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If you have found small, cone-shaped bags hanging off your arborvitae, you already know the panic. Those bags are bagworm larvae, and they strip an evergreen fast. You can stop them with a spray that lists bagworm on the label, applied while the larvae are still young. This guide names the sprays that actually list bagworm on the label, explains how to time your application, and helps you pick the bottle that fits your yard.
I’m Min — the founder and writer behind Gadgets Feed. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Bagworms are beatable with the right bottle and the right timing, and the top pick here is a 4.7-star bifenthrin concentrate. Whether you are treating a single shrub or a whole windbreak of evergreens, this breakdown of the bagworm spray for arborvitae covers seven sprays that list bagworm on the label.
Our Picks at a Glance
How To Choose The Best Bagworm Spray For Arborvitae
Arborvitae is an evergreen with dense, layered foliage, which means the spray has to reach inside the canopy, not just land on the outside tips. A bagworm hiding in the middle of the shrub survives a lazy spray. A spray that only wets the outer tips leaves the inner larvae alive to keep feeding. So the first rule is coverage, and the second is timing.
Match the spray to the bagworm stage
A bagworm starts tiny, then builds a protective bag around itself as it feeds. Early in the season, before the bag hardens, a contact spray or a biological spray both work well. Once the bag is thick and the larvae are mature, a contact insecticide that hits the insect directly becomes the more reliable option. Match the spray type to the bagworm stage: contact insecticide for mature, bagged larvae, Bt or spinosad for young ones.
Read the label for the words “bagworm” and “OMRI”
The label is the contract. If bagworm is not printed on the target-pest list, the product was never tested or cleared for it. Look for the word bagworm on the label, and if you want an organic-approved option, look for OMRI, which stands for Organic Materials Review Institute. That listing means the product fits certified organic growing.
Concentrate versus ready-to-use
You get more spray volume from the same bottle when you mix a concentrate with water yourself, so each application costs less. A ready-to-use bottle skips the mixing step and is simpler for a couple of shrubs. Concentrate wins on cost per gallon for a hedge line; ready-to-use wins when you have one shrub and no mixing gear.
Quick Comparison
| Model | Best For | Active Ingredient | Volume | Form | Amazon |
|---|---|---|---|---|---|
| Wisdom Pro L&H 7.9% Bifenthrin Concentrate★ Best Overall | Whole-yard knockdown | Bifenthrin | 1 quart | Concentrate | Amazon |
| Monterey BT Concentrate with Measuring SpoonBest Value | Organic caterpillar control | Bacillus Thuringiensis | 16 fl oz | Concentrate | Amazon |
| Fertilome (16063) Spinosad Insecticide | Large evergreens and windbreaks | Spinosad | 32 fl oz | Concentrate | Amazon |
| Fertilome (16076) Spinosad Soap Ready to Use | No-mix convenience | Spinosad + Potassium Salts of Fatty Acids | 32 fl oz | Ready-to-Use | Amazon |
| Fertilome (16062) Spinosad Concentrate | Budget organic spraying | Spinosad | 16 fl oz | Concentrate | Amazon |
| Neudorff Indoor Plant Spray | Indoor and patio plants | Pyrethrins + Canola Oil | 32 fl oz | Ready-to-Use | Amazon |
| Fertilome (16012) Caterpillar Killer with Bt | Small garden beds | Bt | 16 fl oz | Concentrate | Amazon |
In‑Depth Reviews
1. Wisdom Pro L&H 7.9% Bifenthrin Insecticide Concentrate (Quart)
Our pick — over 4.5★ from 250+ verified ratings; the strongest balance of quality and price.
The quart of concentrate that turns a bagworm problem into a mixing job.
This is the bottle to reach for when the infestation has spread across the yard and you want to treat everything at once. The active ingredient is bifenthrin, a synthetic pyrethroid, which is a nerve-active insecticide that has bagworms on its labeled target list. That matters because the label is the legal proof the maker cleared it for bagworms. It is a quart-sized concentrate, so you dilute it yourself and stretch it across far more shrubs than a pre-mixed bottle.
What wins growers over is the value per application. As one buyer reports: “Use 4x per year and never have bugs in my house. It’s super cheap and easy to mix.” Mixed at roughly two ounces per gallon in a hand sprayer, that quart covers a lot of ground, and it also lists gypsy moth caterpillars, tent caterpillars, ants, fleas, and mosquitoes. So one bottle handles the arborvitae and the rest of the pest list in the same afternoon.
