By the HMNDP Editorial Team | Independent reporting on lawn care, landscaping, and the green-industry business.
Last reviewed: June 2026
What pyrethrin insecticide is
Pyrethrin insecticide is a natural botanical pesticide made from the dried flowers of Chrysanthemum cinerariifolium (also called Tanacetum cinerariifolium), a daisy grown mainly in Kenya, Tanzania, and Australia. The active compounds are six oily esters collectively called pyrethrins. They kill a wide range of insects on contact and break down within hours to a few days in sunlight.
Because pyrethrins come directly from a plant, several formulations qualify for organic use. That makes pyrethrin one of the few broad-spectrum insecticides organic growers can legally spray. The catch is that many products add a synthetic booster, which changes both the safety and the organic picture (covered below).
Pyrethrin vs pyrethrum vs pyrethroid
These three words are constantly confused, and the difference decides whether a product is organic. Pyrethrum is the raw flower extract. Pyrethrins are the six active chemicals inside that extract. Pyrethroids are synthetic, lab-made copies (like permethrin, bifenthrin, and cypermethrin) that are not plant-derived and are never organic.
| Term | What it is | Source | Organic-eligible? |
|---|---|---|---|
| Pyrethrum | Crude extract of the daisy flower | Natural (plant) | Yes, if unrefined |
| Pyrethrins | The 6 active insecticidal esters in that extract | Natural (plant) | Yes, often OMRI-listed |
| Pyrethroid | Synthetic copy (permethrin, bifenthrin, etc.) | Synthetic (lab) | No, never organic |
Simple rule for buyers: if the label ends in “-in” (pyrethrin) it is natural. If it ends in “-oid” (pyrethroid) or names permethrin, it is synthetic. For a synthetic comparison, see our guide to bifenthrin insecticide, a longer-lasting pyrethroid.
How pyrethrin works (mechanism of action)
Pyrethrin attacks an insect’s nervous system. It binds to voltage-gated sodium channels in nerve cells and holds them open, so the nerves fire uncontrollably. The insect goes into rapid paralysis, called “knockdown,” usually within minutes. Pyrethrin is classified as a Group 3A insecticide by the Insecticide Resistance Action Committee (IRAC).
Knockdown is fast but not always fatal. Some insects metabolize the dose and recover. That is why many products add piperonyl butoxide (PBO), a synergist that blocks the insect’s detoxifying enzymes so a smaller pyrethrin dose kills. PBO is synthetic, so any product containing it is not OMRI-listed for organic use.
What pests pyrethrin insecticide kills
Pyrethrin is broad-spectrum and controls most soft-bodied and flying insects on contact. It works on aphids, whiteflies, thrips, leafhoppers, mosquitoes, flies, gnats, fleas, ants, Japanese beetles, flea beetles, and many caterpillars. It gives fast knockdown but almost no residual, so it kills what it directly touches at spray time.
- Garden pests: aphids, whiteflies, thrips, spider mites (partial), leafhoppers
- Flying pests: mosquitoes, house flies, fruit flies, fungus gnats
- Household/pet pests: fleas, ants, roaches, bedbugs (limited)
- Beetles: Japanese beetles, flea beetles, cucumber beetles
Because there is little residual, repeat applications every 5 to 7 days are common for heavy infestations. For a wider view of options, see our best insecticide spray guide.
Is pyrethrin insecticide safe for humans, kids, and pets?
Pyrethrin has one of the lower mammalian toxicity profiles among insecticides, and the EPA classifies technical pyrethrins as low in acute oral toxicity. Humans and dogs break it down quickly. The real risks are cats, fish, and bees. Keep people and pets off treated surfaces until the spray is fully dry, per the label.
Cats: Cats metabolize pyrethrins slowly and are far more sensitive than dogs. Concentrated pyrethrin or pyrethroid flea products marketed for dogs can poison cats. Never apply a dog product to a cat, and keep cats away from freshly sprayed areas.
Fish and aquatic life: Pyrethrin is highly toxic to fish and aquatic invertebrates. Do not spray near ponds, aquariums, streams, or storm drains, and do not let runoff reach water.
Humans: Some people report skin, eye, or airway irritation. A small subset with ragweed or chrysanthemum allergies can react. Wear gloves, avoid inhaling the mist, and wash exposed skin.
Is pyrethrin safe around bees and pollinators?
No, pyrethrin is highly toxic to honeybees and other pollinators on direct contact. The saving grace is its short life: it degrades within hours in sunlight, so bees that arrive the next day face little residue. Timing is the whole game. Spray at dusk or after dark when bees are not foraging.
- Spray at dusk or early night, never in the heat of the day when bees forage.
- Keep spray off open blooms and flowering weeds where bees land.
- Mow or remove flowering weeds in the target area before spraying.
- Let residue dry and degrade overnight before bees return in the morning.
This dusk-timing rule is the single most useful safety habit for gardeners who want pest control without killing pollinators, and it is rarely spelled out on the front label.
