Prevention and treatment of rough skin disease of apple caused by protruding epidermis and cracked depression

In recent years, the rough skin disease of apple shows an aggravating trend, resulting in many dead branches and dead trees of apple trees, which seriously affects the quality, yield and benefit of apples. Many fruit growers have to dig trees to destroy gardens and destroy their own "money bags".

Apple rough skin disease

Symptoms: the rough skin disease mainly occurs on the apple branches, generally forming a rash-like dark brown protuberance with hard epidermis at the top of the new shoot, protruding from the phloem, occurring around the lenticels, slightly higher than the epidermis and without organisms. The small process gradually extends to the middle, base and trunk of the new shoot. In the later stage, the disease spot gradually expanded, cracked, sag, interlaced with each other. Scrape off the diseased skin, you can see black spots, black tendons, heavy up to the xylem, causing the death of branches and apple trees. The rough skin disease is also manifested in the tender leaves, the leaves become smaller, and chlorosis occurs between the veins and the margin. In apple orchards with severe rough skin disease, the leaves fall early in autumn and sprout late in early spring.

Second, the cause: excessive manganese, causing tree poisoning. The causes of excessive manganese are:

1. The soil is sour. According to the investigation, the pH value of apple orchards with severe rough skin disease is less than 7, and most of them are about 5.

2. The tree has a high content of manganese. The normal range of manganese content in apple leaves is 30,150 mg / kg, which is higher than 150 mg / kg, which is easy to suffer from rough skin disease.

3. The content of available manganese in soil is high. Rough skin disease is easy to occur when the content of manganese in soil of apple orchard is more than 10 mg / kg.

4. The content of soil organic matter is low. It is easy to develop rough skin disease when the content of organic matter in apple orchard is less than 0.6%.

5. The orchard is low-lying and the soil is heavy. Poor drainage, serious stagnant water, resulting in a large amount of soil manganese reduction, easy to develop rough skin disease.

3. Prevention and control measures:

1. For acid soil, quicklime should be applied, 200 kg per mu, or 150 kg calcium carbonate or calcium silicate fertilizer per mu, shallow hoe and watering to neutralize soil acidity. Do not use physiological acid fertilizers, such as ammonium sulfate, potassium chloride and so on.

2. No manganese fungicides and foliar fertilizer are sprayed on the leaves. The apple orchard needs to spray 11 times 12 organic fungicides every year. Do not spray mancozeb or mancozeb and fungicides containing these two ingredients, you can spray manganese-free fungicides such as hydantoin and methyl topiramate. Foliar fertilizer also does not contain manganese.

3. Do not use manganese-containing inorganic compound fertilizer in the soil.

4. Increase soil organic matter. Increase the application of high-quality soil fertilizer, more than 5000 kg per mu. 100 kg liquid humic acid was applied to apply fertilizer per mu. Plant grass between rows to make green manure. The tree plate is covered with grass, so that the content of soil organic matter is more than 1%.

5. Prevent stagnant water in apple orchard. The apple orchard should not be built on the waterlogged land as far as possible, and the flat land should dig a good drainage ditch to avoid stagnant water in the orchard, produce manganese reduction, cause manganese toxicity and aggravate the rough skin disease.