Does Sevin Kill Bagworms? Quick and Effective Solutions

folder_openInsecta, Lepidoptera
commentNo Comments

Bagworms are a common pest that can cause significant damage to trees, shrubs, and other plants. One common method for controlling bagworms is using insecticides, and Sevin is a popular choice for many gardeners.

Sevin, which contains the active ingredient carbaryl, is effective at controlling bagworms when applied at the right time.

In order to eliminate these pests, it’s crucial to target them during their feeding stage in June and July, as this is when the insecticide can effectively penetrate the bagworm’s protective encasement.

Does Sevin Kill Bagworms
Bagworm we believe

What is Sevin and How Does it Work

Sevin’s Active Ingredient: Carbaryl

Sevin is a popular insecticide containing the active ingredient Carbaryl. Carbaryl is a chemical compound used for controlling and managing various invasive pests, including bagworms.

Mechanism of Action

Carbaryl works by disrupting the normal function of an insect’s nervous system.

It acts as a cholinesterase inhibitor, which means it prevents the breakdown of acetylcholine, a neurotransmitter responsible for transmitting nerve signals.

This accumulation of acetylcholine causes paralysis and eventually death of the pest.

Features of Sevin:

  • Contains Carbaryl as an active ingredient
  • Effective against a variety of pests
  • Can be used in dilution with water
  • Applied on the surface of soil and foliage

Characteristics of Carbaryl:

  • Cholinesterase inhibitor
  • Targets insect nervous system
  • Causes paralysis and death in pests

Pros of using Sevin:

  • Can control various invasive pests
  • Suitable for use on different plants
  • Can be applied in various ways, such as spraying or dusting


Cons of using Sevin:

  • May not be suitable for organic gardening
  • Potential concerns for human health and environmental impact

Here’s a comparison table of Sevin and another alternative, Bacillus thuringiensis (Bt), for bagworm control:

InsecticideActive IngredientMode of ActionSuitable for Organic GardeningEnvironmental Impact
SevinCarbarylCholinesterase InhibitorNoModerate
BtBacillusBiological ControlYesLow

Does Sevin Kill Bagworms?

Impact on Bagworm Life Cycle

Sevin primarily targets caterpillars during their feeding stage as they consume the foliage treated with the insecticide.

Optimal Timing for Application

Insecticides like Sevin should be applied after the eggs have hatched and small bags are seen on the trees.

Typically, bagworm eggs hatch from late May or early to mid-June. The ideal time to spray Sevin is during the spring season when the larvae are active.

To ensure effectiveness against bagworms, it’s advisable to treat weekly for 4 to 5 weeks.

Comparison: Sevin vs Handpicking

SevinCovers a wide area.Assumes correct timing with the life cycle.
HandpickingNo chemicals. Immediate results.Time-consuming and labor-intensive.

In summary, Sevin can be an effective solution for controlling bagworm infestations when used at the right time and applied consistently throughout the larvae feeding period.

Bagworm Cocoon

Application and Usage of Sevin

Sevin Insect Killer Concentrate

Sevin is usually available in the market as Sevin Insect Killer Concentrate for use on Plants, Trees, Soil and Lawns

Proper Mixing Ratios and Sprayer Types

To use Sevin Insect Killer Concentrate, mix properly as follows:

  • Mixing Ratio: 1.5 ounces of concentrate per gallon of water
  • Sprayer Type: Use a pump or hose-end sprayer

Timing and Frequency for Best Results

For effective control of bagworms:

  1. Apply Sevin within a few days of eggs hatching in late May or early to mid-June
  2. Follow up applications every 7 days, up to 3 times per year

Note: Sevin only kills pests present at the time of application, for continuous control, apply as needed.

Alternative Bagworm Control Methods

Biological Controls: Bacillus Thuringiensis and Predators

Bacillus Thuringiensis (Bt): A bacteria-based insecticide, Bt only affects certain insects and is safe for humans and animals.

It is effective against young bagworms but must be applied by mid-July1. Examples of Bt commercial brands include Dipel and Thuricide.

Predators: Certain predators can help control bagworm infestations. Examples of natural predators include ladybugs, bees, and wasps2.

Bagworm Cocoon

Chemical Alternatives: Malathion, Spinosad, Permethrin, and Bifenthrin

  • Malathion: Effective for various pests, including bagworms, spider mites, and aphids. Care should be taken to avoid harming bees and other beneficial insects3.
  • Spinosad: An organic compound, spinosad controls pests while being gentle on beneficial insects and the environment4.
  • Permethrin: Synthetic insecticide, permethrin, is effective for various pests like bagworms, spider mites, squash bugs, and scorpions5. Be cautious of its potential impact on beneficial insects like bees and ladybugs6.
  • Bifenthrin: A broad-spectrum insecticide, bifenthrin controls numerous pests, but may affect bees and other beneficial insects. Talstar is one brand of bifenthrin7.

