Among the time-tested drugs that effectively protect plants include the Bordeaux mixture. Its development dates back to the end of the 19th century, when the fungicidal effect of an aqueous solution of calcium hydroxide and copper sulfate was discovered.
Initially, the drug was used to treat vineyards, and later began to be used for spraying other green spaces.
When to use?
Bordeaux fluid in horticulture helps to effectively deal with most pathogenic lesions on the bark and leaves. In fruit crops after processing, a greater number of fruits ripen, and deciduous and conifers significantly intensify their growth. In places of removal of bark and on saw cuts of branches treated with Bordeaux mixture, rot crusts and darkened areas of wood will not form.
Use the mixture with caution, since copper compounds are toxic to humans. Processing of fruit trees is recommended for 2–4 weeks before harvest.
This increases the quality and durability of the fruit during storage, while reducing the residual concentration of copper on their surface. There is still controversy regarding the appropriateness of making the composition in the summer cottage during the growing season, since the components of the drug can get into earlier fruiting trees or shrubs.
Bordeaux fluid can lead to the appearance of a reticular structure of the fruit and a change in their size. This effect is especially noticeable on cherries. A win-win option is to treat the trees before budding. During this period, the mixture destroys most microorganisms at the initial stage. Do not confuse fluids for early garden treatment and used during the growing season. A high concentration of active substances from the first 3 percent solution will adversely affect the development of a plant that has already thrown leaves. For processing green plants using a 1 percent solution.
Composition and principle of action of the drug
The finished mixture is an aqueous solution of calcium hydroxide and calcium sulfate containing suspended copper hydroxide. The classical formulation of the drug includes three source components - copper sulfate, quicklime and water. The concentration of the solution refers to the content of the initially taken copper sulfate based on the final aqueous mixture.
The mechanism of action of Bordeaux fluid is the effect of residual copper ions on pests and fungi, occurring at the cellular level. The mixture is effective not only in the treatment of shrubs and trees, but also in flowers with affected inflorescences. The repellent effect of the composition on many harmful insects is noted, which the presence of the drug repels from damage to the plant.
A solution of pure copper sulfate would be much more effective if it were not for destroying the plant. Calcium compounds play the role of a binding component, neutralizing the negative effect of copper to an acceptable level.
For a person, a Bordeaux mixture is harmful. The main ways it enters the body:
- ingestion causes the most dangerous poisoning that can occur after working with the drug or eating contaminated fruits. Treatment consists of gastric lavage, ingestion of protein and saline solutions, as well as cardiac drugs;
- inhalation of aerosols causes a febrile state that lasts 2-3 days and is accompanied by bloating, tachycardia and nosebleeds.
If you suspect poisoning with copper compounds, you should call a doctor who will adjust the treatment and prescribe important stimulating drugs.
How to prepare the mixture at home without harm to health?
To prevent poisoning with a mixture is quite simple, if you follow the general recommendations:
- use a respirator, mittens, a hat and protective outer clothing when preparing and spraying the drug;
- do not smoke, drink or eat in between sprayings;
- do not spray the mixture in the immediate vicinity of fruits and vegetables, which will be collected within 2-3 weeks;
- always rinse the crop with water before use.
Keep in mind that during the spraying process, individual aerosol portions are dispersed tens of meters. The result may be the ingress of substances to trees and shrubs that are remote from the treatment site.
Home-made liquids
The scheme of mixing the components and obtaining the finished composition consists of several stages:
- the initial samples of copper sulfate and quicklime are dissolved with stirring in a small amount of hot water. A separate container is taken for each solution. Slaking lime is not carried out in plastic buckets, since they can melt, and metal containers are not suitable for dissolving copper sulphate and storing Bordeaux mixture;
- both solutions are diluted with water to a volume of 5 liters, after which they are mixed;
- a solution of copper sulfate is poured in a thin stream into a continuously stirred solution of lime;
- the finished mixture is an opaque suspension of blue color. Its suitability for processing plants should be checked by measuring pH with litmus paper. If an acidic medium is detected, a small amount of lime mortar must be added to the Bordeaux liquid. The readiness of the drug is indicated by a weak alkaline or neutral environment.
The colors of the litmus indicator: in a neutral environment - does not change color (yellow paper), in an acidic one - it acquires a crimson hue (some mistakenly consider it red), in an alkaline one - it shows a blue color.
The ratio of the components (on the final volume of 10 l):
- copper sulfate - 100 g (1% solution) or 300 g (3% solution);
- quicklime - 100 g (1% solution) or 300–500 g (3% solution).
After preparation, the drug should be used immediately (do not insist), until the finely dispersed particles of copper hydroxide are combined into larger conglomerates. Periodic mixing allows you to maintain a dispersed state of the solution. Long-term storage leads to sticking and precipitation of hydroxide particles, which will clog the nozzle of the sprayer. To keep the mixture for use for a couple of days, add 5-10 g of sugar to it.
The process of preparing and applying the liquid, see the video:
It will be cheaper to buy the ingredients for the Bordeaux mixture separately. A complete kit, including all components and litmus paper, is simpler but more expensive.
Features of application, dosage and consumption
A suspension of the drug is applied to the surface of plants in early spring and summer by spraying. The finished solution is poured into the tank, into which pressure is then pumped (manually or from a carbon dioxide cylinder). Spray the mixture evenly on trees and shrubs, trying to get the liquid on all sides of the leaves and branches.
Features of using the tool:
- the composition should be sprayed carefully, avoiding its spills on itself and on the ground;
- Before work it is necessary to make sure that there are no people in the spray zone without protective clothing (especially children) and animals;
- Do not carry out work with a high probability of precipitation;
- application should be done strictly in the wind.
The number of treatments is:
- before the appearance of the kidneys - 1 (3% solution);
- during the growing season - 3-4 (1% solution);
- the frequency of treatment (the duration of the liquid) is 10-14 days.
Mixture Consumption:
- for trees (fruit, berry, deciduous and coniferous) and large shrubs - 15–20 l per 100 m2;
- for medium shrubs and grapes - 10-15 l per 100 m2;
- for small bushes (strawberries, potatoes) - 5-10 liters per 100 m2.
Large trees with external signs of fungal infection can be sprayed with a 1% solution of the mixture at the rate of 10-15 liters per tree.
Liquid remains an effective and cheap drug for the treatment and prevention of diseases of green spaces. Its widespread use in horticulture is facilitated by the availability of components and the simplicity of self-preparation. The versatility of the tool allows for the joint processing of most plants and contributes to the overall improvement of the site.