Blue Copper Fungicide (Copper Oxychloride 50% WP): Complete Guide (2026)
Walk into any agri input shop in Maharashtra, Karnataka, or Andhra Pradesh and ask for a copper fungicide — nine times out of ten, they'll hand you a blue packet and say "Blue Copper". It's not just a product name. It's become the generic term Indian farmers use for copper oxychloride fungicide, the same way "Dettol" became synonymous with antiseptic.
Blue Copper Fungicide (Copper Oxychloride 50% WP) is among the oldest, safest, and most cost-effective fungicides available in India — and one of the few that works on bacterial diseases as well as fungal ones. Here's the complete guide.
What is Blue Copper Fungicide?
Blue Copper is the popular trade name for Copper Oxychloride 50% WP — a contact fungicide and bactericide based on copper chemistry. The most widely available branded version is Crystal Blue Copper by Crystal Crop Protection, though dozens of manufacturers produce the same active ingredient under different labels.
The name "Blue Copper" comes from the characteristic blue-green colour of copper oxychloride — the same colour as verdigris on old copper statues or the Bordeaux mixture farmers have used since the 1880s.
Blue Copper is:
- A contact fungicide — sits on the leaf surface, kills spores on contact
- A bactericide — effective against bacterial diseases, unlike most synthetic fungicides
- Approved for organic farming under most Indian certification standards
- Zero resistance risk — copper's multi-site mode of action has never generated field resistance
- One of the most affordable fungicides per acre in India
How Does Blue Copper Work?
When Blue Copper contacts moisture (dew, rain, irrigation), it slowly releases cupric ions (Cu²⁺). These ions are toxic to both fungal spores and bacterial cells:
- They denature fungal enzymes and disrupt cellular metabolism at multiple sites simultaneously
- They damage bacterial cell walls and interfere with enzyme function
- They prevent spore germination on the leaf surface
The dual fungicidal and bactericidal activity is the key advantage over most other contact fungicides. Antracol, Mancozeb, and most synthetic fungicides simply don't touch bacterial diseases. Blue Copper does.
Being a multi-site inhibitor, resistance development is practically impossible — a pathogen would need to simultaneously mutate at multiple biochemical sites, which has never been observed after 140 years of copper fungicide use.
Diseases Blue Copper Controls
| Disease | Crops | Type |
|---|---|---|
| Late blight | Tomato, potato | Fungal (Oomycete) |
| Early blight (Alternaria) | Tomato, potato | Fungal |
| Downy mildew | Grapes, onion, cucurbits | Fungal (Oomycete) |
| Anthracnose | Mango, chilli, papaya | Fungal |
| Bacterial leaf blight | Paddy (rice) | Bacterial |
| Bacterial canker | Mango, citrus, tomato | Bacterial |
| Leaf spot (various) | Groundnut, tomato, chilli | Fungal |
| Rhizome rot / stem rot | Ginger, turmeric | Fungal + Bacterial |
| Die-back | Chilli, pomegranate | Fungal + Bacterial |
| Coffee leaf rust | Coffee | Fungal |
| Scab | Apple, pear, mango | Fungal |
| Citrus canker | Citrus (lemon, orange, mosambi) | Bacterial |
Blue Copper Fungicide Dosage
| Crop | Disease | Dose per litre | Dose per acre |
|---|---|---|---|
| Tomato / Potato | Early & late blight | 2.5–3 g/L | 500–600 g in 200 L |
| Paddy | Brown spot, bacterial blight | 3 g/L | 500–600 g in 200 L |
| Ginger / Turmeric | Rhizome rot, leaf spot | 3–4 g/L | 600–800 g in 200 L |
| Mango / Chilli | Anthracnose, bacterial canker | 3 g/L | Spray to run-off |
| Grapes | Downy mildew | 2.5–3 g/L | Spray to canopy |
| Citrus | Canker, scab | 3 g/L | Spray to run-off |
| Coffee | Leaf rust, brown blight | 3–4 g/L | Spray to run-off |
| General foliar | Broad-spectrum | 25–30 g per 10 L knapsack | — |
Practical Application Tips
- Apply preventively. Blue Copper cannot cure established disease — it protects healthy tissue. Start sprays before the disease season begins, not after lesions appear.
- Spray interval: 10–14 days in normal weather; shorten to 7 days during the monsoon or humid periods.
- Avoid spraying very young seedlings (under 4 leaves). High copper doses can cause leaf burn (phytotoxicity) on juvenile tissue.
- Don't mix with lime, soap, or highly alkaline formulations — these neutralise copper ion release.
- Excellent for ginger and turmeric. Rhizome rot (caused by both Pythium and Ralstonia bacterial wilt) is notoriously difficult to manage. Blue Copper's dual fungal + bacterial activity makes it one of the primary tools for these crops.
- Rotate with systemic fungicides for comprehensive disease management. Blue Copper as a preventive base; add a systemic (Roko, Tilt, Nativo) when disease pressure increases.
Blue Copper vs Other Copper Fungicides
Multiple copper-based fungicide forms are available in India. How does Blue Copper (Copper Oxychloride 50% WP) compare?
- vs Bordeaux mixture (copper sulphate + lime): Blue Copper is far easier to use — pre-formulated, consistent concentration, no on-farm preparation. Both provide copper-based protection.
- vs Cuprous oxide (Copper Sandoz): Higher concentration of available copper per unit weight; slightly different crop compatibility. Both are effective — choose based on availability and cost.
- vs Copper hydroxide (Kocide): Similar efficacy; Copper hydroxide has higher available copper content per gram. Both are broad-spectrum fungicide-bactericides.
For most Indian farming situations, Blue Copper (Copper Oxychloride 50% WP) provides the best value — widely available, inexpensive, and proven across decades of use.
Blue Copper Fungicide Price in India (2026)
- 250 g: ₹120–₹180
- 500 g: ₹200–₹280
- 1 kg: ₹345–₹500
One of the most cost-effective disease protection products available — a full-acre spray costs just ₹170–₹300, including bacterial disease coverage that more expensive synthetic fungicides cannot provide.
Buy Blue Copper fungicide on Farmkart with cash on delivery and delivery across India.
Frequently Asked Questions
Q: Is Crystal Blue Copper and Blue Copper the same product?
A: Crystal Blue Copper is a branded version of Copper Oxychloride 50% WP by Crystal Crop Protection. Multiple manufacturers produce the same active ingredient under different names — "Blue Copper", "Kocide", "Dhanucop", "COC 50", etc. The active ingredient and concentration are identical.
Q: Is Blue Copper safe for organic farming?
A: Yes — copper-based fungicides are permitted inputs under most organic certification standards including NPOP (India). Check with your specific certifier for usage limits.
Q: Can I mix Blue Copper with Mancozeb?
A: Yes — this is a commonly used tank mix for broad-spectrum preventive disease control. Both are contact fungicides that complement each other's disease coverage. Avoid mixing with strongly alkaline products.
Q: Does Blue Copper work on powdery mildew?
A: Limited. Copper has some activity on powdery mildew but is not the preferred choice. Use sulphur-based products or triazoles (Tilt, Nativo) for powdery mildew.
Q: Pre-harvest interval?
A: Generally 7–14 days depending on crop. Check the specific product label.
