Krosin Ag: Streptomycin + Tetracycline Bactericide
The "Gold Standard" Systemic Antibiotic for Bacterial Disease Control in Crops.
Krosin Ag (historically known as Streptocycline) is a specialized agricultural antibiotic formulation. It combines two powerful active ingredients—Streptomycin Sulphate (90%) and Tetracycline Hydrochloride (10%)—to fight devastating bacterial infections in plants.
Unlike standard fungicides, this Soluble Powder (SP) is fully systemic. It penetrates the plant's vascular system to cure deep-seated infections like Bacterial Leaf Blight in Rice and Canker in Citrus, offering protection that surface sprays cannot reach.
Why Choose This Product? Key Benefits
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Rapid Systemic Action: Absorbs quickly into leaves and travels through the plant (xylem) to reach hidden bacteria.
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Dual-Action Power: Streptomycin kills the bacteria, while Tetracycline stops them from reproducing (synergistic effect).
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Curative & Preventive: It can cure existing infections ("Kresek" phase) and prevent new outbreaks.
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Rain-Fast Formula: Quick absorption means it doesn't wash off easily during the monsoon season.
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Broad Spectrum Control: Effective against major plant pathogens like Xanthomonas, Pseudomonas, and Erwinia.
Technical Specifications
| Parameter | Details |
|---|---|
| Brand Name | Krosin Ag (Streptocycline) |
| Technical Name | Streptomycin Sulphate 90% + Tetracycline Hydrochloride 10% SP |
| IRAC MoA Code | Aminoglycoside + Tetracycline Class |
| Chemical Group | Agricultural Antibiotic / Bactericide |
| Formulation | Soluble Powder (SP) - Yellow to off-white |
| Toxicity Label | Blue Triangle (Moderately Toxic) |
How It Works: Mode of Action
Krosin Ag uses a "Search and Destroy" mechanism to eliminate bacterial colonies inside the plant tissue.
- Penetration: The Soluble Powder dissolves instantly in water. Upon spraying, it enters the plant through pores (stomata) and cuts (wounds).
- Ribosomal Blockade (The Kill): Streptomycin binds to the bacterial ribosome (the protein factory). It forces the bacteria to produce broken proteins, causing the bacterial cell to die.
- Growth Stasis (The Stop): Tetracycline blocks the addition of new amino acids. This stops the bacteria from multiplying, allowing the Streptomycin to finish them off effectively.
Note: This 90:10 ratio is scientifically proven to delay resistance development in pests.
Target Crops & Pests
| Crop | Target Pest(s) |
|---|---|
| Rice (Paddy) | Bacterial Leaf Blight (BLB), Bacterial Leaf Streak |
| Citrus (Lime, Orange) | Citrus Canker (Xanthomonas infection) |
| Vegetables (Tomato, Chilli) | Bacterial Spot, Bacterial Wilt |
Dosage & Application Guide
The Golden Rule: Always follow the "Dose per Acre" for accurate results. Krosin Ag is highly potent—small doses yield big results.
Dosage per Acre, Litre, & Pre-Harvest Interval (PHI)
| Crop | Dose (g / Acre) | Water (L / Acre) | Dose (ppm) | PHI (Days) |
|---|---|---|---|---|
| Rice | 6g - 12g | 100 - 150 L | 100 - 150 ppm | 14-20 Days |
| Citrus & Fruit | Depending on tree size | High Volume | 50 - 100 ppm | 30 Days |
| Vegetables | 6g - 12g | 150 L | 100 ppm | 7-14 Days |
*PHI = Pre-Harvest Interval: The minimum number of days to wait between the last spray and harvesting to ensure safe residue levels.
How to Apply: Best Practices
- Timing: Apply during early morning or late evening. Tetracycline is sensitive to sunlight (photolysis) and degrades if sprayed in harsh noon sun.
- Mixing: Can be tank-mixed with Copper Oxychloride (COC) for a powerful "Cocktail" spray against complex diseases. Ensure water pH is neutral (not highly alkaline).
- Coverage: Ensure thorough coverage of foliage. For Citrus Canker, spray during new flushes of growth.
- Safety: Always wear PPE (gloves, mask, goggles). Wash hands thoroughly after use. Do not handle with bare hands as it may cause allergic skin reactions.
Frequently Asked Questions
1. What is the mixing ratio for Rice BLB?
The standard field recommendation is 6g of Krosin Ag mixed with 500g of Copper Oxychloride in 150-200 liters of water per acre.
2. Can I use this for fungal diseases?
No. Krosin Ag is strictly an antibiotic for bacterial infections. It will not control fungal rusts or mildews unless mixed with a fungicide.
3. Why is the powder yellow?
The yellow color comes from the Tetracycline component. It is photosensitive, which is why the product must be stored in a cool, dark place.
4. What are the alternatives if this is unavailable?
Due to regulatory changes, farmers are switching to Kasugamycin, Copper Hydroxide, or biocontrol agents like Pseudomonas fluorescens and Bacillus subtilis.
5. Is this safe for honey bees?
Generally, Streptomycin is considered less toxic to bees than insecticides, allowing for use during pollination periods in apple orchards for Fire Blight control.
Safety & Disclaimer
Regulatory Warning: As of January 1, 2024, the use of Streptomycin + Tetracycline in agriculture has been prohibited in India to prevent Antimicrobial Resistance (AMR) in humans. This content is for technical and historical informational purposes only. Always use approved alternatives like Kasugamycin or Biocontrols. Always read and follow the instructions on the official product label. Use personal protective equipment (PPE) during application.
