Bordeaux broth
Bordeaux broth or copper lime broth was the first successful fungicide . It is a suspension of quicklime (CaO) or slaked lime (Ca (OH) 2 ) in an aqueous copper sulphate solution .
history
By importing vines from America to be resistant to phylloxera were, the causative agent of was in 1878 downy mildew of vine ( Plasmopara viticola ) introduced to southern France. From there it spread like an epidemic throughout France and led to great losses in yields in viticulture .
Pierre-Marie Alexis Millardet , professor of botany at the University of Bordeaux , was instrumental in importing the American vines. While looking for an effective remedy for downy mildew, he found that all the vines in a vineyard were infected, with the exception of the plants that grew directly along a path. According to the winemaker, these had been sprayed with a mixture of vitriol and milk of lime in order to discourage walkers from stealing the grapes due to their unsavory appearance and unpleasant taste. Millardet then made further experiments (mainly in the vineyards of Château Dauzac ) and published several papers in 1885 in which he recommended Bordeaux broth as a suitable means of combating downy mildew. In French usage, the method was called the Millardet David method , after Ernest David, the technical director of Château Dauzac.
Mode of action
The Bordeaux mixture contains Cu 2+ - ion , which in the fungal spores than enzyme poisons act and can prevent their germination. It has a protective effect, so it must be applied preventively.
Toxicity and Ecotoxicity
| safety instructions | |||||||||
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| Surname |
Bordeaux broth |
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| CAS number |
8011-63-0 |
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| EC number |
616-932-1 |
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| ECHA InfoCard | |||||||||
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Because of the quicklime it contains, Bordeaux broth is highly alkaline and, especially in undiluted form, can cause burns to the skin. In the event of an overdose, the treated plants will also be damaged.
Any residues of Bordeaux stock on fruits and vegetables pose no risk to the consumer. In these quantities they are not harmful to human health and are easy to wash off.
If Bordeaux broth is used over a long period of time, as is common in viticulture, copper accumulates in the soil. Then respond earthworms very sensitive. Leaching in ground and surface water plays only a minor role. Improper use leads to increased trickling of the vines. Dissolved copper compounds are very toxic to aquatic organisms.
Areas of application and approval situation
Bordeaux broth is used to combat downy mildew on vines. Its second important field of application used to be the control of late blight ( Phytophthora infestans ) of potatoes. It also acts as a repellent on some insects and has an ovicidal effect, so it can kill insect eggs.
Today, several preparations are approved in Switzerland that correspond in their composition to Bordeaux broth. They can be used there in viticulture against downy mildew and gray rot ( Botrytis cinerea ), in vegetable growing against Septoria leaf spot disease on tomatoes and celery, in berry cultivation and in fruit growing against scab and bacterial blight of the cherry.
In Germany and Austria, the Bordeaux broth is no longer permitted as a plant protection product. However, comparable copper-containing preparations with a similar field of application are available there.
Web links
Individual evidence
- ↑ a b Safety data sheet FIXA CUIVRE from Agro-Nutrition, accessed on September 7, 2018.
- ↑ Entry on bordeaux mixture; reaction products of copper sulphate with calcium dihydroxide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on September 7, 2018. Manufacturers or distributors can expand the harmonized classification and labeling .
- ↑ a b Directorate-General for Health and Food Safety of the European Commission: Entry on copper compounds in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; Retrieved February 19, 2016.