Burgundy mixture, named after the French district where it was first used to treat grapes and vines, is a mixture of copper sulfate and

sodium carbonate Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...

. This mixture, which can have an overall copper concentration within the range of 1% through 20%, is used as a fungicidal spray for trees and small fruits.Roberts, J. W.; Botanical Review. 1936, 2, 586.

History

Similar to the

Bordeaux mixture Bordeaux mixture (also called ''Bordo Mix'') is a mixture of copper(II) sulphate (CuSO4) and quicklime ( Ca O) used as a fungicide. It is used in vineyards, fruit-farms and gardens to prevent infestations of downy mildew, powdery mildew and other ...

, one of the earliest fungicides in use, Burgundy mixture, also known as “sal soda Bordeaux”, is used as a fungus preventative applicant on plants before fungi have appeared. Bordeaux mixture contains copper(II) sulfate, CuSO₄, and hydrated lime, Ca(OH)₂, while Burgundy mixture contains copper sulphate, CuSO₄, and sodium carbonate, Na₂CO₃. First used around 1885, Burgundy mixture has since been replaced by

synthetic Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to: Science * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic o ...

organic compounds, or by compounds that contain copper in a non-reactive,

chelated Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...

form. This helps to prevent the accumulation of high levels of copper in sediments surrounding the plants.

Synthesis and composition

Burgundy mixture is made by combining dissolved copper sulphate and dissolved sodium carbonate. Dissolved copper sulphate ratios generally range from 1:1 to 1:18. Sodium carbonate is generally added in higher quantities and at a dissolved ratio of 1:1.5. Over time, the sodium carbonate will crystallize out of solution, and the closer the copper sulphate to carbonate mixture is to 1:1 ratios, the faster this process occurs. This property is one key factor in the general discontinued usage of Burgundy mixture, as the mixture must be mixed shortly before intended utilization.Butler, O.; Bull. 1933, 56, 3.

Uses and mode of action

Burgundy mixture is used as a preemptive fungicide prevention for trees and small fruits. This occurs because the Cu(II) ions are capable of interfering with

enzymes Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

found within the spores of many fungi, preventing

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...

from occurring.Ramanathan, N., Sivapalan, A.; Journal of the National Science Council of Sri Lanka. 1986, 14(1), 145. Unfortunately, the mechanism for copper antifungal properties is not well understood, though it is thought that interactions between the copper and negatively charged portions of the cellular membranes of the fungi promote an altered shape and increased membrane permeability, which alters the homeostasis of the cell and can lead to insufficient uptake and storage of essential nutrients and ions.

References

{{reflist, 2 Copper(II) compounds Fungicides