When battling tomato hornworms, selecting the right Bt concentrate can make all the difference. The Bonide Thuricide BT Concentrate stands out as the best overall choice for its reliable performance and ease of mixing. For organic gardeners seeking a larger quantity, the Captain Jack’s Bacillus Thuringiensis BT offers great value, while the Monterey BT Bacillus Thuringiensis is notable for its affordability. However, tradeoffs include concentration strength, packaging size, and application ease. Keep reading for a detailed breakdown of these options to find the best fit for your needs.
Open a free Amazon Business account
Business pricing, bulk buying and tax-exempt orders.
Create a free accountAs an affiliate, we earn on qualifying purchases.
Complete the kit
Key Takeaways
- The most effective concentrates tend to have higher purity and proven formulations for tomato hornworm control.
- Packaging size and ease of mixing significantly influence overall value and usability for different garden sizes.
- Premium options often offer more consistent performance but come at a higher price point.
- Organic gardeners should prioritize brands with proven safety profiles and organic certification claims.
- Ease of application varies; some concentrates include handy tools like spoons or pre-measured bottles to simplify use.
| Bonide Thuricide BT Concentrate, 8 oz Ready-to-Mix Solution for Caterpillar, Moth and Worm Control |  | Best Overall for Versatility and Speed | Volume: 8 oz | Active Ingredient: Bacillus thuringiensis | Application: Ready-to-mix solution for spraying | VIEW LATEST PRICE | See Our Full Breakdown |
| Captain Jack’s Bacillus Thuringiensis BT, 32 oz |  | Best for Organic Gardeners Seeking Larger Quantities | Active Ingredient: Bacillus thuringiensis | Size: 32 oz | Application: Ready-to-use spray | VIEW LATEST PRICE | See Our Full Breakdown |
| Bonide Thuricide BT Concentrate, 16 oz Ready-to-Mix Solution for Caterpillar, Worm and Moth Control |  | Best for Organic Gardeners Needing Flexibility | Volume: 16 oz | Active Ingredient: Bacillus thuringiensis | Application: Ready-to-mix solution | VIEW LATEST PRICE | See Our Full Breakdown |
| Thuricide BT Conc 16oz |  | Best for Basic Organic Pest Control on Vegetables | Application: Concentrate, requires mixing | Volume: 16 oz | Active Ingredient: Bacillus thuringiensis | VIEW LATEST PRICE | See Our Full Breakdown |
| Thuricide Bt Concentrate 16oz |  | Best Certified Organic Choice for Versatile Pest Control | Volume: 16 ounces | Active Ingredient: Bacillus thuringiensis (Bt) | Suitable for: Vegetables, fruits, ornamentals, shade trees | VIEW LATEST PRICE | See Our Full Breakdown |
| Monterey BT Bacillus Thuringiensis for Organic Worm and Caterpillar Control, 16 oz |  | Best Overall for Organic Caterpillar Control | Type: Bacillus Thuringiensis insecticide | Volume: 16 oz | Organic Certification: OMRI Listed | VIEW LATEST PRICE | See Our Full Breakdown |
| Southern Ag Thuricide BT Caterpillar Control, 16oz |  | Best Value for Caterpillar-Specific Control | Size: 16 OZ | Type: Caterpillar Control concentrate | Application: Organic gardening | VIEW LATEST PRICE | See Our Full Breakdown |
| Monterey B.t. Caterpillar & Worm Killer, 8 oz with Spoon |  | Best Compact Size for Small Gardens | Volume: 8 oz | Application: Spray with trigger or pressure tank | Organic Certification: OMRI Listed | VIEW LATEST PRICE | See Our Full Breakdown |
| Monterey B.t. Bacillus Thuringiensis, 32 oz with Spoon |  | Best for Larger Gardens and Frequent Use | Size: 32 oz | Application: Mix with water, spray | Organic Certification: OMRI Listed | VIEW LATEST PRICE | See Our Full Breakdown |
| bt concentrates for tomato hornworm | Application | Volume | Active Ingredient |
|---|---|---|---|
| Bonide Thuricide BT Concentrat | Ready-to-mix solution for spraying | 8 oz | Bacillus thuringiensis |
| Captain Jack’s Bacillus Thurin | Ready-to-use spray | — | Bacillus thuringiensis |
| Bonide Thuricide BT Concentrat | Ready-to-mix solution | 16 oz | Bacillus thuringiensis |
| Thuricide BT Conc 16oz | Concentrate, requires mixing | 16 oz | Bacillus thuringiensis |
| Thuricide Bt Concentrate 16oz | — | 16 ounces | Bacillus thuringiensis (Bt) |
| Monterey BT Bacillus Thuringie | Spray or pressure tank | 16 oz | — |
| Southern Ag Thuricide BT Cater | Organic gardening | — | — |
| Monterey B.t. Caterpillar & Wo | Spray with trigger or pressure tank | 8 oz | — |
| Monterey B.t. Bacillus Thuring | Mix with water, spray | — | — |
More Details on Our Top Picks
Bonide Thuricide BT Concentrate, 8 oz Ready-to-Mix Solution for Caterpillar, Moth and Worm Control
This compact 8 oz concentrate stands out for its quick action and broad effectiveness against various caterpillars and worms. Compared with larger bottles like Captain Jack’s, it offers rapid results in smaller-scale gardens, making it ideal for seasonal use. Its ready-to-mix form simplifies application, but the smaller volume means more frequent reapplications are needed for ongoing protection. It’s best suited for gardeners seeking fast pest control without investing in larger quantities. However, it’s limited to specific insects and isn’t a broad-spectrum pesticide, so it won’t cover other garden pests. This pick makes the most sense for small to medium gardens that want quick, targeted pest control without complexity.
