Safer® Brand 16 oz.Caterpillar Killer II Concentrate OMRI Listed® for Organic Use

Model #: 5163-6

7 reviews
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  • Kills caterpillars and worms.
  • Makes up to 32 gallons of solution from one 16 oz bottle.
  • OMRI Listed® and compliant for organic gardening use.
  • Contains B.t. Kurstaki.
  • Can be applied up to and on the day of harvest.
Safer® Brand Caterpillar Killer II– 16oz Concentrate with B.t.– How It Works Safer® Brand Caterpillar Killer Concentrate uses a naturally occurring bacterium to kill and control caterpillars and other leaf-eating worms. The caterpillars and worms that are damaging your plants will stop feeding immediately after ingesting the bacterium, which is known scientifically as Bacillus Thuringiensis var. Kurstaki (B.t. for short). Plus, when Caterpillar Killer is used as directed, it has no effect on birds, earthworms, or beneficial insects such as honeybees and ladybugs.

This economical concentrate is easy to mix into a ready-to-use solution. And, because Caterpillar Killer is OMRI Listed® and compliant for use in organic gardening, you know that you’re controlling leaf-chomping caterpillars in a way that fits into your organic garden plan.

Caterpillar Killer
Best used for:
Organic Gardening
Organic Gardening
Kill Caterpillars and Worms
Killing Caterpillars & Worms
Stops Feeding Damage
Stops Feeding Damage
Spares Beneficial Bugs
Spares Beneficial Insects
Economical Concentrate
Economical Concentrate
Caterpillar Concentrate Closeup

Say Goodbye to Caterpillars and Leaf-Eating Worms Fruits, vegetables, shade trees and ornamentals are all susceptible to the damage from worms and caterpillars. These nuisance pests will eat their way through foliage and cause irreparable damage to plants extremely quickly. That’s why it’s important to stop these caterpillars and worms right away with Safer® Brand Caterpillar Killer!

Target These Pests Use Safer® Brand Caterpillar Killer Concentrate to target these problem insects:
  • Tent Caterpillars
  • Gypsy Moth Caterpillars
  • Tomato Hornworm
  • Cabbage Looper
  • Imported cabbage Worm.
  • Bagworm
  • Spring Cankerworm
  • Fall Cankerworm
  • Elm Spanworm
  • Fall Webworm
tobacco hornworm
tomato with wormhole
Identify Damage Eliminate a variety of caterpillar & worm species. Visible damage from each will be different. Tomato hornworms eat entire leaves, stems, and the fruit of the plant, causing it to look like someone took a bite. Other worms, like tent caterpillars & fall webworms, form webs on trees & shrubs resembling white bags made of spiderwebs. Below these “tents” are dozens of caterpillars eating the leaves.
tent caterpillars
Caterpillars on Cabbage

B.t. to the Rescue Bacillus thuringiensis var. kurstaki is a naturally occurring bacterium that kills certain leaf-eating worms and caterpillars. Simply spray Caterpillar Killer onto trees, shrubs and vegetables so that worms and caterpillars eat the treated vegetation.

The bacterium includes a toxin that stops them from feeding or causing more damage to your plants. Within a few days, effected caterpillars and worms will die of malnutrition. Safer® Brand Caterpillar Killer can be used until the day of harvest, so you can protect your plants through their entire growth cycle.

Won’t Harm Beneficial Insects When Used as Directed Safer® Brand Caterpillar Killer controls and eliminates a variety of destructive caterpillars and worms. When used as directed, this treatment won’t harm birds, earthworms and beneficial insects, such as honeybees and ladybugs. These beneficial organisms are important to our ecosystem, and their survival is vital to the continued production of nutrient rich soil and the natural pollination process of flowers, fruits and vegetables.
won't harm beneficial insects
How to Use

How To Use Caterpillar Killer Mix caterpillar killer as directed to achieve desired amount of solution. Once Caterpillar Killer is sprayed onto plants and the treated vegetation is ingested by caterpillars and worms, feeding and damage will stop immediately. Keep in mind that more caterpillar eggs may hatch, so it’s best to monitor the area for newly hatched pests even after treatment. If more caterpillars are noticed, you may need to repeat the treatment again after 5-7 days. It’s recommended to apply Caterpillar Killer late in the afternoon or on cloudy days as B.t. can breakdown in excessive sunlight.

