What is spinosad insecticide?
Spinosad insecticide is a natural insect killer made by fermenting Saccharopolyspora spinosa, a soil bacterium first isolated in 1985 from an abandoned rum distillery in the Virgin Islands. The active ingredient is a blend of two compounds, spinosyn A and spinosyn D. It controls thrips, caterpillars, leafminers, and fire ants, is OMRI-listed for organic growing, and has low toxicity to people and pets.
By the HMNDP Editorial Team (independent lawn-care and landscaping reporting). Last reviewed: June 2026.
Spinosad sits in Group 5 of the Insecticide Resistance Action Committee (IRAC) classification, a mode of action shared only with its semi-synthetic cousin spinetoram. That single-group status is why rotation matters, a point we cover below. For a broader comparison of chemistries, see our roundup of the best insecticide spray options for home gardens.
How spinosad works (mode of action)
Spinosad attacks the insect nervous system. It binds to nicotinic acetylcholine receptors at a site no other insecticide uses, and also acts on GABA receptors. The result is continuous, involuntary muscle firing that leads to paralysis and death within 1 to 3 days. It works both by ingestion and by contact, but ingestion is several times more lethal, so thorough leaf coverage matters.
Because the binding site is unique, spinosad shows no cross-resistance with older classes like organophosphates, carbamates, or pyrethroids. That makes it a useful rotation partner against pests that already resist those chemistries.
What pests spinosad kills (and what it does not)
Spinosad is strong on chewing and rasping insects and weak on sap-suckers and mites. It controls thrips, caterpillars and worms (hornworms, armyworms, loopers, fruitworms), leafminers, fire ants, spotted wing drosophila, and some beetles. It gives little to no control of aphids, whiteflies, or spider mites, and can even flare spider mite numbers by killing their predators.
| Pest group | Spinosad control |
|---|---|
| Thrips (western flower, chilli) | Strong |
| Caterpillars and worms | Strong |
| Leafminers | Strong |
| Fire ants | Strong (baits and drenches) |
| Fruit flies / spotted wing drosophila | Good |
| Colorado potato beetle, some beetles | Moderate |
| Aphids and whiteflies | Poor to none |
| Spider mites | None (can worsen) |
If aphids are your problem, spinosad is the wrong tool. Reach instead for the targeted options in our guide to choosing an aphid insecticide. For bagworms, which are caterpillars inside silk cases, spinosad can work but timing on young larvae is everything, as our bagworm insecticide guide explains.
Is spinosad OMRI-listed for organic gardening?
Yes, certain spinosad products are OMRI-listed and approved for certified organic production. The professional-grade Entrust SC and Entrust WP carry OMRI listing, as do several home formulations such as Captain Jack’s Deadbug Brew. Not every spinosad label qualifies, so organic growers should confirm the OMRI seal on the specific container rather than assuming all spinosad is allowed.
The distinction matters because spinetoram, the related molecule, is semi-synthetic and is not approved for organic use.
How to mix and apply spinosad on vegetables, fruit, and citrus
Spinosad is labeled for a wide range of food crops including tomatoes, peppers, leafy greens, brassicas, tree fruit, berries, and citrus. Home concentrates typically call for 1 to 4 tablespoons per gallon of water depending on pest pressure. The restricted-entry interval (REI) is short and the pre-harvest interval (PHI) is often just 1 day, but both vary by crop and product.
| Product | Typical mix rate | REI | PHI |
|---|---|---|---|
| Captain Jack’s Deadbug Brew (concentrate) | 2 to 4 tbsp per gallon | Until dry | 1 day (most crops) |
| Monterey Garden Insect Spray | 1 to 4 tbsp per gallon | Until dry | 1 day (most crops) |
| Entrust SC (professional, OMRI) | Per label, by crop | 4 hours | 1 to 28 days by crop |
These figures are general references. The label on your container is the legal authority and always wins if it differs. Spray to wet the foliage without heavy runoff, and reapply after rain since spinosad is not strongly rainfast until it dries.