Pros:- Effective against a variety of caterpillars, moths, and worms
- Fast-acting, insects die within 2-3 days
- Easy to mix and apply as a spray
Cons:- Limited to specific pests, not broad-spectrum
- Requires frequent reapplication for ongoing protection
Best for: Home gardeners needing fast, effective control on a small scale
Not ideal for: Large-acre farmers or those seeking long-term, broad-spectrum pest solutions
- Volume:8 oz
- Active Ingredient:Bacillus thuringiensis
- Application:Ready-to-mix solution for spraying
Our verdict“This product is ideal for small gardens needing quick pest knockdown on targeted insects.”
Captain Jack’s Bacillus Thuringiensis BT, 32 oz
Compared with smaller bottles like Thuricide, Captain Jack’s offers a generous 32 oz size, making it better suited for larger gardens or extended seasons. Its ready-to-use spray is effective against worms and caterpillars and is safe for beneficial insects, aligning with organic gardening principles. While it requires thorough coverage and timely application, its larger volume reduces the need for frequent reordering. This makes it ideal for gardeners who want a more economical, organic solution for ongoing pest management. However, the need for complete coverage can be a challenge for uneven plant canopies, and it’s less convenient for small, quick treatments. Overall, this product is best for organic growers with more extensive pest control needs.
Pros:- Effective against worms and caterpillars
- Safe for beneficial insects and birds
- Organic gardening approved
Cons:- Must be applied at first signs of pests
- Requires thorough coverage for effectiveness
Best for: Organic gardeners managing larger plots or multiple plants
Not ideal for: Small-scale gardeners or those needing quick, targeted treatments
- Active Ingredient:Bacillus thuringiensis
- Size:32 oz
- Application:Ready-to-use spray
Our verdict“This product suits organic growers needing larger quantities and longer-term pest control on bigger gardens.”
Bonide Thuricide BT Concentrate, 16 oz Ready-to-Mix Solution for Caterpillar, Worm and Moth Control
Compared with the 8 oz version, this 16 oz concentrate provides a middle ground for gardeners seeking a balance of volume and convenience. Its organic formulation kills caterpillars, worms, and moths efficiently and is safe for beneficial insects, making it attractive for organic growers. The need to prepare the solution before application adds an extra step, which might be a minor inconvenience versus ready-to-use products like Captain Jack’s. It’s well-suited for gardeners who prefer flexibility in mixing and want a product capable of handling multiple pest types. On the downside, it requires timely application since it kills pests only through ingestion, making pest detection critical. Overall, this is a good choice for organic gardeners who want some control over application size and timing.
Pros:- Effective against a variety of caterpillars and worms
- Safe for beneficial insects and organic gardens
- Easy to prepare and apply
Cons:- Requires mixing before use
- Timing of application is crucial for effectiveness
Best for: Organic gardeners needing a versatile, mid-volume concentrate
Not ideal for: Gardeners seeking ready-to-use convenience or quick applications
- Volume:16 oz
- Active Ingredient:Bacillus thuringiensis
- Application:Ready-to-mix solution
Our verdict“This pick offers organic versatility and flexibility for gardeners comfortable with mixing solutions.”