An Economical, Easy-to-Mix Solution This 16 oz bottle contains a concentrated solution that creates over 250 times that amount in usable caterpillar-killing solution. Simply mix a small amount of concentrate with water as directed until you reach the desired amount of solution. Store any unmixed concentrate in a cool place for later use. One 16 oz bottle of concentrate makes up to 32 gallons of solution and protects over 10,000 square feet of plantings.
Economical Concentrate
Omri Listed
Compliant For Use In Organic Gardening Safer® Brand Caterpillar Killer Concentrate has been third-party reviewed for use in organic gardening by Organic Materials Review Institute. It carries the OMRI Listed® seal, and it has been deemed compliant for use in organic gardening by the USDA’s National Organic Program. With Safer® Brand, you have an economical solution to get rid of caterpillar and worm pests in your garden while staying true to the organic gardening regimen that you, your family and your plants love.
Five Stars "I have tried several products to kill hornworms on my Royal Princess tree. This product stops hornworms caterpillars in their tracks. I have been losing plants for two years now until I found Safer®. It does not leave any noticeable residue on leaves like other products. A great product. Thank you!” (Review from Anonymous)  Read More Reviews »
Safer® Brand Caterpillar Killer Product Details Do you want to know more helpful details about Caterpillar Killer? Take a closer look at the in-depth specifications for this product. Complete Product Details »
Safer® Brand Caterpillar Killer Product Details
Model # 5163-6
Size 16 fl oz
Makes Up to 32 Gallons of solution
Active Ingredients B.t. - bacillus thuringiensis var Kurstaki 98.35%
Eliminates Caterpillars and worms
For Use On Trees, shrubs and vegetables
Learn More About Insect Pests Safer® Brand Caterpillar Killer eliminates leaf-feeding caterpillars and worms that eat and destroy the leaves and fruit of many trees, shrubs and vegetables. Check out some of our great resources to learn more about the destructive caterpillars that Caterpillar Killer eliminates.
About SAFER® BRAND Safer® Brand leads the alternative lawn and garden products industry, offering many solutions that are compliant with organic gardening standards. Safer® Brand recognizes this growing demand by consumers and offers a wide variety of products for lawns, gardens, landscapes, flowers, houseplants, insects and more! More About SAFER® BRAND »
Safer® Brand Caterpillar Killer Concentrate
Model # 5163-6
Size 16 fl oz
Makes Up to 16 gallons of solution
Active Ingredients B.t. - bacillus thuringiensis var Kurstaki 98.35%
  • Bagworms
  • Cabbage Looper
  • Elm Spanworms
  • Fall Cankerworms
  • Fall Webworms
  • Gypsy Moth Caterpillars
  • Imported Cabbage Worms
  • Spring Cankerworms
  • Tent Caterpillars
  • Tomato Hornworms
For Use On
  • Broccoli
  • Cabbage
  • Cauliflower
  • Celery
  • Collards
  • Kale
  • Lettuce
  • Melons
  • Mustard Greens
  • Ornamentals
  • Shade Trees
  • Tomatoes
  • Turnip Greens
Usage Notes
  • OMRI Listed® and compliant for organic production.
  • Apply at first sign of infestation.
  • Apply up to the day of harvest.
  • Spray leaf surfaces thoroughly & on top and bottom of leaves.
  • Follow individual application instructions.

Disclaimer: Safer® Brand does not endorse any information contained in product reviews. Please follow all label instructions for your specific use.

Most Recent Customer Reviews

Review Rate
Review posted on
May 4, 2021
Best stuff ever By John

Love this stuff. Safe yet protects my Burr Oakes, Pecan, Mountain Laurel, Thyme, Rosemary and anything else that bag worms infest. Works really quickly and stops them in their tracks.

Review Rate
Review posted on
August 22, 2020
Great! By raffaele23

Worked great on the bagworms on my arborvitaes. Fast shipping. Would definitely order from safer brand again.

Review Rate
Review posted on
May 25, 2020
This stuff works! By Happy Gardener
I love the safer products line of OMRI listed pest controls. The Bt with kurtsaki is effective when fighting the cabbage looper battle. Thanks for the free shipping!
Review Rate
Review posted on
May 8, 2020
Safer products always good organic treatment By herblover
I have not had to use the product yet, but based on my experience with other Safer products I feel comfortable in stating that it will perform as stated.
Review Rate
Review posted on
May 19, 2018
does the job By Pete

since I have been using Safer caterpillar killer I have had no problem with caterpillars eating my plants

Review Rate
Review posted on
September 27, 2017
Great product By Deboy

Had tried everything to get rid of the oleander caterpillars prior to using your caterpillar killer.....safer truly works!!!!!

Review Rate
Review posted on
August 2, 2017
best catipiller killer on the market By AL

When ever I have a catipiller problem I always use safer brand to get rid of the problem. It works perfect ever time

Read All Reviews (7) Write a Review
Q.Is the Caterpillar BT concentrate safe for dogs who play and lounge on the grass that the spray will be applied?

This product is not recommended for spraying on grass. It is intended for trees, shrubs, and vegetables. We recommend keeping children and pets away from treated areas until they dry.

Q.Can I just add fresh solution to an already mixed solution after 5 days? Does the already mixed solution contain any viable bacteria after a certain period of time?

Mixed solution should be used within 24 hours in order to retain the correct effectiveness.

Q.Can I store unused portions of the caterpillar killer in the refrigerator?

We do not recommend storing the product in the refrigerator, it will not extend the shelf life once opened.

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All About

All About Caterpillars in Your Garden

By learning about the many caterpillars that inhabit your veggie & fruit garden, you will find safe, effective methods of controlling them so you can have a healthy harvest without adding toxins to our environment.

Learn More:

Control Options

Control Options for Caterpillars in Your Garden


B.t. and pyrethrins are chemicals that can be used to help control the tomato hornworm, cabbage loopers and cabbageworms. B.t. (Bacillus thuringiensis) is an effective method of eliminating your garden or field of the tomato hornworm without environmental concerns or harm to birds and beneficial insects.

