Choosing the Right Bt: A Grower’s Guide to Certis Biologicals’ Portfolio

By The Certis Team

Products containing the bacterium Bacillus thuringiensis (Bt) are trusted biological tools that have been used for decades to manage lepidopteran (caterpillar) pests worldwide. Certis Biologicals offers one of the industry’s most comprehensive Bt product portfolios, with solutions tailored for a wide range of crops and geographies. Our Bt products fit seamlessly into IPM and resistance management programs with a suitable compatibility profile for use in tandem with predatory insects, beneficial mites, and crop pollinators.

How do Bt Products Work?:

The life cycle of Bt bacteria involves the production of insecticidal crystals and spores. When caterpillar larvae ingest Bt-treated plant material, these crystals dissolve in the alkaline midgut of the caterpillar, releasing and activating specialized proteins called Cry toxins. These Cry toxins bind to gut cells, disrupt digestion, and cause the larvae to stop feeding within hours. Death follows within several days. Because of the unique binding receptors in the caterpillar midgut and high pH requirements for Cry toxin activation, Bt products are highly specific to caterpillar pests without disrupting natural pest control organisms in your crops. 

Benefits of Bt in Pest Management:

• Resistance Management: Bt has no cross-resistance with synthetic chemistries, making it ideal for rotation or tank-mixing.
• IPM and Organic Compatibility: Many formulations are OMRI-listed and are compatible with conventional programs.
• Worker and Consumer Safety: Bt products have minimal pre-harvest intervals, no residue concerns, and are exempt from U.S. tolerance requirements.
• Environmental Stewardship: Bt products are highly selective, preserving pollinators, predators, and other beneficial insects and mites.
  
  

Key Bt Strains Used in Caterpillar Management:
To date, over 700 unique Cry toxins have been identified, allowing for highly targeted and flexible pest control. The two most common strains are Bt kurstaki (Btk) and Bt aizawai (Bta). 

• Bt kurstaki (Btk): Delivers broad-spectrum caterpillar control with Cry1A & Cry2A toxins.
• Bt aizawai (Bta): Expands activity with Cry1A, Cry1C, and Cry1D toxins, ideal for armyworm species and resistance concerns.
  
  

Certis Biologicals’ Bt Product Highlights:

• Agree® WG: A versatile hybrid Bta strain (GC-91) effective against resistant and non-resistant diamondback moths, loopers, armyworms, and grape defoliators.
  
  
• Crymax®: A high-potency Btk formulation designed to protect vegetable crops from armyworms, loopers, and other lepidopteran pests.
  
  
• Deliver®: The highest potency Btk available on the market. Ideal for use on tree fruit, nut crops, and grapes. Controls leafrollers, peach twig borer, and navel orange worm.
  
  
• Javelin® WG: Known as the “utility knife” of Btk products, Javelin delivers broad-spectrum control against loopers, diamondback moths, bollworms, budworms, and armyworms. Its flexibility makes it suitable across multiple crop systems.
  
  

Application Best Practices:

• Target early larval stages for maximum efficacy.
• Apply every 7–10 days, adjusting based on pest pressure.
• Ensure thorough spray coverage to maximize the amount of foliage treated
  with Bt.
• Keep tank mix pH below 9 to avoid deactivating Cry toxins before application.
• Rotate Btk (Javelin, Deliver, Crymax) with Bta (Agree WG) products, or tank mix with other bioinsecticides or compatible chemistries for resistance management. 

Backed by decades of field performance, Certis Biologicals’ Bt products offer precision pest control, safety, and peace of mind for growers. Whether you're managing worms in vegetables, grapes, or nut crops, Bt delivers a proven, sustainable solution.

Side-by-side comparison of beet armyworm larvae after 1 day on untreated
|diet (left) vs. Javelin^®-treated diet (right). The treated side shows minimal feeding and little frass, while the untreated side shows active feeding and heavy
frass accumulation.  

About Certis Biologicals

Certis Biologicals is the leading developer, manufacturer, and distributor of biological innovation such as biofungicides, bioinsecticides, bionematicides, bioherbicides, and plant health-promoting products, servicing the agriculture, turf, greenhouse, home, and garden markets globally. With a proven, broad portfolio of products and a continuous pursuit of new solutions for conventional and organic production, Certis Biologicals is a leader and partner in sustainable crop production trusted by farmers in the U.S. and more than 50 countries across the world. To learn more about Certis Biologicals and their portfolio of proven solutions, visit  CertisBio.com.