Green copper, specifically referring to copper-containing compounds like Copper Oxychloride (often appearing greenish-blue), is primarily used in plants as a protectant fungicide and bactericide.
How Green Copper Compounds Work:
Copper Oxychloride and similar compounds aren't absorbed into the plant tissue. Instead, they form a protective barrier on the plant's surface. This barrier works in the following ways:
- Enzyme Interference: The copper interferes with the enzyme systems of fungal spores and mycelium (the vegetative part of a fungus), disrupting their ability to function and preventing infection. This process is typically irreversible.
- Preventative Action: Because it acts as a barrier, it's most effective when applied before a fungal or bacterial infection takes hold. It protects the plant from attack.
- Broad Spectrum: It can be effective against a wide range of fungal and bacterial diseases.
Examples of Uses in Plants:
Green copper compounds are used to control various plant diseases, including:
- Leaf spots: Prevents the spread and development of leaf spot diseases caused by various fungi and bacteria.
- Blights: Controls blights that can rapidly damage foliage.
- Downy mildew: Protects plants susceptible to downy mildew infections.
- Early and Late Blight: Useful in protecting potato and tomato plants.
Important Considerations:
- Not Systemic: Copper-based fungicides/bactericides are protectants, meaning they only protect the parts of the plant they directly cover. New growth will not be protected.
- Environmental Impact: Copper can accumulate in the soil, so use should be judicious and according to label instructions to minimize environmental impact.
- Phytotoxicity: In some plants, excessive application can cause phytotoxicity (plant damage). Always follow label instructions and test on a small area before widespread use.