Spinosad safety for humans and pets
Spinosad has low mammalian toxicity. The acute oral LD50 in rats exceeds 5,000 mg/kg, placing it in the EPA’s lowest concern categories, and the agency classified it as a reduced-risk insecticide. It is not readily absorbed through skin and breaks down in the environment. Pets and children can return to treated areas once the spray has dried.
As with any pesticide, keep people and animals off wet foliage, store containers sealed, and wash harvested produce.
Is spinosad safe for bees? The dusk-and-dry protocol
Spinosad is highly toxic to honey bees while the spray is wet, then becomes practically non-toxic once residues dry, usually within about 3 hours. That single fact drives the whole bee-safety approach: the danger window is short and avoidable. Spray in the evening after foragers have quit for the day, let it dry overnight, and keep it off open flowers.
- Spray at dusk or after sunset, when bees have stopped foraging.
- Allow at least 3 hours of drying, ideally overnight, before bloom opens.
- Do not treat plants in open bloom, and avoid drift onto flowering weeds nearby.
- Mow or remove flowering weeds under the canopy before treating.
Most product pages note that spinosad is toxic to bees but stop there. The actionable rule is timing, not avoidance: applied dry-side of the window, spinosad is one of the more bee-considerate options in an organic program.
Resistance management: rotate and cap applications
Spinosad resistance is real and documented. Western flower thrips and diamondback moth (a brassica pest) have developed field resistance in multiple regions, and spotted wing drosophila resistance has been reported. Because spinosad and spinetoram are the only members of IRAC Group 5, over-reliance on spinosad burns both tools at once.
Protect the chemistry with two habits:
- Rotate modes of action. Alternate spinosad with a different IRAC group (for example Bt for caterpillars, or a Group 3 pyrethrin) rather than spraying it back to back.
- Cap applications. Many labels limit spinosad to a set number of sprays per crop per season and no more than a few consecutive applications. Follow that ceiling even when the pest is still present.
This is the warning almost no consumer article gives, yet it is the difference between a tool that keeps working and one that quietly fails on your worst pest.
Spinosad vs spinetoram, neem, pyrethrin, and Bt
Spinosad is the organic-approved spinosyn; spinetoram is a stronger, semi-synthetic version of the same chemistry that is not organic-approved. Against other natural options, spinosad beats neem, pyrethrin, and Bt on thrips and leafminers, ties Bt on caterpillars, and loses to neem and pyrethrin on aphids and other soft-bodied suckers. No single product covers every pest.
| Product | Class / IRAC | Best on | Weak on | Organic |
|---|---|---|---|---|
| Spinosad | Spinosyn / Group 5 | Thrips, caterpillars, leafminers | Aphids, mites | Yes (OMRI products) |
| Spinetoram | Spinosyn / Group 5 | Same, more potent | Aphids, mites | No |
| Neem (azadirachtin) | Botanical IGR | Soft-bodied pests, mite suppression | Fast knockdown | Yes |
| Pyrethrin | Botanical / Group 3 | Fast broad knockdown | Residual, bee safety | Yes |
| Bt kurstaki | Microbial / Group 11 | Caterpillars only | Everything non-caterpillar | Yes |
A practical read: use Bt if the only pest is caterpillars, spinosad if thrips or leafminers are in the mix, and neem or pyrethrin when aphids and whiteflies dominate. Synthetic pyrethroids such as bifenthrin hit a broader range but are not organic and are harder on beneficials and bees.
How long spinosad takes to work and how long it lasts
Spinosad acts fast on feeding: treated insects usually stop eating within hours and die within 1 to 3 days. Residual protection on the plant runs roughly 7 to 10 days, though sunlight degrades it and its foliar half-life can be as short as 1 to a few days. Reapply on a 7 to 10 day interval during active pest pressure, within the label’s seasonal cap.