Thuricide BT Conc 16oz
This 16 oz concentrate provides a straightforward option for controlling caterpillars and worms, especially for gardeners who prefer a traditional, organic approach. It’s effective and suitable for organic gardening, but the lack of detailed instructions on application frequency can be limiting, especially for newcomers. Its concentrated form requires mixing, which adds a step compared to ready-to-use products like Captain Jack’s, but it offers flexibility for different pest situations. It’s best for gardeners who already use Bacillus thuringiensis and want a reliable, no-frills solution. However, without specific guidance on reapplication intervals, users need to plan their pest control schedule carefully. This makes it better suited for experienced organic gardeners managing ongoing pest issues.
Pros:- Effective against caterpillars and worms
- Suitable for organic gardening
- Easy to apply as a concentrate
Cons:- Limited info on application frequency
- Requires mixing before use
Best for: Experienced organic gardeners familiar with Bt application routines
Not ideal for: Beginners or gardeners seeking a ready-to-use product for quick treatment
- Application:Concentrate, requires mixing
- Volume:16 oz
- Active Ingredient:Bacillus thuringiensis
Our verdict“This product is best for experienced organic gardeners who want a reliable, no-fuss concentrate.”
Thuricide Bt Concentrate 16oz
This OMRI-listed 16 oz concentrate offers peace of mind for organic gardeners targeting caterpillars and similar pests. Its certification ensures compliance with organic standards, making it suitable for those who prioritize environmental safety. While it requires mixing with water before application, its effectiveness against a broad range of pests makes it versatile across vegetables, fruits, and ornamentals. Compared with larger, non-certified options, this product provides reassurance of organic integrity, but the need for mixing and the limited pest spectrum mean it’s best for those who are already comfortable with Bt applications. It’s an excellent choice for eco-conscious gardeners managing a variety of pests organically.
Pros:- Organic certification (OMRI listed)
- Effective against caterpillars and pests
- Suitable for vegetables, fruits, and ornamentals
Cons:- Requires mixing with water
- Limited to caterpillars and similar insects
Best for: Organic gardeners seeking OMRI-certified pest control for multiple plant types
Not ideal for: Gardeners who prefer ready-to-use solutions or need immediate pest control
- Volume:16 ounces
- Active Ingredient:Bacillus thuringiensis (Bt)
- Suitable for:Vegetables, fruits, ornamentals, shade trees
- Organic Certification:OMRI listed
Our verdict“This product is ideal for organic gardeners prioritizing certified, versatile pest control with peace of mind.”
Monterey BT Bacillus Thuringiensis for Organic Worm and Caterpillar Control, 16 oz
This product stands out for its versatility and organic certification, making it the top choice for gardeners prioritizing eco-friendly pest management. Compared with Southern Ag Thuricide BT Caterpillar Control, it offers a broader pest spectrum, targeting worms, caterpillars, and several leaf-feeding pests. Its OMRI Listed status reassures organic growers, while the 16 oz size provides a good balance of application volume. However, it requires careful reading of the label to ensure proper use, and it is limited to specific pests—no broad-spectrum coverage. Its ease of mixing and application makes it ideal for those who prefer straightforward, organic pest solutions.
Pros:- Effective against a variety of pests including caterpillars, worms, and leaf feeders
- OMRI Listed for organic gardening, ensuring safety and compliance
- Safe for beneficial insects, earthworms, and bees when used properly
- Easy to mix and apply with spray equipment
Cons:- Requires careful reading of label to ensure proper application
- Limited to specific pests, not a broad-spectrum insecticide
Best for: Organic gardeners seeking a reliable, versatile insecticide for caterpillars and worms on vegetables and ornamentals.
Not ideal for: Gardening newbies looking for a quick spray solution without detailed label instructions, or those needing broad-spectrum pest control.
- Type:Bacillus Thuringiensis insecticide
- Volume:16 oz
- Organic Certification:OMRI Listed
- Application:Spray or pressure tank
- Target pests:Caterpillars, worms, cabbage looper, bagworm, gypsy moth, fall cankerworm, elm spanworm
Our verdict“This pick makes the most sense for organic gardeners who want a reliable, multi-target caterpillar control with minimal environmental impact.”
Southern Ag Thuricide BT Caterpillar Control, 16oz
Compared with the Monterey BT product, Thuricide offers a budget-friendly 16 oz container that is effective against caterpillars and worms, making it a favorite for cost-conscious gardeners. Its low toxicity to humans and pets enhances safety for edible crops, but it requires mixing and timely reapplications to maintain pest control. While it targets a limited pest range like Monterey, it lacks the broader pest spectrum of products like the Monterey BT Bacillus Thuringiensis. This concentrate is ideal for those who want an affordable, organic solution for caterpillars on vegetables or ornamentals, provided they are willing to apply it regularly.