Insecticides containing pyrethrins can also be an effective method of controlling these caterpillars.


B.t. kills hornworm larvae, cabbage loopers and cabbageworms thereby preventing further damage. When the worm ingests the B.t., it works as a gut rot poison that makes the worm stop feeding. The tomato hornworm cabbage looper or cabbageworm will stop feeding immediately and die within days of malnutrition.

B.t. usually comes in a dust or concentrate and kills a variety of caterpillars and worms. It will not harm beneficial insects, birds, or earthworms when used as directed.

Sprays with pyrethrins paralyze the insects and result in their death.

Safer® Brand offers a variety of control products for tomato hornworms, cabbage loopers and cabbageworms to help control and eliminate these garden pests and revive your plants. Please check out our tomato hornworm, cabbage looper and cabbageworm control products for more details about how they work and how, when, and where they should be applied.

It is recommended with any pesticide to test plants for sensitivity to the product. Spray a small section of the plant in an inconspicuous area and wait 24 hours before full coverage.


B.t. is generally applied when it is a cooler time of day, preferably later in the afternoon or early in the evening since the product breaks down in sunlight and heat. Carefully read and follow all directions on the product's label.

When applying pyrethrins to infected plants, carefully read and follow all directions on the product labeling for safe and effective application. Do not spray plants in the peak of day or when temperatures exceed 90°F


Natural Predators


Tomato Hornworms

The parasitic wasp and green lacewings are two beneficial insects that help to control tomato hornworm problems. They can be attracted naturally to your cornfield or garden area where your corn is planted, and there are some companies that grow these insects and sell them to consumers.

Cabbage Loopers

Predators of the cabbage looper include lady beetles, spiders, pirate bugs, wasps, birds and small mammals.


A natural control method would be to entice parasitic wasps to your garden so these beneficial pests can help control the cabbageworm.


Tomato Hornworm

The parasitic wasp lays its eggs inside the tomato hornworm's egg. These have shown success rates of over 50% and higher. Upon hatching, the green lacewing larvae will eat the larvae of the tomato hornworm.

Cabbage Loopers

The predators and parasites of cabbage loopers attack both larvae and eggs, killing them for food as well as paralyzing them and depositing eggs in the larva or egg. When the parasitic egg has hatched, it will feed on the cabbage looper larva or egg.


The parasitic wasp lays its eggs inside the cabbageworm's egg. You can attract parasitic wasps by planting nectar and pollen producing plants in the garden or near crops.

If trying to attract these natural predators doesn't work, they can also be purchased from companies who raise them.


Plant the pollen or nectar producing flora as soon as possible according to the temperature of your area. Most local greenhouses and garden centers can help you determine the right planting time.

Contact a company that raises beneficial insects to find out when they should be purchased and released for maximum hornworm control.


Environmental Controls


Removing crop remnants, tilling the soil, and handpicking larvae are all methods that will help control these caterpillars. Using covers on rows of plantings of the cabbage family will not only help to keep out the cabbageworm but will also keep out the cabbage looper and other pests.


Handpick then destroy the caterpillars when you have found them. Remember not to disturb any caterpillars having white cocoons on their bodies. These are the pupae of the parasitic wasp. Place covers on rows of plantings according to the accompanying instructions or seek direction from your local home and garden center.


As soon as you find any of these caterpillars, just pick them off the foliage and destroy them, again taking care not to remove those with white cocoons on their backs. Use covers on rows of plantings of the cabbage family before the pest appear.


Expert Tips for a Beautiful Garden!

Gardening can be a very rewarding and healthy undertaking. By using organic products and methods, plants grow better, insect pests can be controlled, plant diseases can be eliminated, and lush harvests can be enjoyed!

Learn More:


FAQs About Insects in Your Tomato Garden


Q: My plant leaves look chewed! Do you know what type of insect might do that?

A: Insects that have the ability to chew plants must have special cutters in their mouths for this purpose. Such insects may include caterpillars, beetles, and grasshoppers, for example.


Q: If I use a floating row cover, how will bees and pollinating insects reach the plants?

A: They won’t be able to so you will need to pollinate them yourself by hand. Check with your local garden center or farm supply store to find out how to hand pollinate them. You may want to remove the row covers during times of insect pollination.


Q: How do I know if my plant is being attacked by an insect or a disease?

A: If it’s an insect, the plant may have holes in its leaves. Turn the leaves over and you may see the insects themselves clustered on the underside of the leaves. You may also see and feel a sticky substance if it’s an insect because the insect will leave a secretion on the plant.


Q: I have really big larvae in my garden, and my neighbor says they are Tomato Hornworms. They are attacking my tomatoes, peppers, and eggplants. How do I get rid of them?

A: B.t. (Bacillus Thuringiensis) is an excellent way to get rid of them without harming beneficial bugs. It actually works on most caterpillars. When the worm ingests the B.t., it works as a gut rot poison that makes the worm stop feeding. The tomato hornworm will stop feeding immediately and die within days.

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