Baking soda is a cure for flower disease.

Bordeaux mixture is a mineral pesticide, which is recommended to be used in green fruit production. It has good control effect on pear ring spot, black spot and black spot. However, many fruit growers often operate improperly in the process of preparation and use, resulting in reduced efficacy and even phytotoxicity. The correct use of Bordeaux mixture in pear orchard is introduced as follows:

(1) The proportion of preparation: The best effect is to use copper sulfate, quicklime and water in the ratio of 1:4:2000 for Bordeaux mixture on pear trees. The adhesion ability of the solution can be improved by increasing the lime dosage properly. Each spray can last for 30~40 days. The whole pear growth period (April ~ September) can only be sprayed 3~4 times, and it has no adverse effect on the appearance of fruits and does not produce rust. But using traditional 1:2:200 Bordeaux mixture, each spray can only maintain 15~20 days, and easy to produce fruit rust. If the lime dosage exceeds 1:6:200 Bordeaux mixture, the photosynthesis of leaves will be affected and the efficacy will decrease.

(2) Preparation method: It is not advisable to use metal containers for preparing Bordeaux mixture, but wooden barrels, plastic barrels or porcelain. Lime should choose white, light, massive fresh lime, avoid using long-term powdered hair sponge lime. When preparing, dilute copper sulfate with 2/3 of water, stir fully to dissolve it, then prepare quicklime into concentrated lime milk with 1/3 of water, and then slowly pour diluted copper sulfate solution into concentrated lime milk, stirring while pouring, so that the prepared Bordeaux solution is sky blue colloidal suspension without precipitation.

(3) Application method: Bordeaux mixture is a protective fungicide, which should be used before the disease occurs, and should be carefully and evenly sprayed. The back of the leaves should be sprayed to the degree of dripping, and the branches should be rinsed. It is appropriate to apply 150 kg per mu of adult pear trees. Spray should be carried out from 9 a.m. to 4 p.m. on sunny days, avoid when there is dew on cloudy days, and use before rain in rainy seasons. The first application should be carried out 10 days after flowering, that is, as early as possible in mid-April. Bildo solution is an alkaline pesticide and should be used with it. Generally, it should not be mixed with other insecticides and fungicides to avoid phytotoxicity; and when using other insecticides and fungicides, it should be staggered with Bordeaux solution for 7~10 days, otherwise the efficacy will be reduced. However, Bildo liquid can be mixed with withdrawal agent, and can improve the efficacy.

However, in pear orchards using Bordeaux mixture for a long time, red spiders have a tendency to aggravate the damage, so 73% paracetamol 1800 times or 20% chlorfenicol 800 times should be sprayed once before using Bordeaux mixture from May to July.