Possible chemical alternatives to Sevin Insect Killer Concentrate:

MalathionEffective for various pestsHarms bees, beneficial insects
SpinosadOrganic, gentle on beneficial insects, environmentMay be less effective on some pests
PermethrinControls numerous pestsHarms bees, ladybugs, honey bees
BifenthrinBroad-spectrum insecticideHarms bees, beneficial insects

Non-Chemical Approaches: Handpicking, Soapy Water, and Removing Infested Branches

Handpicking: Light infestations of bagworms can be controlled by handpicking the bags from infested plants and destroying them8. Bags should be removed before the eggs hatch in June9.

Soapy Water: When bags are found in trees, pick the bagworms off and drown them in a bucket of soapy water10. This technique works best before eggs hatch in June11.

Removing Infested Branches: Cut the bags off the branches with scissors and destroy them12. This works best when the bagworms are actively feeding and spinning their bags13.


Environmental and Safety Considerations

Impact on Beneficial Insects and Wildlife

Sevin, a product containing the active ingredient carbaryl, is used to control a wide variety of insects.

However, it can also affect beneficial insects like honey bees, leading to a reduction in their populations.

Gardeners should apply Sevin only when necessary and consider alternatives that have a lesser impact on helpful bugs and predators in their garden.

Some points regarding Sevin’s impact on beneficial insects and wildlife:

  • Negatively impacts honey bees and other beneficial insects
  • Can disrupt the balance of predators in the garden ecosystem
  • Alternative insecticides might be less harmful to beneficial species

Risks to Humans and Pets

Carbaryl, the active ingredient in Sevin, has been associated with some health risks to humans and pets, such as skin irritations and nervous system disorders.

While Sevin is approved for use by the California Department of Food and Agriculture, it is crucial to follow the product’s safety guidelines, including wearing appropriate protective gear during application and keeping children and pets away from treated areas.

Key points to consider for humans and pets:

  • Possible skin irritations
  • Nervous system disorders
  • Follow safety guidelines and precautions

Proper Storage and Disposal

Proper storage and disposal of Sevin are essential for minimizing its impact on the environment. Store Sevin in a secure and cool place, away from heat sources or open flames.

Dispose of unused product and empty containers according to the manufacturer’s instructions and local waste disposal regulations to prevent contamination of water sources, soil, and harm to wildlife.

Some points on storage and disposal:

  • Store in a cool, secure place
  • Follow manufacturer’s instructions for disposal
  • Adhere to local waste disposal regulations



In conclusion, Sevin is a brand of insecticide that can kill bagworms by contact and ingestion. It has ingredients like zeta-cypermethrin and bifenthrin that target the nervous system of insects.

Sevin can be applied as a dust, a spray, or a granule, depending on the size and location of the infestation. This product should be used with caution, as it may harm the environment and beneficial insects.

For best effect, use the product in May and early June when the eggs hatch, and apply as many times as necessary to remove the bagworms because it works on application but not afterward


  1. Bagworms on Trees and Shrubs – University of Maryland Extension 
  2. Alternative Biological Control Measures 
  3. Malathion – Pesticide Information Profile 
  4. Spinosad – Pesticide Information Profile 
  5. Permethrin – Pesticide Information Profile 
  6. Permethrin effects on bees and ladybugs 
  7. Bifenthrin – Pesticide Information Profile 
  8. How to control bagworms on spruce tree 
  9. Bagworm caterpillar feeding 
  10. Bagworms – Purdue University 
  11. Bagworm caterpillar feeding 
  12. Control Bagworms With Insecticides in June and July 
  13. Control Bagworms With Insecticides in June and July 

Reader Emails

Over the years, our website, has received hundreds of letters and some interesting images asking us about bagworms. Scroll down to have a look at some of them.

Letter 1 – Bagworms

Cocoons on my Mesquite tree
October 10, 2009
South of Tucson, Arizona. I have these cocoons all over one of my mesquite trees.
Rio Rico, Arizona


Hi Pam,
This is a species of Bagworm.  Bagworms are caterpillars of moths in the family Psychidae.  They are unusual in that the female never leaves her bag.  The bag is formed from silk and plant material by a growing larva that eventually pupates inside its bag. 

Adult males have wings but females are wingless.  The female emits pheromones and attracts a mate to her bag.  Her eggs are also laid in the bag.  BugGuide contains some wonderful information.


