Orchid fungicide-Bordeaux liquid

Bordeaux liquid is a protective fungicide with a long history, strong bactericidal power, wide application and long-lasting effect. it is made of copper sulfate, lime and water. The prepared Bordeaux liquid is sky blue, slightly sticky, colloidal precipitation is stable, and the suspension performance is good. The adhesion of spray on plants is very strong, and it is not easy to be washed away by Rain Water, and the residual period is 15-20 days. The main active component of Bordeaux liquid is basic copper sulfate. After spraying on the surface of plants, copper ions are gradually separated by plant secretions, carbon dioxide in the air and organic acids secreted during spore germination. Copper ions can cause the protoplast in the bacteria cells to coagulate and denaturalize and cause death.

The chemical reaction of Bordeaux liquid is as follows:

4CuSO4 ·5H2O + 3Ca (OH) 2 Murray-[Cu (OH) 2] 3 ·CuSO4 + 3CaSO4+5H2O

According to the ratio of copper sulfate to lime, Bordeaux solution is divided into equal (1:1), half-quantity (1:O.5), double-type (1:2), multi-dose (1RV) and small-quantity (1RV 0.25-0.4). The amounts of copper sulfate, quicklime and water for Bordeaux solution are as follows:

┌─┬───┬─┐

│ matching │ Copper Sulfate │ quicklime │ Water │ property │

│ │ (kg) │ (kg) │ (kg) │ │

├─┼───┼─┤

│ equivalent │ O.5 │ O.5 │ 50 │ can pollute plants with slow efficacy, no harm to plants and strong adhesion to │.

│ lime half-dose │ O.5 │ 0.25 │ 5 │ does not pollute plants, has fast efficacy, few drug damage, and strong │ adhesion.

│ lime double │ O.5 │ 1 │ 50 │ can pollute plants, slow efficacy, safety, no harm, strong adhesion to │.

└─┴───┴─┘

Bordeaux liquid can be prepared in two ways, one is the two-liquid method, in which copper sulfate and lime are dissolved in 1 stroke and 2 water respectively, and then the two solutions are slowly poured into the third container at the same time, stirring and mixing fully to form a sky-blue liquid. The second method is dilute copper and concentrated lime. First, dilute the lime with 1 beat 10 water, dissolve the copper sulfate with 9 + 10 water, then pour the copper sulfate into the lime solution and stir. Of the two methods, the former requires three kinds of containers, and the operation is more troublesome, while the latter is of good quality and easy to operate.

When preparing Bordeaux liquid, you should pay attention to the following: (1) do not use metal utensils; (2) it should be ready for use. Bordeaux liquid is sky blue after blending, and cannot be used if it turns green; (3) it cannot be mixed with soap, stone sulfur mixture and turpentine mixture; (4) high quality quicklime should be used, and if hydrated lime is used, it should be fresh and the dosage should be increased by about 30%; (5) the water temperature should not be too high, generally, it is better not to exceed the air temperature.

Bordeaux liquid should be used before or in the early stage of the disease, and the effect is better. It can be used to control orchid anthracnose, orchid leaf blight and other diseases. (Liu Zhongjian)