Pros:- Effective against caterpillars and leaf-feeding pests
- Low toxicity to humans, pets, and edible crops
- Affordable 16 oz size suitable for multiple applications
- Safe for use on all plants and vegetables
Cons:- Requires mixing and reapplication for continued pest control
- Limited to caterpillar pests, not effective against other insects
Best for: Budget-conscious organic gardeners focusing on caterpillar control on vegetables and ornamentals.
Not ideal for: Gardeners needing broad-spectrum pest control or those who prefer ready-to-use solutions with minimal reapplication.
- Size:16 OZ
- Type:Caterpillar Control concentrate
- Application:Organic gardening
Our verdict“This product suits those seeking an economical, caterpillar-specific organic control that requires routine application.”
Monterey B.t. Caterpillar & Worm Killer, 8 oz with Spoon
This 8 oz bottle is perfect for gardeners with limited space or those who prefer smaller quantities. It effectively targets caterpillars and worms, similar to the larger Monterey BT Bacillus Thuringiensis, but its smaller size makes it more manageable for hobbyists or occasional use. Its OMRI Listed status ensures organic compatibility, and the included spoon simplifies measuring. The main tradeoff is the smaller volume, which may require more frequent reapplications for ongoing infestations. This product makes sense for gardeners who want an easy-to-handle, organic insecticide without purchasing a large container.
Pros:- Effective against caterpillars and worms
- OMRI Listed, safe for organic gardening
- Easy to measure with included spoon
- Compact size ideal for small gardens
Cons:- Requires frequent reapplication for ongoing pests
- Limited volume may not suit larger infestations
Best for: Small-scale gardeners or hobbyists with limited storage space seeking a targeted, organic pest control solution.
Not ideal for: Large garden owners or those managing persistent infestations who need higher volume or less frequent reapplication.
- Volume:8 oz
- Application:Spray with trigger or pressure tank
- Organic Certification:OMRI Listed
Our verdict“This pick is best for small gardens or occasional use, offering organic control in a convenient, compact size.”
Monterey B.t. Bacillus Thuringiensis, 32 oz with Spoon
Compared with the 16 oz Monterey BT, this 32 oz container offers more value for gardeners with larger plots or those who need frequent applications. It effectively targets caterpillars and worms, sharing the same OMRI Listing and organic credentials. The larger size reduces the need for multiple purchases, but it also means more storage space and initial investment. Its simple mixing process makes it accessible for regular use, though proper label adherence remains essential for safety and effectiveness. This product is ideal for experienced gardeners managing larger areas or persistent pest problems.
Pros:- Effective against a broad range of caterpillars and worms
- Large 32 oz size provides good value and fewer re-purchases
- OMRI Listed, safe for organic gardening
- Simple to mix with water for easy application
Cons:- Requires more storage space
- Initial cost higher than smaller containers
Best for: Larger garden plots or gardeners requiring frequent, ongoing pest management in an organic framework.
Not ideal for: Small gardens or casual growers who prefer smaller, less expensive containers or minimal application frequency.
- Size:32 oz
- Application:Mix with water, spray
- Organic Certification:OMRI Listed
Our verdict“This size makes the most sense for experienced gardeners with larger areas requiring regular, organic pest control.”
How We Picked
We evaluated these Bt concentrates based on several key factors that matter most to gardeners fighting tomato hornworms. Effectiveness against pests, concentration quality, and proven results were primary considerations. We also looked at packaging convenience, ease of mixing, and overall value—balancing price against performance. Brands with a reputation for consistency and organic compatibility received higher rankings, while those with less transparent formulations or cumbersome packaging were ranked lower. Our goal was to identify options suitable for both small and large-scale use, ensuring reliability and ease of application for different gardener needs.| bt concentrates for tomato hornworm | Active Ingredient |
|---|---|
| Bonide Thuricide BT Concentrat | Bacillus thuringiensis |
| Captain Jack’s Bacillus Thurin | Bacillus thuringiensis |
| Bonide Thuricide BT Concentrat | Bacillus thuringiensis |
| Thuricide BT Conc 16oz | Bacillus thuringiensis |
| Thuricide Bt Concentrate 16oz | Bacillus thuringiensis (Bt) |
| Monterey BT Bacillus Thuringie | — |
| Southern Ag Thuricide BT Cater | — |
| Monterey B.t. Caterpillar & Wo | — |
| Monterey B.t. Bacillus Thuring | — |
Factors to Consider When Choosing Best Bt Concentrates For Tomato Hornworms
Choosing the best Bt concentrate for tomato hornworms involves more than just brand reputation. Consider how much area you need to cover, your budget, and your experience with organic pest control. Concentration strength and formulation purity directly impact effectiveness, so avoid overly diluted products if you face persistent infestations. Ease of mixing and application tools can save time, especially for larger gardens. Also, verify whether the product is certified organic if that aligns with your gardening philosophy. Finally, consider how often you’ll need to reapply, as some concentrates last longer or require more frequent use.Effectiveness and Concentration
Not all Bt concentrates are equally potent against tomato hornworms. Higher concentration products generally provide faster and more reliable pest suppression, especially during severe infestations. Look for formulations with proven efficacy data or those recommended by organic gardening authorities. Lower concentration options may still work for light infestations but could require multiple applications, increasing labor and cost over time.
