Bordeaux mixture (Bordo mix)
Discovery
During 1878, grapevines imported from America in French vineyards began to show white downy spots at the underside of the leaves. The upper side of the affected region first became yellow and then turned brownish black and died. The disease was identified as downy mildew which was caused by Plasmopara viticola. Within 5 years of first appearance, the disease was spread in all vineyards of France and neighboring countries. The disease became so destructive that it threatened the grape production and wine industry.
A number of attempts were made to get rid of the disease, but nothing worked. One day, Pierre Alexis Millardet (a French Botany professor of Bordeaux University) while walking through the vineyards, observed a bluish film on the leaves of grapevines by the side of a dirty road. Interestingly these grapevines were free of any disease, in contrast to the other side of the road, where leaves were devoid of any blue films and affected by downy mildew. The owner of the vineyard told him that blue film of Copper sulfate (CuSO(4) mixed in hydrated lime (Ca(OH)2). It creates an impression to the passersby, if it is poisonous and not to take his grapes.
Professor Millardet with this information came back to the laboratory and tested different combinations of copper sulfate and hydrated lime to check the downy mildew. Finally, in 1885 he found an 8:8:100 combination of copper sulfate, lime and water best to control the downy mildew of grapes. This was named as Bordeaux mixture because it was invented in the Bordeaux region of France. It became the first established fungicide. Since then it is used throughout the world as an excellent fungicide, bactericide and algaecide as well.
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| P A Millardet |
A number of attempts were made to get rid of the disease, but nothing worked. One day, Pierre Alexis Millardet (a French Botany professor of Bordeaux University) while walking through the vineyards, observed a bluish film on the leaves of grapevines by the side of a dirty road. Interestingly these grapevines were free of any disease, in contrast to the other side of the road, where leaves were devoid of any blue films and affected by downy mildew. The owner of the vineyard told him that blue film of Copper sulfate (CuSO(4) mixed in hydrated lime (Ca(OH)2). It creates an impression to the passersby, if it is poisonous and not to take his grapes.
Professor Millardet with this information came back to the laboratory and tested different combinations of copper sulfate and hydrated lime to check the downy mildew. Finally, in 1885 he found an 8:8:100 combination of copper sulfate, lime and water best to control the downy mildew of grapes. This was named as Bordeaux mixture because it was invented in the Bordeaux region of France. It became the first established fungicide. Since then it is used throughout the world as an excellent fungicide, bactericide and algaecide as well.
Chemistry
The chemistry of the Bordeaux mixture is-
CuSO4 + Ca (OH)2 = Cu(OH)2 + CaSO4
Cupric hydroxide is the active principle of the mixture. Cu2+ in the Bordeaux mixture acts on enzymes of the fungal spores and inhibits germination. This means that it is to be applied as a preventive measure before the fungal attack.
CuSO4 + Ca (OH)2 = Cu(OH)2 + CaSO4
Cupric hydroxide is the active principle of the mixture. Cu2+ in the Bordeaux mixture acts on enzymes of the fungal spores and inhibits germination. This means that it is to be applied as a preventive measure before the fungal attack.
Application
Bordeaux solutions can be easily made by local farmers in different combinations. The solution is less toxic to the other commercially available fungicides. The solution is effective against vegetables including potato, chilli, tomato, fruits including lemon, orange, betel vine, ginger, flower and ornamental plant diseases such as downy mildew, leaf spot, leaf blight, damping off, anthracnose, canker, stem rot, foot rot, black spot, late and early blight, etc.
Carbendazim
Carbendazim (C9H9N3O2)
is broad-spectrum systemic fungicide. It belongs to the benzimidazole group of
antifungal compounds. Carbendazole, Bavistin, Mecarzole are synonyms of
carbendazim.
As, it is a systemic fungicide, it is absorbed by the roots as well as leaves of the plants and translocated in the entire plants very rapidly. It inhibits the cell cycle by binding to the tubulin and suppress the microtubule assembly. Thus, arrest G2-M phase of cell cycle and kill the cell (NCBI CID=25429). It inhibits the germ tube, appressorium and development of mycelium.
As, it is a systemic fungicide, it is absorbed by the roots as well as leaves of the plants and translocated in the entire plants very rapidly. It inhibits the cell cycle by binding to the tubulin and suppress the microtubule assembly. Thus, arrest G2-M phase of cell cycle and kill the cell (NCBI CID=25429). It inhibits the germ tube, appressorium and development of mycelium.
Application
It is used as both preventive and
curative to control the Ascomycetes, Fungi Imperfecti and Basidiomycetes
causing smut, leaf spot, rot, powdery mildew, anthracnose. It is effectively
used to cure the following plant diseases.
- Paddy (Blast disease, stem rot and false smut)
- Wheat (Smut diseases)
- Barley (Smut diseases)
- Cotton (Red rot, Collar rot, Anthracnose, Leaf spot)
- Pumpkin (Powdery mildew)
- Brinjal (Leaf sot, Powdery mildew)
- Apple (Scab)
- Grapes (Powdery mildew, Leaf spot, Anthracnose)
- Pea (Powdery mildew)
- Groundnut (Tikka disease)
- Mango (Malformation)
Sources
- National Center for Biotechnology Information. PubChem Database. Carbendazim, CID=25429, https://pubchem.ncbi.nlm.nih.gov/compound/Carbendazim (accessed on Apr. 10, 2020)
See also
Content first created on 01-05-2020
last updated on 04-09-2023
last updated on 04-09-2023
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