Spinosad: what it kills and what it harms
Spinosad is a nerve poison made by a soil bacterium, sold for home gardens as Captain Jack's Deadbug Brew and Monterey Garden Insect Spray. It kills caterpillars, thrips, leafminers and Colorado potato beetle, and it is approved for organic gardening. It is not harmless to beneficials. The label says it is toxic to bees for 3 hours after spraying, and NPIC says dried spray has little or no effect on them. Parasitic wasps such as Aphidius and Encarsia are killed by it, and fresh residues also harm predatory mites and lacewing larvae for up to a week.
Also sold or listed as: spinosyn, Captain Jack's Deadbug Brew, Monterey Garden Insect Spray, Entrust, Conserve.
At a glance
- Active
- Spinosad (spinosyns A and D, made by the soil bacterium Saccharopolyspora spinosa)
- Residue
- Short to intermediate: UC IPM gives hours to days (tomato table) or days to 2 weeks (greenhouse and nursery table); Encarsia harmed up to 28 days
- Lethal
- 2 of 6 beneficials
- Caution
- 4 of 6 beneficials
What it works on
- CaterpillarsThe main label use. Cabbageworms, loopers, diamondback moth and armyworms on cole crops, plus "worms (caterpillars)" on tomatoes, peppers, leafy greens and fruit trees.
- Western flower thripsOn the label for most vegetables, fruit and ornamentals. On bulb vegetables such as onion, the label claims only suppression.
- Colorado potato beetleOn the label for fruiting vegetables and potatoes, up to 6 sprays a year. The label caps sprays per crop to slow resistance, so rotate it with other products.
- LeafminersListed on most vegetable crops. The front panel also claims control of citrus leafminer.
- Codling mothOn apples and pears: up to 6 sprays a year, 10 days apart, and 7 days before picking.
- Fire antsDiluted spray poured on the mound as a drench, 1–2 gallons per mound, best between 65 and 85 °F.
- Spider mites on ornamentalsOn the ornamental section of the label only. Spray before webbing appears, and repeat every 7–10 days.
Effect on beneficials
- Aphidius colemaniIn residue bioassays, Aphidius colemani adults were about 20 times more susceptible to spinosad than to imidacloprid or lambda-cyhalothrin, and residues above 200 ng/cm² halved adult lifespan. UC IPM's greenhouse and nursery table rates spinosad high (H → lethal) for parasites. UC IPM's tomato table is milder (low to moderate for parasites). In a UK leaf-residue study spinosad was among the least persistent products tested on A. colemani, with little or no activity detectable after 14 days in its wax-stripping experiment. — D'Ávila et al. 2018, J. Econ. Entomol.; UC IPM floriculture table (2022); Anjum & Wright 2023Lethal — high, over 75 %
- Encarsia formosaHighly toxic to Encarsia formosa in lab bioassays on greenhouse cucumber, and still highly toxic to adults put on leaves sprayed up to 28 days earlier. UC IPM rates spinosad high (H → lethal) for parasites in greenhouse and nursery crops. — Jones et al. 2005, Pest Manag. Sci. 61:179; UC IPM floriculture table (2022)Lethal — high, over 75 %
- Amblyseius cucumerisEvidence is mixed. A direct spray killed more than 90% of N. cucumeris, but residues older than about 3–4 days fell below the 25% mortality threshold, and the authors say predatory mites can be released 6 days after a spray. A Canadian study on greenhouse cucumber found low toxicity to A. cucumeris in lab bioassays and on 1-day-old residues. A UK study found residue exposure to spinosad the most harmful treatment it tested on four thrips-eating mites. UC IPM rates predatory mites medium (M → caution). — Rahman et al. 2011, Pest Manag. Sci. 67:993; Jones et al. 2005; Cuthbertson et al. 2012, Pest Manag. Sci. 68:1289; UC IPM floriculture tableCaution — moderate, 25–75 %
- Phytoseiulus persimilisUC IPM rates predatory mites medium (M → caution) in greenhouse and nursery crops, though that rating is mostly from the western predatory mite. In a Kansas State greenhouse trial on ivy geranium, a thrips-rate spray of Conserve applied the day before or after release did not reduce how well P. persimilis controlled spider mites. No lab mortality figure for this species was found. — UC IPM floriculture table (2022); Holt et al. 2006, Exp. Appl. Acarol. 38:141Caution — moderate, 25–75 %
- Chrysoperla carneaUC IPM rates spinosad medium (M → caution) for general predators in its greenhouse and tomato tables, and notes it is toxic to lacewing larvae when sprayed and for 5–7 days afterwards. A 2012 review of spinosyn side effects found lethal or sublethal effects in almost every group of beneficial arthropods tested. — UC IPM floriculture, tomato and cucurbit tables; Biondi et al. 2012, Pest Manag. Sci. 68:1523Caution — moderate, 25–75 %
- Orius insidiosusModerately toxic to Orius insidiosus in lab bioassays and on greenhouse cucumber leaves sprayed 1 and 8 days earlier (moderate → caution). — Jones et al. 2005, Pest Manag. Sci. 61:179Caution — moderate, 25–75 %
No data never means safe: treat an unrated pairing as caution and try it on a small area first. See every product side by side →
How it works
Spinosad is a mix of two natural compounds, spinosyns A and D, made by a soil bacterium. It attacks the insect nervous system. Insects that eat it or touch it twitch uncontrollably, become paralysed and usually die within 1–2 days (NPIC). The Captain Jack's label warns that pests may stay on the plant for several hours, but they will have stopped feeding.
