What about the yellow leaf disease of apple trees?

Apple tree yellow leaf disease is a common disease of apple trees, also known as chlorosis, iron deficiency chlorosis and so on. The physiological diseases caused by lack of iron start from the young leaves of the new shoots, the mesophyll turns yellow first, the leaf veins remain green and reticulate, and in the later stage, the whole leaves become yellowish white, the leaves green are scorched, and finally the whole leaves die and fall early. Let's take a look at what to do about the yellow leaf disease of apple trees.

Causes of yellow leaf disease

When apple trees are cultivated in saline-alkali soil or excessive calcareous soil, yellow leaf disease is easy to occur, especially when alkaline soil moisture is too much, the disease is serious, the growth of fruit trees is exuberant, in case of continuous drought, the soil salt content is too high, the disease is serious, yellow leaf disease alleviates or disappears after entering the rainy season. Orchards with high groundwater level, low-lying land and heavy clay are easy to occur. Using Vitex mandshurica (mountain stump) as rootstock, yellowing is serious in saline-alkali areas.

Spraying compound iron fertilizer solution

In the preparation of compound iron fertilizer solution, 50 grams of citric acid was added to 50 kg water, 150 grams of ferrous sulfate was added after citric acid was dissolved, and fully stirred, and 100 grams of urea was added after ferrous sulfate was dissolved. The best spraying method is before 10:00 or after 4 o'clock in the afternoon. The fog point should be fine and the spray should be uniform and thoughtful.

Injection of fruit tree greening agent

The injection of fruit tree greening agent is suitable for more than 5-year-old large apple trees. the holes are first punched in the apple trees, with a diameter of 7 mm and a depth of 5-6 cm, usually with a 120-degree angle of the trunk per week, with 3 holes for each tree, clean the sawdust with wire hooks, and hammer the outlet interface of the sprayer into the drilled hole. Then the pedal sprayer is filled with 20 times of the diluted fruit tree greening agent prepared with distilled water or soft water (or 0.05-0.08% ferrous sulfate solution), which is connected with the outlet interface, and can be injected, and each adult tree can be injected with 1 liter, which can be appropriately reduced in the early fruit stage.

Increase the application of organic fertilizer to fruit trees

In the dormant period of fruit trees, it is better to control apple yellow leaf disease by mixing ferrous sulfate and organic fertilizer in proportion and applying organic iron fertilizer to the soil, or spraying compound iron fertilizer on the leaves in the early stage of growth, or injecting green agent into the trunk of fruit trees. Ferrous sulfate and high quality mature organic fertilizer were mixed evenly according to the ratio of 1 ∶ 15. During preparation, ferrous sulfate was dissolved in 10 times of water, and then ferrous sulfate solution was sprayed on organic fertilizer. First, dig a ring ditch along the periphery of the crown, with a depth of 50 cm and a width of 60 cm, then evenly apply the mixed organic iron fertilizer into the ditch and water it immediately after covering the soil. Generally speaking, big trees over 10 years old apply 80 kilograms per tree, and young trees less than 10 years apply 30 kilograms per tree. Organic iron fertilizer should be applied when base fertilizer is applied in autumn, or before fruit trees sprout, but not during the growing period, so as to avoid drug damage.