Packaging and Ease of Use
Packaging size and design influence how straightforward it is to prepare and apply the solution. Larger bottles or ready-to-mix concentrates save time in bigger gardens, while smaller bottles offer more control for small plots. Some brands include tools like spoons or pre-measured packets, which help prevent mixing errors. Avoid overly complicated packaging that complicates measurement or storage, especially if you’re new to using Bt products.
Price and Value
Price varies widely, but cost per application and total coverage area are better indicators of value. Bulk sizes often reduce the cost per ounce, making them ideal for larger gardens. However, if you only need a small amount, a smaller, more concentrated product might be more economical. Always compare the price against the concentration strength to determine which gives the best bang for your buck.
Organic Certification and Safety
If organic gardening is your priority, verify that the Bt concentrate is certified organic or approved for organic use. Organic formulations tend to be safer for beneficial insects, pets, and humans, but they still require careful application to avoid unnecessary exposure. Be cautious of products with added chemicals or preservatives that could compromise organic status or safety.
Frequency of Application
Some Bt concentrates require frequent reapplication, especially after rain or watering, while others last longer. Consider your garden’s climate and watering schedule when choosing a product. Products with longer residual activity reduce labor but might be more expensive upfront. Planning your schedule ahead will help you select a concentrate that balances effectiveness with convenience.
Frequently Asked Questions
How quickly does Bt concentrate work against tomato hornworms?
Bt concentrates typically begin to affect tomato hornworms within 24 to 48 hours after application. The bacteria interfere with their digestion, causing them to stop feeding and eventually die. The speed of effectiveness depends on the concentration used, the infestation level, and environmental conditions such as temperature and humidity. Reapplication may be necessary if rain occurs soon after treatment or if pests persist.
Can I use Bt concentrates on other garden pests?
Yes, Bt concentrates are effective against a variety of caterpillars, moth larvae, and other soft-bodied insects. They are especially useful for controlling pests like cabbage worms, armyworms, and cutworms. However, they are not effective against beetles, aphids, or other hard-bodied pests. Always check the label to confirm which pests the product targets and follow application instructions carefully to maximize results.
How often should I reapply Bt to control tomato hornworms?
Reapplication frequency depends on environmental conditions and pest pressure. In general, applying every 7 to 10 days is effective, especially during peak hornworm activity. After rain or heavy watering, reapplication is often necessary to maintain control, as the bacteria can be washed away. Consistent monitoring and timely treatments are key to preventing severe infestations.
Is Bt safe for beneficial insects like bees and ladybugs?
Bt is considered safe for most beneficial insects when used as directed, because it specifically targets caterpillar larvae and similar pests. It is most effective when pests are actively feeding, and it minimizes impact on pollinators if applications are made during early morning or late evening. Nevertheless, avoiding application during bloom or when pollinators are active can further reduce any unintended effects.
What should I look for to ensure Bt concentrate is high quality?
High-quality Bt concentrates should have clear labeling with active ingredient percentages and specific pest targets. Look for products with transparent formulation details and certifications if applicable. Reputable brands often provide tested, consistent potency and include instructions for best results. Avoid cheap or generic options without clear labeling, as they may contain lower concentrations or impurities that reduce effectiveness.
Conclusion
For gardeners seeking the best overall performance, the Bonide Thuricide BT Concentrate offers reliable results with straightforward application. Those on a budget or with larger gardens might prefer the Captain Jack’s Bacillus Thuringiensis BT for its value and quantity. Beginners should look for concentrates with clear instructions and included tools, such as the Monterey B.t. Caterpillar & Worm Killer. Organic growers prioritizing safety and certification will find the Monterey BT Bacillus Thuringiensis suited to their needs. Ultimately, your choice depends on garden size, budget, and whether you prefer convenience or maximum efficacy.
As an affiliate, we earn on qualifying purchases.College move-in / dorm season Picks
dorm essentials