It is in IRAC group 5, a class of its own, which makes it useful in rotation. Both labels cap the number of sprays per crop each year, and the Bonide label says this is to help avoid resistance.
Sunlight breaks it down. On leaves its half-life is 2–16 days, and in sunlit water less than a day (NPIC). It is not systemic, although leaves absorb a little.
Its selectivity is often overstated. The home labels say it "does not significantly impact predatory beneficial insects, predatory mites and spiders", but UC IPM and the published trials say otherwise. It kills parasitic wasps, and UC IPM says it is toxic to lacewing and syrphid larvae, predatory beetles and predatory thrips when sprayed and for 5–7 days afterwards. Residues also harmed predatory mites for 3–6 days in lab tests (Rahman et al. 2011). The risk to bees is mostly while the spray is wet.
Using it
- Products
- Captain Jack's Deadbug Brew Concentrate (Bonide, EPA Reg. 4-471) and Monterey Garden Insect Spray (EPA Reg. 62719-314-54705). Both are 0.5% spinosad. The Bonide label and the base label Monterey's is registered under (62719-314) are both marked for organic gardening.
- Rate
- 2 fl oz (4 Tbsp) per gallon of water, which is 1 Tbsp per quart. In vegetable gardens, use no more than 3 gallons of spray per 1,000 sq ft. Wet both sides of the leaves.
- Interval and limits
- These vary by crop. On tomatoes, peppers and eggplant: up to 6 sprays a year, at least 4 days apart. On cole crops and leafy greens: 6 a year, 4 days apart. On apples: 6 a year, 10 days apart.
- Days to harvest
- 1 day for most vegetables (fruiting, cole, leafy and bulb crops), strawberries and caneberries. 3 days for blueberries and other bushberries, most cucurbits (cucumber 1) and root vegetables. 7 days for apples, pears, grapes and potatoes. Check the crop table on the label.
- Re-entry
- The home labels give no re-entry interval and no signal word.
- Timing
- Spray in the evening, after bees have stopped foraging, so the spray is dry by the time they return. UC IPM allows sprays on flowering plants only between sunset and midnight.
Cautions
- Bees
- The label says: "This product is toxic to bees exposed to treatment for 3 hours following treatment. Do not apply this pesticide to blooming, pollen-shedding or nectar-producing parts of plants if bees may forage on the plants during this time period." NPIC calls it very highly toxic to bees, with little or no effect once the spray has dried. UC IPM gives it bee precaution II: keep it off flowering plants unless the spray goes on between sunset and midnight.
- Released beneficials
- Do not use it where Aphidius or Encarsia are working: residues killed Encarsia for up to 28 days. Released predatory mites can go in about 6 days after a spray (Rahman et al. 2011).
- Fish and water
- The label says spinosad is toxic to aquatic invertebrates, so keep it out of drains, ditches and ponds. NPIC rates it practically non-toxic to moderately toxic to fish, depending on the species, and very highly toxic to oysters.
- Pets and people
- Low toxicity to people and other mammals (NPIC). It can irritate eyes and skin, and it is the active ingredient in some flea medicines for dogs and cats. The labels carry no pet-specific directions.
- Plants
- Neither home label carries a plant-injury warning.
Use instead
- For caterpillars where parasitic wasps are working: Bt kurstaki, which kills only caterpillars and is rated low or no risk to parasites and predators by UC IPM.
- For thrips in a greenhouse or on houseplants: Amblyseius cucumeris sachets. If you have just sprayed spinosad, wait about 6 days before releasing them.
- For aphids where Aphidius are released: insecticidal soap, which UC IPM rates low for parasites. Soap works only on contact, and UC IPM rates its impact on natural enemies as short (hours to days).
- For Colorado potato beetle larvae: Bt tenebrionis where you can buy it, or hand-picking.
Other products
Sources
Bonide, Spinosad Concentrate / Captain Jack's Deadbug Brew label, EPA Reg. 4-471 (accepted 2012)
Spinosad 0.5% SC base label, EPA Reg. 62719-314 (2011); Monterey Garden Insect Spray is 62719-314-54705
NPIC, Spinosad General Fact Sheet (reviewed 2014)
UC IPM, Relative toxicities of pesticides used in floriculture and nurseries to natural enemies (2022)
UC IPM, Relative toxicities of insecticides used in tomatoes / cucurbits to natural enemies (2016)
Jones et al. 2005, Pest Manag. Sci. 61:179–185 (spinosad, Encarsia, Orius, A. cucumeris)
Rahman, Spafford & Broughton 2011, Pest Manag. Sci. 67:993–1003 (spinosad and predatory mites)
D'Ávila et al. 2018, J. Econ. Entomol. 111:1096–1103 (spinosad and Aphidius colemani)
Holt et al. 2006, Exp. Appl. Acarol. 38:141–149 (spinosad and Phytoseiulus persimilis)
Biondi et al. 2012, Pest Manag. Sci. 68:1523–1536 (review: spinosyns and beneficial arthropods)
Drafted from the cited sources, then checked claim by claim against those sources on 23 September 2026.
Always follow the label. Labels are legally binding; this page is not.