Bordeaux mixture


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Related to Bordeaux mixture: hydrated lime

Bordeaux mixture

(bôrdō`), fungicide consisting of cupric sulfatecupric sulfate
or copper (II) sulfate,
chemical compound, CuSO4, taking the form of white rhombohedral crystals or amorphous powder. It decomposes at 650°C; to cupric oxide (CuO).
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 and lime in water. Its fungicidal activity is associated with the slow formation of copper compounds, the ultimate toxicant being the cupric ion. It originated in France in 1885 and was widely used for spraying orchards, dusting crops, and treating seeds until c.1930. Since it was found that Bordeaux mixture frequently caused russeting of fruit, injured the leaves, and led to premature defoliation, it has been generally replaced by solutions made with powdered fixed copper. Sal soda Bordeaux, or Burgundy mixture, containing cupric sulfate and sodium carbonate (sal soda), was formerly used to spray small fruits but has been replaced by more convenient preparations. See pesticidepesticide,
biological, physical, or chemical agent used to kill plants or animals that are harmful to people; in practice, the term pesticide is often applied only to chemical agents.
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Bordeaux Mixture

 

a widely distributed chemical used against fungous and bacterial diseases of plants.

Bordeaux mixture is prepared on the day of use. One kg of blue vitriol is dissolved in 90 liters (7) of water. While these ingredients are being mixed, 10 1 of freshly prepared milk of lime is added. This causes the precipitation of basic sulfuric salts of copper in the form of a gelatinous precipitate that covers the leaves and fruits of plants effectively.

Bordeaux mixture is used most frequently to prevent grapevine mildew, apple scab, pear scab, and spots on stone fruits. The period and quantity of application depends on the biological characteristics of the cause of the disease and on weather conditions. Plants are sprayed with a 3–5 percent Bordeaux mixture (blue spraying) until the buds open. At the time of vegetation, a 0.5–1 percent solution is used. Bordeaux mixture should not be acidic, or it will burn the leaves. It is slightly poisonous.

Bordeaux mixture

[bȯr′dō ‚miks·chər]
(materials)
A fungicide made from a mixture of lime, copper sulfate, and water.
References in periodicals archive ?
Spray potatoes with Bordeaux mixture every two weeks until September as a precaution against potato blight.
Make your own Bordeaux mixture with 9oz of copper sulphate, 6oz of quicklime in five gallons of water.
ADRIENNE SAYS: Spray the tree with a copper fungicide such as Bordeaux Mixture in autumn before leaf fall, and again in January or early February before the buds swell.
You could also use a copper-based fungicide drench such as Traditional Copper, Cheshunt compound or Bordeaux mixture.
Follow up by spraying with a copper fungicide or Bordeaux Mixture in late summer and early and mid-autumn.
Always, as a matter of course, burn affected haulms and tubers otherwise they remain in the ground as the source of next year's infection Removing all blighted leaves will reduce the spread of the disease, but the best insurance if there is a whiff of blight about, or there are two days when the temperature does not fall below 10C and relative humidity stays above 75%, is to spray with Bordeaux mixture, or an approved proprietary brand early in July and thereafter fortnightly until the middle of September.
PINCH out tomato shoots and prevent blight in both tomatoes and potatoes by spraying with Bordeaux mixture.
You can spray with a copper fungicide in late winter and with Bordeaux mixture when the buds begin to swell.