Copper Sulphate (Sapphire 25%): Fungicide and Micronutrient Uses in Crops
Copper sulphate serves two distinct roles in crop management: as a micronutrient source correcting copper deficiency in soil, and as a fungicide controlling fungal diseases like blight, mildew, and rust on the plant surface — the application method differs depending on which purpose it's being used for.
As a soil amendment, Sapphire (25% Cu) corrects copper deficiency, which shows up as wilting, dieback of young shoots, and poor grain fill in cereal crops grown on copper-deficient soils, though true copper deficiency is less widespread than zinc deficiency across Pakistan's farmland.
As a fungicide, dissolved copper sulphate is applied as a protective spray on vegetables, fruit trees, and other disease-prone crops, working by inhibiting fungal growth on contact rather than being absorbed systemically into the plant.
Because copper sulphate is also used as an algaecide and can affect soil microbial activity at high rates, it's worth following label rates carefully and avoiding repeated high-dose applications to the same field year after year without a clear disease or deficiency justification.