SC) label, Reg. No. 432-763
Verified active (deltamethrin 4.75%), suspension-concentrate format, outdoor spot/crack-and-crevice restrictions, prohibited broadcast on impervious surfaces
epa_labelverified 2026-07-14
[2]
Bayer Environmental Science — Suspend SC SDS
Formulation facts, non-staining water-based finish, use-site list — facts only
manufacturerverified 2026-07-14
[3]
NPIC — Deltamethrin General Fact Sheet
Deltamethrin class, aquatic and bee toxicity
npicverified 2026-07-14

Written & reviewed by

Verified

Daniel Brady

NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)

Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.

Verify license

Last updated July 2026

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Professional Pest Control

Pro-Grade Products Deserve Pro-Grade Application

Suspend SC rewards precision and punishes guesswork. Anchor Pest Services mixes, agitates, and applies it at the correct rate and site across southern and central New Hampshire. Family-owned since 2017, NH license #782664.

Get a Free inspection (603) 785-0118

Accurate, licensed mixing and application
NH-licensed applicators (#782664)
Free inspection — same-day service across southern NH

NH License #782664 · No obligation · We answer in person

Keep Exploring

How to Use Suspend SC Insecticide Concentrate by Bayer

Does this product actually work?

What it is — and what it's really for

The technique walkthrough

Shake before measuring

Measure precisely

Mix and agitate

Apply an even, continuous band

Reapply on schedule