How to prevent elm rust? Common diseases of elm and their control

First of all, it is necessary to identify whether it is a disease or an insect infestation, and the possibility of leaf scabbing cannot be ruled out, but there is also a suspicion of scale insect damage. If you use your fingernails to gently scratch the rusty iron spots, if they are relatively easy to peel off and do not hurt the leaf epidermis, you can conclude that they are caused by scale insects, and the rust iron spots are scale insects. If you touch it with the tip of your finger, the rust-colored spots are raised, and there is an uneven feel, and if you scratch it with your fingers, it is easy to injure the epidermis, and the possibility of scabbing is great.

Scale insects: No matter what kind of scale insects they are, they can be wiped off with a damp cloth or removed with a small brush; If you can't remove it, you can try transparent adhesive pasting to remove it.

Drug prevention and control methods: bury 15 aldicarb systemic granules, dig a circle of 1 cm deep trench around the rhizosphere periphery in the pot, evenly sprinkle the granules, about 2 grams per pot, and then cover the soil and water enough, after 7 to 10 days can achieve a good insecticidal effect, or bury 3 carbofuran granules, 5 to 10 grams per pot, the effect is also good.

Sores and scabs: first form irregular cork rust spots on the leaves, and then gradually expand to russet, the general pathogen expands and multiplies and harms in the gap between the parasitic stratum corneum and epidermal cells, and is prone to bacterial spot blight, which makes the local tissue necrosis of the leaves and affects the flowering of the adult plant.

Prevention and control methods: At the beginning of the disease, spray the foliar surface with 20 of Tobuzin WP or 50 of carbendazim WP 1000 times, or use 50 of 800 times of antibacterial special WP or 50 of carbendazim WP 500 times to scrub the diseased leaves, which can effectively control the spread of lesions.

Identifying features of elm canker disease.

Infested elm trees usually occur in the cutaneous pores and pruning wounds, the initial lesions are not obvious, the color is dark, and the cortical tissue becomes soft and dark gray. After the onset of the disease, the bark tissue of the diseased part is necrotic, the damaged parts of the branches and Qingyu cadres become thin and sag, crack longitudinally, produce spots, grow into a circle, and the plants dry up and die. Small trees and seedlings die that year, and large trees die a few years later.

Prevention and control methods. 1. Never use diseased plants, burn them on the spot once the disease occurs2. Prune in time, prevent and control elm jumping elephants, and improve disease resistance 3. At the beginning of the disease, use 200 300 times of methyl tobuzin, or use 50% carbendazim wettable powder 50-100 times of liquid for prevention and control.

Identification characteristics of elm blight disease.

The initial symptoms are not significant, and there are no obvious symptoms when the cortex begins to decay, only the leaves on the twigs are wilted, the leaf shape is very small, and the skin can be peeled to see the symptoms of rot. After that, the skin loses water and shrinks, and small vermilion warts will grow. If the diseased skin wraps around the branches and stems for a week, it will cause the branches to wither and dry.

Prevention and control methods. 1. Pay attention to pest control, prevent frost and sunburn 2, prune branches in time, clean up diseased branches and diseased trees and dead standing trees 3, and prune ornamental trees in urban greening should be excessive. At the same time, remove dead branches, dead trees and diseased trees.

Identifying features of anthracnose in elm trees.

At the beginning of the disease, irregularly shaped lesions are produced on the leaves, light yellow or grayish-white, and later lesions produce black or black-brown granular protrusions, usually arranged radioactively. In severe cases, the leaves turn yellow and fall off early.

Prevention and control methods. Reduce infection**, cut off diseased leaves and branches in time, remove fallen leaves in Qingzhou, and destroy them in a centralized manner.

Drug control: When the leaves fall, you can spray 1:3:100 Bordeaux solution or 45% mancozeb 500 times solution.

The elm tree is the fastest growing tree among the five major tree species, with small leaves, beautiful shapes, soft and flexible branches, not easy to break, and well-developed root systems, which can be arbitrarily transformed to shape artistic carvings. Elm trees have the highest bud germination rate of any tree, and in early spring, they are covered with young shoots all over their bodies. Elm trees have a strong ability to heal wounds and do not leave visible marks after healing.