Letter 2 – Bagworm parks on handicapped sign

Interesting photo (and location) of a bag worm
Hi Bugman,
Thanks to your site, my brother & I are able to identify the insect in the attached photo! We found this bag worm outside of a Walgreens, attached to the “Handi-capped” parking sign.

I am amazed that it made it all the way up to the top of the sign without being destroyed by someone! Plus, not sure how it got it in the middle of a parking lot? Best,
Stacey Gee
Poughkeepsie, NY

Hi Stacey,
While the adult male moths of bagworms have wings, the females are legless and wingless and remain in the bag their entire life, laying eggs there after attracting a mate with pheromones.

If a female bagworm caterpillar chose that site for its cocoon location, it will surely guarantee her progeny will not survive as they will be too far from a food plant. If a male moth emerges, he will be able to fly away. This whole scenario gives one pause to think.

Letter 3 – Bagworms

Strange Cocoons
Hi, Bugman,
We have two unusual cocoons around our house in central Florida. They are dark, spikey, and about 2 or 3 inches in length. What kind of critter can we expect to emerge from them?

Hi Curious,
You have a type of Bagworm, probably Thyridopteryx sphemeraeformis. This is a type of moth that often infests conifers like arborvitae. The caterpillars form the protective bag and never leaves it. It then pupates in the bag. The female is flightless and remains in the bag after emerging, and the male which has wings searches her out to mate.

Letter 4 – Bagworms

My daughter found these cocoon like pods next door to my house. There where many pods (15 in all) around the pine tree and on the pine tree that looked very natural. I’m unable to tell her what they are. Can you please help in identifying the ponds.
Brooklyn N.Y.
Michael Caputo & Kids

Dear Michael,
You have Bagworms, Thyridopteryx ephemeraeformis. They are common but rarely become serious pests. According to The Golden Guide Insect book, “their history is strange. The wingless and legless female, after mating, crawls back into her ‘bag’ and lays hundreds of yellow eggs, which hatch in spring.

The young larvae feed on leaves of many kinds of trees, building their conical bags as they feed. Later they bind their bags to twigs (or in your case the brick wall) and pupate. The male emerges, seeks the female, and mates.” We have a Bagworm page with additional information.

Dear What’s That Bug,
My girlfriend and I are stumped on identifying a bug, or more accurately, a cocoon that has latched on to the outside of her home in central Texas. 3 weeks ago this creature was partially out of its shell, and dragging this strange looking cocoon along with him.

He then preceded to pull himself up a brick wall, and has been there without sign of life for 3 weeks now.
Can you help identify this strange looking creature?

Dear Mister Chris,
I appologize for the delay in your answer, but the photo was lost in the bowels of American Homebody while America’s Sweetheart was in Miami. I just received the image. You have a bagworm, Thyridopteryx ephemeraeformis.

The exact composition of the bag is dependant upon the host plant which can be any number of deciduous trees as well as the preferred coniferous trees. Juniper is a particular favorite. I have located some information on for you.

Bagworms feed on shade, orchard, and forest trees of nearly every kind, as well as many ornamental shrubs and perennials. Severe attacks are unusual. Since deciduous plants grow new leaves, damage to them is usually not serious. The growth of small or newly planted trees, however, could be slowed by leaf feeding.

Newly hatched larvae begin to spin silken bags around themselves shortly after hatching. The first evidence of infestation is the presence of 1/4 inch bags which are carried almost on end by the young caterpillars inside. As larvae grow, leaf fragments are added to the bag, which may reach a length of 2 inches by the end of summer.

The adult female moth is wingless and never leaves the bag. Adult males are small, grey moths with clear wings. Bagworms overwinter in the egg stage inside female bags fastened to twigs.

Eggs hatch in late May and early June, and larvae feed until late August or early September. Males emerge in September and mate with females through the bag entrance. You can also check out this website which has some great photos of the bagworm.

Letter 5 – Bagworms

”pine cone” cocoons in Pennsylvania
Location: Pittsburgh, Pennsylvania
December 1, 2011 1:37 pm
Dear Bugman,
I noticed these mini pinecone-looking cocoons growing on the back of a stop sign by my work. Could you help me identify what creature created these cocoons? Thank you very much.
Signature: Kyle Helal


Dear Kyle,
You have noticed the cocoons of Bagworms, a family of moths whose caterpillars construct bags from silk and foliage.  The caterpillar enlarges the bag as it grows, dragging around its home as it feeds. 

When it is time to metamorphose, the Bagworm retains its bag to house the pupa.  Female Bagworm Moths are flightless and mate in their bags.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
Tags: Bagworm

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *

Fill out this field
Fill out this field
Please enter a valid email address.
You need to agree with the terms to proceed