How to safely use Bordeaux liquid for fruit trees

Bordeaux mixture is a plant protection agent that is a suspension of copper sulfate and lime milk. The medicament is used for controlling fruit tree diseases, is economical, has simple use method, high control effect and good effect. However, if it is improperly formulated and used. It is extremely prone to phytotoxicity. Therefore, when formulating and using Bordeaux mixture, the following points should be noted:

First, strictly control the quality of lime and copper sulfate. When preparing Bordeaux mixture, choose white block, fresh and high quality quicklime; use blue-green, shiny copper sulfate crystal. Green or red copper sulphate contains impurities and should not be used. Because in the preparation of Bordeaux mixture, if poor quality lime or copper sulfate is used, it is easy to cause phytotoxicity and cause loss.

Second, carefully grasp the ratio of copper sulfate and quicklime. The active ingredient of Bordeaux mixture is basic copper sulphate, which is safer for plants. However, if an excessive amount of copper sulfate is used in the preparation of Bordeaux mixture, it is easy to cause phytotoxicity to plants. Therefore, the more lime content in the Bordeaux mixture, the safer the plant, and the stronger the adhesion of the agent, the longer the drug effect. However, the sterilization effect is slowed down and the control effect is reduced. On the other hand, when the lime content is too small, the efficacy of Bordeaux mixture is accelerated, and the control effect is improved, but at the same time, the phytotoxicity is correspondingly increased. Therefore, in the preparation of Bordeaux mixture, the ratio of copper sulfate to quicklime must be appropriate. If you are not sure, do not add more lime to ensure safe use. Fruit trees such as apples, pears, peaches, and persimmons are sensitive to copper sulfate and should be used with caution. The most commonly used ratio of Bordeaux mixture on apples is: 500 g of copper sulfate, 1500 g of quicklime (with no residue weight); the most common ratio of Bordeaux mixture on pear trees is: 500 g of copper sulfate, quicklime (with weight of dross) ) 2500 grams.

Third, pay attention to the occurrence of pear hibiscus. If the pear hibiscus is heavier and there is mucus on the leaves, spraying the Bordeaux mixture at this time will cause the leaves to fall off. Therefore, the heavier fruit trees of P. sylvestris should be thoroughly removed after the pear sap and mucus are completely removed.