Best pyrethrin insecticide brands and products compared
The pyrethrin insecticide market splits by concentration and by whether a product is OMRI-listed for organic use. Concentrates dilute cheaply for large areas; ready-to-use bottles suit spot spraying. The table below compares common US brands by active-ingredient percentage, organic status, and best use case. Prices are approximate 2026 retail bands.
| Product | Pyrethrin % | PBO / synergist | OMRI-listed | Form | Best for | Price band |
|---|---|---|---|---|---|---|
| PyGanic Gardening 1.4% | 1.4% | No | Yes | Concentrate | Certified-organic gardens | $30 to $45 |
| Monterey Pyganic (garden) | 1.4% | No | Yes | Concentrate | Organic vegetable beds | $28 to $40 |
| Southern Ag Natural Pyrethrin | 1.0% | No | Varies | Concentrate | Budget organic spraying | $18 to $28 |
| Bonide Pyrethrin Garden Spray | 0.02% RTU | Yes (PBO) | No | Ready-to-use | Fast spot knockdown | $12 to $18 |
| Garden Safe / Sevin-style RTU | ~0.02% | Yes (PBO) | No | Ready-to-use | Small non-organic gardens | $8 to $15 |
Key buying signal: if you need a genuinely organic spray, choose a product that is OMRI-listed and lists no PBO or piperonyl butoxide. Products with PBO knock down pests faster but forfeit organic certification. See our broader lawn care products guide for pairing choices.
Is pyrethrin OMRI-listed for organic gardening?
Some pyrethrin products are OMRI-listed and allowed under the USDA National Organic Program, but not all. OMRI (the Organic Materials Review Institute) reviews inputs for organic compliance. A pyrethrin product qualifies only if it uses natural pyrethrins with no synthetic synergist. Any product containing piperonyl butoxide (PBO) is disqualified from organic use.
Certified organic growers should confirm the exact product on the current OMRI Products List rather than trusting front-of-label “natural” claims. Requirements can vary by certifier and by state, so check with your certifying agent before spraying on a certified operation.
Application and where to buy
Always follow the product label, which is the legally binding instruction. In general: dilute concentrates per the label rate, spray to lightly coat leaf tops and undersides where pests hide, and reapply every 5 to 7 days for heavy infestations. Spray at dusk, avoid open blooms, and never apply near water.
- Read the label and mix the concentrate to the listed rate for your pest.
- Test-spray one plant and wait 24 hours to check for leaf burn.
- Spray at dusk, coating both sides of leaves until just wet.
- Keep pets and children off until fully dry; repeat weekly as needed.
You can buy pyrethrin insecticide on Amazon, at farm and ranch stores (Tractor Supply, Rural King), garden centers, and agricultural suppliers such as DoMyOwn, Arbico Organics, and Gempler’s. Organic-certified concentrates like PyGanic are widely stocked online. Compare concentration and OMRI status before price, since a cheap RTU may contain PBO you do not want.
Frequently Asked Questions
What is pyrethrin insecticide and how does it work?
Pyrethrin insecticide is a natural pesticide made from dried Chrysanthemum cinerariifolium flowers. It kills insects on contact by binding to sodium channels in their nerve cells and holding them open, causing rapid paralysis known as knockdown. It is broad-spectrum, works within minutes, and breaks down in sunlight within hours to a few days, leaving little residue.
What is the difference between pyrethrin, pyrethrum, and pyrethroid?
Pyrethrum is the raw extract of the chrysanthemum flower. Pyrethrins are the six active insecticidal compounds inside that extract, both natural and often organic-eligible. Pyrethroids (permethrin, bifenthrin, cypermethrin) are synthetic lab-made copies that last longer but are never organic. Quick rule: “-in” endings are natural, while “-oid” endings and permethrin are synthetic.
Is pyrethrin insecticide safe for humans, kids, and pets?
Pyrethrin has low acute toxicity to humans and dogs, which break it down quickly, and the EPA rates technical pyrethrins as low in oral toxicity. The main risks are cats, which metabolize it slowly, and fish, which it is highly toxic to. Keep people and pets off treated areas until fully dry and never use dog flea products on cats.
Is pyrethrin safe to use around bees and pollinators?
No, pyrethrin is highly toxic to honeybees on direct contact, but it degrades within hours in sunlight. To protect pollinators, spray at dusk or after dark when bees are not foraging, keep spray off open blooms and flowering weeds, and let residue break down overnight before bees return in the morning.
What pests does pyrethrin insecticide kill?
Pyrethrin controls most soft-bodied and flying insects on contact, including aphids, whiteflies, thrips, leafhoppers, mosquitoes, flies, gnats, fleas, ants, Japanese beetles, flea beetles, and many caterpillars. It gives fast knockdown but little residual protection, so it mainly kills insects present at spray time. Heavy infestations usually need reapplication every 5 to 7 days.
What are the best pyrethrin insecticide brand names and products?
Common US brands include PyGanic Gardening (1.4%, OMRI-listed), Monterey Pyganic, Southern Ag Natural Pyrethrin, Bonide Pyrethrin Garden Spray, and various ready-to-use bottles. Organic growers should choose OMRI-listed concentrates like PyGanic with no PBO. Ready-to-use products often contain piperonyl butoxide for faster knockdown but are not organic-approved. Match concentration and OMRI status to your use case.
Where can I buy pyrethrin insecticide?
You can buy pyrethrin insecticide on Amazon, at farm and ranch stores like Tractor Supply and Rural King, at local garden centers, and from agricultural suppliers such as DoMyOwn, Arbico Organics, and Gempler’s. Organic concentrates like PyGanic are widely stocked online. Compare active-ingredient percentage and OMRI status before comparing price.
Is pyrethrin insecticide OMRI-listed or approved for organic gardening?
Some pyrethrin products are OMRI-listed and allowed under the USDA National Organic Program, but not all. A product qualifies only if it uses natural pyrethrins with no synthetic synergist. Any product containing piperonyl butoxide (PBO) is disqualified from organic use. Certified growers should confirm the exact product on the current OMRI Products List and check with their certifier.