Thiodicarb in 2025: The Carbamate Insecticide's Global Retreat

1. Current Regulatory Status (July 28, 2025, 13:19)

Thiodicarb, a carbamate insecticide (IRAC Group 1A), has seen significant restrictions due to its high toxicity:

• Banned in the EU (2019), Brazil (2022), and China (2023)

• Limited Use in:

  • USA: Only for cotton bollworm (Helicoverpa zea) under EPA Section 18 emergency exemptions

  • India: Restricted to sugarcane borers with mandatory drone application

  • Australia: Phased out in favor of diamide alternatives

  
  

2. Key Concerns Driving Restrictions

• Human Health Risks:

  • WHO Class Ib (Highly Hazardous) – acute oral LD₅₀ = 66 mg/kg in rats

  • Cholinesterase inhibition risks for applicators

  
  

• Environmental Impact:

  • Highly toxic to bees (foraging LD₅₀ = 0.1 μg/bee)

  • Soil persistence: Half-life of 30–90 days (longer in alkaline soils)

  
  

3. Where Thiodicarb Persists (Legally & Illegally)

4. Resistance & Alternatives

• Resistance Hotspots:

  • Brazilian soybean loopers (40% reduced efficacy)

  • Indian pink bollworms (metabolic resistance)

  
  

• Emerging Replacements:

  • Diamides (e.g., chlorantraniliprole)

  • Biologicals (e.g., Bacillus thuringiensis strains)

  
  

5. Future Outlook

• 2026 Predictions:

  • USA may revoke emergency exemptions

  • India could ban if resistance worsens

  
  

• Legacy Issues:

  • Soil remediation needed in historical use areas

  
  

FAQ: Thiodicarb in 2025

Q: Can existing stocks be used in banned regions?

No—disposal via hazardous waste channels required.

Q: What PPE is mandatory for legal use?

Respirator + chemical-resistant gloves + full coveralls.

Q: Any detection methods for illegal use?

LC-MS/MS testing (detects residues at 0.001 ppm).

Key Action Items

1. Transition Planning: Adopt IPM strategies (e.g., pheromone traps)

2. Compliance Checks: Verify local regulations before application

3. Remediation: Use biochar to degrade soil residues

⚠️ Final Note: UNEP may classify thiodicarb as POPs candidate in 2026.