1, Mulberry Powdery Mildew: In order to harm the leaves, small white mildew spots began to spread on the back of mulberry leaves, gradually expanded, often joined together, and finally covered the back of leaves. The surface of mildew spot is powdery, which is the mycelium and conidia of pathogenic bacteria.

In the later stage, small yellow particles appeared on the white mold layer and gradually increased, from yellow to black. On the leaf surface corresponding to the diseased spots, yellowish or even yellowish brown patches can be seen.

The disease is widely distributed and occurs in silkworm areas all over the country, especially in Hangzhou, Jiaxing and Huzhou in Zhejiang Province, which is prone to occur in summer and autumn.

2. Mulberry leaf disease: the disease occurs on the back of aging mulberry leaves. At the beginning, small pulverized coal black spots are produced. Yellow-gray or dark brown spots with the same size appear on the corresponding leaf surface, and the leaf surface changes color accordingly.

3. Mulberry brown spot disease: also known as leaf rot, leaf rot and scorch spot disease. It mainly harms mulberry leaves. At the beginning of the disease, dark water spots with sesame seed size can be seen on both sides of the leaves, and then they expand into nearly round dark brown spots. The spots continue to expand, and they are polygonal or irregular because of the veins, with dark brown edges and light colors in the middle, with a diameter of about 2-10 mm.

There are reddish powder lumps on the front and back of the lesion, and there are many black spots in the powder lumps, that is, the pathogen acervulus, which turns dark brown in the later stage and remains on the lesion. The color of the leaves around the lesion becomes slightly green and yellow.

4. mulberry bud Blight: Blight in mulberry bud mostly occurs near the winter buds on the branches in early spring, with dark brown, oily, rhombic or oval lesions around the winter buds, and the diseased branches are dry and wrinkled. Under rainy and humid conditions, the cortex rots and peels off easily, giving off an alcohol smell.

Shortly after the onset of the disease, small orange-red particles appeared on the lesion, which were arranged around the winter buds in a ring shape, making the winter buds unable to germinate. If the disease continues to develop, multiple diseased spots are interconnected and surround the branches for a week, and all the branches above the diseased spots will die.

5. Mulberry anthracnose: It mainly harms the middle and lower leaves of branches in autumn. Skin lesions are light brown to brown spots at first, and then expand into circular spots, surrounded by dark brown to reddish brown, with grayish yellow or light brown in the middle.

When the humidity is high or the rain is continuous, the diseased spots will swell, rot and perforate when exposed to water. When the weather is dry, the middle part of the lesion often cracks.

The short-line striped lesions on the veins, petioles and roots of seedlings are bright red to reddish brown, and brown to black rash particles are scattered on both sides of the lesions, which are sterile hairs of pathogenic bacteria.

After multiple diseased spots are fused, withered leaves will fall off. The seedlings were badly damaged.

6. Mulberry Sclerotinia sclerotiorum: Mulberry Sclerotinia sclerotiorum is a general term for hypertrophic Sclerotinia sclerotiorum, constrictive Sclerotinia sclerotiorum and granular Sclerotinia sclerotiorum. The perianth of hypertrophic Sclerotinia sclerotiorum is thick and swollen, grayish white, the disease model is enlarged, and there is a black sclerotium in the center. After the disease model was broken, it smelled bad.

Sclerotinia sclerotiorum is obviously reduced, grayish white, hard in texture, with dark brown spots on the surface, and black hard sclerotium is formed in the lesion. Sclerotinia sclerotiorum is an endophytic sclerotium.

The diseased pan is gray-black, easy to fall off and leave the fruit axis. Sichuan, Jiangsu, Liaoning, Zhejiang, Taiwan Province Province have all occurred.

7. Mulberry atrophy: atrophic atrophy, also known as hidden mulberry, leading mulberry, mussel mulberry and so on. , is an important disease of mulberry. The disease generally starts from a few branches and gradually spreads to the whole plant, which occurs in all mulberry planting areas.

The leaves with mild illness are small and shriveled, the leaves with split leaves are round, the branches are thin and short, the leaf order is chaotic and the internodes are short. Moderate infection, axillary buds germinate earlier at the top or middle of branches, some produce many lateral branches, and the whole leaves turn yellow, resulting in early autumn leaves and early spring buds without flower buds.