Elm trees are often infested with insect pests, and common elm pests include red spiders, elm oyster scales, and blowing scales. Elm trees are infested by spider mites, and their leaves are gray and dry leaves, which can be seen to be eroded into a web under sunlight. After the elm oyster scale damages the elm tree, the elm branches will be covered with white filaments, and the branches will be thin, and if they are not controlled for a long time, the whole branch will wither.

Another common disease is sun sickness, which is the main way to prevent and control this disease when exposed to strong sunlight, and proper bark protection is the main way to prevent and control this disease.

Identification characteristics: Adult: body length about 12 mm, wingspan about 25 mm.

The body and wings are white, while the tibiae and tarsal joints of the feet are orange-yellow. Eggs: oval in shape, grayish-yellow in color, the surface of the eggs is covered with grayish-black secretions, arranged in strings.

Larvae: Mature larvae are about 30 mm long and have a yellowish body. The larvae have white hair nodules on the dorsal surface of each segment, black around the base of the hair nodules, and large black hairy tufts on the 1st and 2nd segments of the abdomen.

Pupa: about 15 mm long, pale green, with black-brown hairs on the top of the head.

Identification characteristics of the green-tailed silkworm moth, adult: body length 35-40 mm, wingspan about 122 mm. The body surface has deep white hairs, the wings are pinkish-green, the wings have eye-shaped patterns in the center, and the hindwings have caudate-like protrusions, 40 mm long.

Eggs: spherical slightly flattened, 2 mm long, grayish-brown. Larvae:

It is about 80 mm long, yellowish-green, and has two red and yellow valve lines. The body segments have nodulous protrusions, the middle and hind thorax are four, the nodules have long brown and white hairs, non-venomous, pupa: body length 45 50 mm, russet.

There is a light-colored spot in the frontal area. Cocoon: oblong-ovate, grayish-yellow or grayish-brown.

Light booby-trapping is done with black light during the adult emergence.

Artificial control: Combined with maintenance management, the removal of egg masses and the centralized elimination of hatching cluster larvae are carried out to eliminate overwintering larvae and overwintering insect cocoons.

Biological control Pests are controlled by natural enemies such as native bees, wasps, and sparrows. The green-tailed silkworm moth will release red-eyed wasps during the egg stage, and the parasitic rate can be as high as 60% to 70%. In the early larval stage, it is necessary to spray 1500 2000 times of 25% chlorpyramide No. 3 suspension on the plants, and 400 600 times of the emulsion of Bacillus thuringiensis containing more than 10 billion spores per milliliter in the early larval stage.

Chemical control During the larval blooming period, it is necessary to spray 20% pyrethroid EC 2500 3000 times, or spray 20% pyrethroid EC 2000 times on the plants.

Answer: Hello, elm is a deciduous tree plant of the elm family Ulmus family, and the common pests are elm poison moth, elm phoenix moth, scale insects, longhorn beetle and goldenrod insects and so on. If you want to kill the insects on the elm tree, you can make your own sterilization solution to get rid of the insects. If there are fewer insects on the elm tree, you can spray the elm with vinegar solution, pepper solution or alcohol solution to remove insects.

If there are a lot of insects on the elm tree, you can use chemicals to remove the insects. Cut off the leaves of the elm tree, and after pruning, you can spray it with pesticides such as scavenging, pyrethroid, worm forest or dimethoate. Agent 7 can be sprayed 1 time in 10 days, and after spraying 3 or 4 times in a row, it can get rid of insects on elm trees.

If the insects on the elm tree are in the larval stage, they can be sprayed with Larvaura 3 or Bacillus thuringiensis. The agent is about 7 days, you can spray the elm 1 time, and after spraying 2 or 4 times, it can effectively remove the insects. In the later stage of maintenance, you can regularly spray elm with fungicides such as carbendazim or chlorothalonil.

During the maintenance period, the elm tree can be given sufficient light, water and fertilizer to make it grow healthily. If the elm tree grows well, it can improve its ability to resist diseases and insects. During the maintenance period, between 20 and 30 days, the elm can be sprayed with fungicide once, which can effectively prevent pests and diseases.