Common spinosad brand names and products
Spinosad is sold under several familiar names. For home gardeners the main choices are Captain Jack’s Deadbug Brew (Bonide) and Monterey Garden Insect Spray. Professionals and organic market growers use Entrust (OMRI-listed) and Conserve SC for turf and ornamentals, while GF-120 is a fruit-fly bait.
- Captain Jack’s Deadbug Brew (Bonide) — home concentrate, dust, and ready-to-use.
- Monterey Garden Insect Spray — home concentrate.
- Entrust SC / Entrust WP (Corteva) — OMRI-listed, professional and certified-organic use.
- Conserve SC — turf and ornamental market.
- GF-120 NF Naturalyte — spinosad fruit-fly bait.
Frequently Asked Questions
What is spinosad and how does it work as an insecticide?
Spinosad is a natural insecticide fermented from the soil bacterium Saccharopolyspora spinosa, combining spinosyn A and spinosyn D. It kills insects by binding to nicotinic acetylcholine and GABA receptors in the nervous system, triggering uncontrolled muscle activity, paralysis, and death within 1 to 3 days. It works by both ingestion and contact, with ingestion far more lethal, so full leaf coverage improves results.
What insects and pests does spinosad kill?
Spinosad controls chewing and rasping pests: thrips, caterpillars and worms (hornworms, armyworms, loopers, fruitworms), leafminers, fire ants, spotted wing drosophila, and some beetles like Colorado potato beetle. It is weak or useless against sap-sucking insects such as aphids and whiteflies, and it does not control spider mites. In fact, it can flare mite populations by killing their natural predators.
Is spinosad safe for bees, pets, and humans?
Spinosad has low toxicity to humans and pets, with a rat oral LD50 above 5,000 mg/kg and an EPA reduced-risk rating; people and animals can return once sprays dry. Bees are the exception: spinosad is highly toxic while wet but practically non-toxic after drying, roughly 3 hours. Spray at dusk, let it dry overnight, and avoid open bloom to protect pollinators.
Is spinosad approved for organic gardening (OMRI listed)?
Yes, specific spinosad products are OMRI-listed and allowed in certified organic production, including Entrust SC, Entrust WP, and home formulations such as Captain Jack’s Deadbug Brew. Not every spinosad label qualifies, so confirm the OMRI seal on the exact container you buy. Spinetoram, the closely related molecule, is semi-synthetic and is not approved for organic use.
What are the common spinosad brand names and products?
For home gardeners the leading spinosad products are Captain Jack’s Deadbug Brew (Bonide) and Monterey Garden Insect Spray. Professional and organic growers use Entrust, which is OMRI-listed, and Conserve SC for turf and ornamentals. GF-120 NF Naturalyte is a spinosad-based fruit-fly bait. All share the same active ingredient at different concentrations and formulations.
How do you mix and apply spinosad, and what is the pre-harvest interval?
Home spinosad concentrates typically mix at 1 to 4 tablespoons per gallon depending on pest pressure. Spray to wet the foliage without heavy runoff. The restricted-entry interval is short (until dry, or 4 hours for Entrust), and the pre-harvest interval is often just 1 day on many vegetables, though it can range up to 28 days by crop and product. Always follow the container label.
Spinosad vs neem oil vs pyrethrin, which is better for garden pests?
It depends on the pest. Spinosad wins on thrips, caterpillars, and leafminers. Neem oil suits soft-bodied pests like aphids and whiteflies and suppresses mites, but acts slowly. Pyrethrin gives fast broad knockdown but has short residual and is hard on bees. For caterpillar-only problems, Bt is the most selective. Match the product to the pest rather than seeking one cure-all.
How long does spinosad take to work and how long does it last?
Spinosad acts quickly on feeding insects, which stop eating within hours and die within 1 to 3 days. Residual control on the plant lasts roughly 7 to 10 days, though sunlight breaks it down and its foliar half-life can be as short as 1 to a few days. Reapply every 7 to 10 days during active infestations, staying within the label’s seasonal application limit.