The seriously ill branches are thin and long, with small diseased leaves. When all branches of the whole plant are diseased, the diseased leaves at the top are about 6cm long, and finally the whole plant dies. It usually takes several years from onset to terminal symptoms.

Prevention and control methods: select disease-resistant varieties for strict quarantine, and prohibit the introduction of seedlings from the ward; Every two years, 1 spring shearing is carried out on the diseased plants, which has a rehabilitation effect on the slightly diseased plants; Treating the scion with warm soup, soaking the scion in warm soup at 55℃ for 10 minutes before grafting, and carrying out physical control can play a role in disease prevention.

Insect control and disease prevention: spray 10% imidacloprid wettable powder or 5% imidacloprid emulsifiable concentrate 2500 times every 30 days, with a total of 1 time, and control 1 time or twice.

8. Phellinus igniarius type atrophy disease: also known as atrophy disease, mulberry, cat ear, Taxus, etc. It is distributed in mulberry planting areas all over the country, and many areas have been devastated since the 1970s.

Most of them occur after summer logging, starting from the beginning of May and reaching the peak in June-August. The diseased trees died 2 ~ 3 years later, and the rate of seriously ill plants reached 60%, which forced the mulberry garden to be destroyed.

In light cases, the mulberry leaves at the top of mulberry branches shrink and become thinner, the veins become thinner, slightly curl backwards, the leaves turn yellow and axillary buds come out early.

In patients with moderate onset, the leaf contraction is more obvious, the backward curl is more serious, the yellow color is thick, the internodes are shortened, the leaf order is disordered, the side branches are small and numerous, and the mulberry fruit is not seated.

In severe cases, leaves are as thin as cat's ears, axillary buds keep sprouting, and branchlets are clustered like brooms. It usually starts from a single branch and then spreads to the whole plant.

Prevention and control methods: strengthen seedling quarantine and strictly protect mulberry fields without epidemic areas and diseases; Adopt virus-free technology to cultivate mulberry seedlings; Select and plant disease-resistant varieties suitable for the local area;

Strengthen the management of mulberry fields, such as spring cutting and rejuvenation, proper utilization of summer and autumn leaves, increased application of organic fertilizer, formula fertilization technology, scientific application of nitrogen, phosphorus and potassium fertilizer, enhance tree vigor and improve disease resistance; Spray drugs in time to eliminate poisonous insects and cut off the route of infection; Mulberry orchards with a diseased plant rate higher than 30% should consider removing the old diseased trees and replanting them.

9. Mulberry bacterial blight: it mainly harms new shoots and young leaves, causing leaf brown spots or rot and curl, terminal buds withering or new shoots blackening, reducing production by 20%.

There are two common types: black withered type and leaf shrinking type. Under the condition of high temperature and high humidity, the two types of infected sites overflow with yellowish adhesive-"overflowing pus", and after drying, the pus condenses into shiny beads or forms a biofilm.

Second, the main diseases of mulberry and their control methods

1. For newly planted orchards, the selected seedling varieties should be insect-resistant and stress-resistant, and the roots of fruit trees should be disinfected before planting.

For all orchards, it is very important to apply biological bacterial fertilizer in the soil, which can effectively inhibit harmful bacteria in the soil and reduce the probability of pests and diseases. When applying organic base fertilizer, we must pay attention to whether the organic fertilizer is decomposed, otherwise it will not only affect the fertilizer efficiency, but also increase harmful bacteria in the soil.

2. Ensure that the orchard has moderate humidity and transparent sunshine. The humid and closed environment is an important factor for the growth of bacteria. Pruning fruit trees in time can remove diseased branches of trees, ensure sufficient sunlight to penetrate the whole tree, and thus prevent diseases caused by bacterial infection.

3. After the mulberry leaves fall, the intertillage weeding should be timely, and the fallen leaves in the garden should be cleaned up in time. On the one hand, turning pests and germs in the soil to the surface during intertillage can partially freeze to death; On the other hand, the decay of litter will breed many germs, so we must pay attention to keeping the garden clean.

4. Use chemical agents to control diseases, and choose to apply them in advance according to the common diseases and the onset period of mulberry varieties in your garden. Don't wait until you are sick to treat, and don't blindly use all drugs, which leads to high cost of chemicals and excessive pesticide residues in mulberry fruits.