Here is the honest catch: this is a stronger, broad-spectrum insecticide, so it will not distinguish a bagworm from a beneficial insect it lands on. Spray carefully and time your application to avoid the pollinators. For a plant-killing moth larva, that trade-off is usually one people accept, but it is worth knowing before you mix your first gallon.
What earns the top spot
- Bifenthrin listed for bagworms on the label
- Quart concentrate mixes into many gallons of spray
- Also covers gypsy moth, tent caterpillar, ants and fleas
What to keep in mind
- You do the mixing and measuring yourself
- Broad-spectrum, so it catches insects beyond the target
Reach for this if: You are treating multiple arborvitae or a whole yard and want the lowest cost per application.
Think twice if: You want a fully organic, ready-to-spray bottle for a single shrub.
2. Monterey BT – Bacillus Thuringiensis for Organic Worm and Caterpillar Control Bundled with Measuring Spoon – Concentrate for BT Spray – 16 oz
The biological option that leaves bees and earthworms alone and still stops bagworms.
If you want to kill bagworms without blanketing the yard in a broad insecticide, this is the pick. The active ingredient is Bacillus Thuringiensis, known as Bt, which is a soil bacterium that only harms caterpillar and worm larvae that eat it. Monterey lists bagworm, gypsy moth, cabbage looper, fall cankerworm, and elm spanworm right on the label, and it is OMRI listed for organic growing. The maker states it has no effect on birds, earthworms, or beneficial insects such as honeybees or ladybugs when used as directed.
The 16-ounce bottle is a concentrate, and it arrives with a measuring spoon, so you do not have to guess your dosing. Reviewers lean on how simple it is to mix and spray, which is why ease of use shows up again and again as a reason people keep rebuying it. It works best when sprayed in the evening, since the bacteria are sensitive to sunlight, and it is a popular choice for protecting foliage on trees, vegetables, and ornamentals. For an arborvitae, coat every layer of the foliage so the larvae actually ingest it as they crawl and feed.
The trade-off is speed and patience. Bt is not a contact killer that drops worms on touch; it stops them from feeding and they die over the following days. Value is a split call among buyers, with some calling it a bargain and others noting the price has crept up. If you need to knock a heavy infestation down fast, a contact spray is the quicker route — but for organic growers who want to protect their pollinators, this remains the thoughtful choice.
Why growers keep it: It targets caterpillars and worms specifically, leaving the bees and earthworms in your garden untouched, and the included measuring spoon takes the guesswork out of mixing.
A fair warning: It is a slow, biological killer that needs evening application and a few days to show results, so it is not the bottle to grab for an emergency knockdown.
Suits you if: You grow organically and want to protect pollinators while clearing worms off your arborvitae.
Skip it when: The bagworms are already mature and you need them gone within hours.
3. Fertilome (16063) Spinosad Insecticide, Controls Leaf-Chewing Insects, 32 oz
The big-bottle organic concentrate for a windbreak full of evergreens.
For someone treating a long row of arborvitae, the deciding number is 32 fluid ounces of concentrate, because that one bottle mixes into the most spray of the organic options here. The ingredient is spinosad, which is a natural fermentation compound that attacks the insect nervous system and is OMRI listed for organic growing. Bagworm is printed directly on the target list, along with leafminers, borers, thrips, armyworms, tent caterpillars, and loopers. You dilute it at four tablespoons per gallon of water, so measure carefully and mix in a tank.
The proof that it works on the exact pest you are fighting is strong. Growers report complete kills on young bagworms crawling across mature eastern red cedar windbreaks, with bagworms about half an inch long wiped out within days. Owners also use it on apple crops and gardenias, and it lists both outdoor food crops and ornamentals. What makes the 32-ounce size the premium pick over the smaller bottles is the volume of mixed spray you get from one purchase, which matters when a single tall arborvitae can soak up several gallons.
The honest caveat: spinosad does not spare every insect, and one buyer notes it is best limited to targeted use because it kills insects indiscriminately. Spray it in the evening and avoid open blossoms where pollinators feed. If your priority is the lowest cost per gallon for a large planting, this larger concentrate beats the 16-ounce versions on pure mixed volume.
Strong points
- 32-oz concentrate stretches across a large planting
- Bagworm listed on the label and OMRI listed
- Proven kills on young bagworms on cedar windbreaks
Weigh these
- You mix it yourself at four tablespoons per gallon
- Not selective, so it can affect other insects it contacts
Made for: Homeowners with several evergreens or a windbreak who want the most mixed spray per bottle.
Look elsewhere if: You have one small shrub and would rather not mix anything at all.
4. Fertilome (16076) Spinosad Soap Insecticide Ready to Use, 32 oz
A pre-mixed spray bottle you can carry straight to the shrub and start treating.
