How to prepare and use Bordeaux mixture?

Bordeaux mixture is a copper bactericide with a wide range of applications and a long history. Although the preparation method is troublesome, it is a cheap and excellent fungicide because it can effectively control many diseases of fruit trees, with good effect and long duration. It has a good control effect on grape downy mildew, black pox, anthracnose and brown spot.

Bordeaux liquid with excellent texture is sky blue colloidal suspension, which is alkaline, relatively stable and has good adhesion. However, if it is left for too long, it will precipitate and crystallize, which will reduce the efficacy. So it must be prepared now, not stored.

The preparation method and use method are as follows:

Generally, the Bordeaux solution used to control grape diseases is 200 times that of lime, that is, 1 (copper sulfate): 0.5 (lime): 200 (water). It can also be prepared at the ratio of 1: 0.7: 240.

First, take 0.5 kg lime and 80 liters of water, fully stir and dissolve, and then filter to make lime milk for later use. Take 1 kg copper sulfate and 20 liters of water to fully dissolve copper sulfate (note that large crystals should be ground before dissolving), and filter with gauze for later use. Slowly pour the copper sulfate solution into the lime emulsion, so that the reaction can be carried out in alkaline medium, and keep stirring, and then let it stand for a period of time before use.

The prepared drug particles are fine and uniform, with slow precipitation and few clear water layers; Poorly prepared Bordeaux solution will precipitate quickly and have a clear water layer.