Latest Causes of Abnormal Winter Leaf Drop in Citrus and Control Measures

Citrus is one of the most common fruit trees in our lives. It is an evergreen fruit tree and rarely sheds its leaves in autumn and winter. Once abnormal leaf drop occurs, it will inevitably affect the yield and quality of the coming year. So what causes abnormal winter leaf drop in citrus? Let's take a look together.

I. Causes of Abnormal Winter Leaf Drop in Citrus

1. Nutrient deficiency

When citrus lacks nitrogen, phosphorus, potassium, and trace elements such as calcium and boron in winter, leaf yellowing and shedding can occur. This is one of the main causes of leaf drop in citrus at this time.

2. Water imbalance

When the soil is too dry, the growth of the plant's root system is inhibited. When the plant's transpiration exceeds the root system's absorption, the leaves will wilt and curl, and in severe cases the petioles will fall off. In addition, when water accumulates, the soil has poor permeability, which inhibits root respiration. Over time, the roots will rot, which can also cause yellowing and leaf drop of the aboveground branches and leaves, and in severe cases, plant death.

3. Poor light

The growth and development of leaves cannot be separated from photosynthesis. If the plant is too dense and light is insufficient, the inner canopy leaves will become larger and thinner. The leaf color becomes dull and even yellow. Winter light is already weak to begin with, and if it is not improved for a long time, it will cause a large number of inner canopy branches to drop their leaves.

4. Pest and disease damage

During the citrus growing period, red spider mites, scale insects, anthracnose, and yellow spot disease all cause the greatest damage, and if not controlled in time, they will cause a large number of leaf drops in spring and winter.

5. Other causes

In addition, pesticide damage, fertilizer damage, strong wind, freezing damage, and girdling may all cause abnormal leaf drop in citrus.

II. Control Measures

1. Strengthen tree vigor

In production, phosphorus and potassium fertilizers and organic fertilizers should be applied in combination with deep plowing so that the root system grows deeply. At the same time, foliar fertilizer should be sprayed, pruning should be reasonable, and drainage and irrigation should be timely, so as to cultivate strong tree vigor and improve the tree's resistance. For plants affected by pesticide damage, foliar fertilizer and brassinosteroid can be sprayed on the canopy branches and leaves to alleviate it. For leaf drop caused by improper girdling, foliar fertilizer should be sprayed in time or electrical tape should be used to cover the girdling wound. At the same time, within one month after girdling, avoid spraying pesticides such as lime sulfur mixture that easily cause leaf drop.

2. Do a good job in pest and disease control

Before overwintering, a comprehensive orchard cleanup should be done to reduce the base number of pests and diseases. Adding 2,4-D during orchard cleanup is beneficial for freezing protection and leaf preservation. For large numbers of leaf drops caused by anthracnose and yellow spot disease, once found, they should be controlled in time to reduce damage, and pesticides should be sprayed promptly during the growing season to protect the leaves.

3. Pay attention to freezing protection

In addition to measures such as planting in suitable sites, applying sufficient base fertilizer, and whitewashing tree trunks, in production attention should also be paid after fruit harvest to spraying for citrus winter leaf drop before freezing; second, emergency freezing protection measures should be taken. Before frost, potassium dihydrogen phosphate solution should be sprayed in time to slow the thawing of the tree body and restore leaf function.

4. Supplement nutrients

In production, attention should be paid to deficiency symptoms. Once found, control them in time, apply the right remedy for the condition, and apply whatever fertilizer is lacking.

  The above is an introduction to the causes of abnormal winter leaf drop in citrus and control measures. I hope it can help you. If you want to learn more related knowledge, please follow us.