When you would rather not measure, mix, and store a tank, this bottle is already made up and ready. It pairs two active ingredients — spinosad and potassium salts of fatty acids, a soap that helps the spray stick and break down the insect — and both carry the OMRI listing for organic growing. Bagworm and tent caterpillar are on the label, and it is designed for outdoor use on vegetables, trees, shrubs, flowers, fruits, and citrus, so an arborvitae fits right in. The 32-ounce bottle gives you a solid amount of spray without any measuring cups.
Owners like the finished look it leaves behind, noting it cleans the plant and gives the leaves a shine while going after a wide range of bugs on the plant and in the soil. The label tells you to wet every plant part thoroughly, including the undersides of the leaves, which is exactly what arborvitae needs, since bagworms tuck themselves deep in the canopy. For a couple of shrubs, the no-mix format makes the job fast and tidy.
The one thing to weigh is coverage versus bottle count. A ready-to-use bottle empties faster than a concentrate that you dilute yourself, so if you have a long hedge line, you may go through several bottles where the concentrate above would only need one. For a single infested arborvitae or a light touch-up, the convenience is worth it.
The everyday win: It sprays straight from the bottle, covers a wide pest list, and leaves foliage looking clean and shiny.
The trade-off: A pre-mixed bottle runs out faster than a concentrate, so a large planting could take more than one.
Best for: A single infested arborvitae and a gardener who wants zero mixing.
Not ideal if: You are treating a long hedge and need the most coverage per purchase.
5. Fertilome (16062) Spinosad Insecticide, Spinosad Bagworm, Tent Caterpiller & Chewing Insect Killer, OMRI Listed (16 oz.)
A 16-ounce concentrate bottle built around one job: chewing worms on outdoor plants.
This is the smaller sibling of the 32-ounce spinosad above, and it sells the same single active ingredient and the same OMRI listing in a compact 16-ounce concentrate. Bagworms and tent caterpillars sit right on the target list alongside leafminers, borers, thrips, armyworms, and sod webworms. You dilute it at four tablespoons per gallon, so a little goes a long way and the bottle stores easily in a shed. Because it shares the formula with the larger bottle, you can expect the same kind of result — you simply mix fewer gallons per purchase.
The reviews here center on natural, gentle insect control. Buyers report it clearing white bugs off a hibiscus that then pushed out new growth and flowers, and one grower used it for years in a battery-operated sprayer around the yard to keep pests off the house. It is the kind of product a local nursery points customers toward when they want an organic approach to chewing insects. For a moderate arborvitae problem, that track record and the OMRI listing are the reasons it earns a spot.
If your planting is large, the smaller 16-ounce bottle simply mixes less spray than the 32-ounce version, so you may refill more often. It is also a concentrate, so it needs measuring and mixing. Neither is a flaw — it is the trade-off of the compact size. For one or two shrubs, it is the economical organic pick.
Why it earns a spot
- Bagworm and tent caterpillar on the labeled target list
- OMRI listed for organic growing
- Compact 16-oz concentrate stores easily
Where it falls short
- Mixes less spray than the 32-oz version
- Concentrate means you still measure and dilute
Choose it if: You want an OMRI-listed organic spray for one or two arborvitae and a bottle that fits on a shelf.
Pass it by if: You are treating a long row and would be refilling constantly.
6. Neudorff Indoor Plant Spray Kills 100+ Listed Insects on Contact 32 OZ
A ready-to-use spray that pairs pyrethrins with canola oil and reaches a wide pest list.
This bottle is a good fit if you keep potted plants on a patio or bring plants indoors for the winter, where a stray bagworm or caterpillar might turn up on foliage. It combines pyrethrins, a botanical insecticide, with canola oil, and the maker lists bagworm, armyworm, cabbageworm, hornworm, and webworm among the many pests it targets. It is ready to use at 32 fluid ounces, and the label notes it kills all accessible stages of listed insects, including eggs. It is cleared for fruits and vegetables up to and including the day of harvest, and also for shrubs, trees, and houseplants.
What owners tend to mention is the low odor and the size of the bottle. The 32-ounce format gives you a generous amount of spray, and the smell is mild enough for indoor use. It kills many insects on contact, and several buyers describe quick results on fungus gnats and spider mites. There is also an honest split in the reviews: it works well on some soft-bodied pests but a few users found scale difficult to control. For a light caterpillar problem on a patio shrub, it does the job without a chemical smell.
The practical limit is that this is a contact spray, so it must hit the insect to work. Deep inside a dense arborvitae, that reach can be hard to manage, which is why it shines more on smaller plants you can fully wet. On a large outdoor evergreen, you would be better served by a concentrate you can mix by the gallon.
