Fight fungi on your plants with Bordeaux mixture

Today’s agriculture has managed to preserve historical products such as Bordeaux mixture along with innovative phytosanitary products with pioneering active ingredients in technology.

The use of copper is still the order of the day due to its preventive activity against a wide range of plant diseases.

This, added to the fact that it can be used in organic farming, which is increasingly present in our daily lives, makes it a recognizable product that is loved by the farmer and gardener.

Our purpose in this article is to introduce you to the Bordeaux mixture, as well as its preparation to apply to all types of crops, doses and diseases that this agricultural product is capable of preventing and controlling.

WHAT IS BORDEAUX MIXTURE?

The Bordeaux mixture is born in France, a country with a long tradition in the vineyard. In fact, this crop is one of the most widely used sources of copper to prevent diseases such as mildew or those related to rot.

An eminently wine-growing area is Bordeaux, the place of origin of this copper-based fungicide. The mixture of cupric sulfate with hydrated lime (calcium oxide) gave rise to the so-called Bouillie Bordelaise.

Chemically, the name of this Bordeaux broth is cuprocalcium sulfate . From this mixture, a water-soluble powder is obtained that is generally used for foliar application, the vineyard being the main crop for use.

Its use is preferably indicated as a preventive , avoiding the sporulation of the fungus and creating a protective layer. Because it has problems to penetrate into the leaves and fruits, if the disease is in an advanced stage, it is advisable to use active ingredients of a curative type .

WHY ARE THE TWO SUBSTANCES MIXED?

Copper sulfate, when dissolved at the maximum concentration mixed with water, the pH result can be between 3 and 4, something considered quite acidic for foliar application.

Therefore, the farmers looked for a way to increase the final pH so that the treatment was in an optimal range, with a physiological pH between 6 and 8.

For this they managed to mix acidic copper sulfate with calcium hydroxide , an alkaline product, to achieve its neutralization and standardization of pH.

In addition, calcium not only has the advantage of neutralizing the acidity of copper, but it has also been shown to intervene in the resistance of the skin of fruits and leaves, reducing the possibility of fungal hyphae penetrating the plant tissue .

However, not all types of calcium have good absorption at the foliar level nor are they able to be absorbed by the leaves, but it does favor mixing with copper and its resistance to washing.

As a result, Bordeaux mixture concentrates up to 20% w / w copper metal, with better persistence and resistance to washing than other forms of copper, something very interesting when performing preventive treatments against fungi. 

Another interesting point about Bordeaux mixture is that it is a very economical product, since the source of copper sulfate is the one that has the lowest price compared to other forms such as copper oxychloride or copper hydroxide.

PREPARE HOMEMADE BORDEAUX MIXTURE

Although the highest and most stable concentrations are obtained from professional products with a phytosanitary certificate, in the past it was prepared at home, under the following recipe.

For every 100 L of water

  • Copper sulphate: 1 kg
  • Calcium hydroxide (quicklime): 0.7 kg

Due to its oxidizing nature, it was prepared in plastic vats.

HOW TO USE

Currently, Bordeaux mixture is subject to phytosanitary legislation, due to its copper content higher than 9% w / w. It is authorized for use in a large number of crops such as horticultural crops, stone and pip fruit trees, olive groves, ornamentals and, of course, grapevines.

DISEASES IT CONTROLS

The normal working dose in foliar application is between 0.6% and 1.25%, although it depends on the crop. This is equivalent to an amount of 600 to 1.25 kg / 100 L of water.

Bordeaux mixture is used effectively as a preventive and curative for the following diseases in crops.

TABLE OF DOSES, DISEASES AND SAFETY PERIOD

CultureDiseasesDose
it anthracnose, alternaria, mildew and bacteriosis600-900 g / hl
Almendro leprosy, monilia, mottling, screening and bacteriosis600-900 g / hl
Avellano monilia and bacteriosis600-1.000 g / hl
Eggplant alternaria, anthracnose, mildew and bacteriosis600-1.000 g / hl
Broccoli and cauliflower alternaria, anthracnose, mildew and bacteriosis600-1.000 g / hl
Onion anthracnose, alternaria ,, mildew and bacteriosis600-900 g / hl
Chalota anthracnose, alternaria ,, mildew and bacteriosis600-900 g / hl
Citrus bacteriosis, watery, fomopsis, endophytic fungi200 cc/hl
Cucurbits alternaria, anthracnose, mildew and bacteriosis600-750 g / hl
Stone fruit trees leprosy or dent, monilia, mottled, shot or screening and bacteriosis600-1.000 g / hl
Pome fruit trees monilia, mottle and bacteriosis600-1.000 g / hl
Garbanzo Rage600-1.000 g / hl
Pomegranate monilia, spotted, shot, or screening and bacteriosis600-1.000 g / hl
Green pea alternaria, anthracnose, mildew and bacteriosis600-1.000 g / hl
Green bean alternaria, anthracnose, mildew and bacteriosis600-1.000 g / hl
Higuera monilia, mottle and bacteriosis600-1.000 g / hl
Leafy vegetables alternaria, anthracnose, mildew and bacteriosis600-1.000 g / hl
Green bean alternaria, anthracnose, mildew and bacteriosis600-1.000 g / hl
Hop mildew. Dose of 600-1,000 g / hl. Security term600-1.000 g / hl
Quite monilia and bacteriosis600-1.000 g / hl
Olivar repilo and tuberculosis600-1.000 g / hl
Woody ornamentals leaf spots and rust600-1.000 g / hl
Potato mildew600-1.000 g / hl
Pistachio alternaria y bacteriosis600-1.000 g / hl
Tomato alternaria, anthracnose, mildew and bacteriosis600-1.000 g / hl
At mildew and bacteriosis600-1.000 g / hl

WHEN CAN WE APPLY THE BORDEAUX MIXTURE?

STONE AND PIP FRUIT TREES

The time of application depends on each crop. In general, in stone and pip fruit trees, the copper treatment is recommended from 50% discoloration of the leaf to swollen bud.

HORTICULTURAL CROPS

For the treatment of mildew, anthracnose, bacterial or alternaria in crops such as pepper, tomato or eggplant, Bordeaux mixture can be applied during all development phases. That is, from obtaining the first true leaves to fruit ripening.

The safety period in this type of crops is quite low, and is usually 3 days.

OLIVAR

In olive groves, the use of coppers is very common, and there is a current trend to apply solutions with high resistance to rain during autumn-winter. However, the use of Bordeaux mixture in olive groves is also allowed in the development of shoots until the coloring of the fruits.

USE ON VINE

In the vine it is commonly used as a preventive for mildew and bacteriosis, due to its high efficiency in the reproduction of these fungi.

You must bear in mind that it is not advisable to use Bordeaux mixture or any source of copper close to the harvest, since it could affect the future formation of yeasts involved in the fermentation of the wine.

Welcome to The GardenPure! My name is Ryan Heagle, and I’m the founder of The GardenPure, I spent the first part of my adult life teaching and then living in Australia in various business ventures, the first of which was a business devoted to the sale of house plants.  I am now a full time blogger. I am a self taught gardener.

Ryan Heagle

Welcome to The GardenPure! My name is Ryan Heagle, and I’m the founder of The GardenPure, I spent the first part of my adult life teaching and then living in Australia in various business ventures, the first of which was a business devoted to the sale of house plants.  I am now a full time blogger. I am a self taught gardener.

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