Where it shines: A ready-to-use 32-oz bottle with a mild odor, cleared for use right up to harvest day, and it targets eggs as well as adults.
Know the limit: It is a contact spray, so it only works where it lands, and some users found tougher pests like scale hard to control.
Great choice if: You need an indoor-safe, no-mix spray for patio or house plants with a light pest problem.
Not the one for: Large outdoor evergreens where you need gallons of mixed spray for full coverage.
7. Fertilome (16012) Caterpillar Killer Spray with Bt OMRI Listed, 16 oz
A small Bt concentrate for a couple of shrubs and a light worm problem.
This is the entry-level bottle for a small garden bed or a single arborvitae, and the size tells you that right away. It is a 16-ounce concentrate built on Bt, the same caterpillar-targeting bacterium as the Monterey bottle above, and bagworm is named on the target list along with tomato hornworm, cabbage looper, tent caterpillar, and gypsy moth. It is OMRI listed for organic growing, and the maker states it is not toxic to humans and pets and is selective, leaving non-leaf-eating insects unharmed. Mix one tablespoon per gallon for fruits and vegetables, or four tablespoons per gallon for shade trees and ornamentals.
Owners who grow food crops tend to be the most enthusiastic. One grower describes starting with half-eaten leaves covered in caterpillars mid-season and clearing the worms and leaf damage within two days of application. Others use it on gnats in the soil of indoor plants and call it the only solution that worked. For anyone treating a small planting on a budget, that combination of Bt selectivity and OMRI listing is the appeal.
The obvious ceiling is volume. At 16 fluid ounces, this is the smallest bottle here — noticeably smaller than the 32-ounce Neudorff spray, which holds twice the volume. So if you are treating a large arborvitae or several trees, you will run out and rebuy. It is also a biological Bt, so expect a few days for results, not an instant knockdown. For a light, early-season touch-up, it is the sensible budget choice.
What it does well
- Bt concentrate with bagworm on the label
- OMRI listed and selective toward caterpillars
- Simple to mix at one or four tablespoons per gallon
Set your expectations
- Smallest bottle here at 16 fluid ounces
- Biological action means a few days for results
Pick it when: You have one small arborvitae or garden bed and want a cost-conscious organic Bt spray.
Move on if: You need enough mixed spray to cover a large or tall evergreen in one session.
Understanding the Specs
Active Ingredient Type
The active ingredient is the thing that actually kills the bagworm, and it usually falls into two camps. A contact insecticide like bifenthrin acts on the insect nervous system and kills on touch or shortly after, so it suits a mature, established infestation that needs a fast knockdown. A biological option like Bt or spinosad works differently: the larva has to ingest it as it feeds on the treated foliage, and it stops eating and dies over the following days. Bifenthrin kills on contact for a fast knockdown; Bt and spinosad must be ingested and take a few days.
Form: Concentrate or Ready-to-Use
The form decides how much spray you get from a bottle. A concentrate is a strong liquid you dilute with water, so a modest bottle mixes into many gallons, which is why it is the choice for large plantings and windbreaks. A ready-to-use bottle needs no measuring and is simple for a single shrub, but it holds only the spray already inside it and empties faster. Check the label for the word bagworm on the target-pest list, and for an OMRI listing if you grow organically.
FAQ
When is the best time to spray arborvitae for bagworms?
What is the difference between Bt and spinosad for bagworms?
Do I need to cover the whole arborvitae, or just the top?
Is a bagworm spray safe for my pets and kids?
How many applications does it take to clear bagworms?
Can I use these sprays on other evergreens and shrubs?
Will a concentrate spray cost less per application than a ready-to-use bottle?
Do I need to spray bagworms again after the first treatment?
Can I spray bagworms while flowers are blooming nearby?
What should I do if my arborvitae already shows heavy damage?
Final Thoughts: The Verdict
For most homeowners fighting bagworms on arborvitae, the bagworm spray for arborvitae that earns the top spot is the Wisdom Pro Bifenthrin Concentrate, because it lists bagworm on the label, mixes into many gallons of spray, and covers the rest of the yard pests in the same afternoon. If you would rather keep things organic and protect your pollinators, reach for the Monterey BT Concentrate, which brings its own measuring spoon and targets caterpillars and worms specifically. And for a single arborvitae where you want zero mixing, the Fertilome Spinosad Soap Ready to Use is the bottle to grab. Whichever you choose, spray in the evening, soak every layer of the canopy, and expect the best results while the larvae are still young.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of September 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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