Chestnut blight is very common, what medicine is good for chestnut blight?

1st: January-February: (dormant; Flower bud morphological differentiation) Qingyuan, the main control object:

Mites, scales, etc. In terms of prevention, it is necessary to strengthen the drainage and humidity reduction in the field, and support the fruit in advance with a low fruit hanging positionIn the middle and late stages of the puffed fruit, timely medication can be used for prevention in case of rain, pyraclostrobin, difenoconazole azoxystrobin, etc., and prochloraz mancozeb + ethylphosphine aluminum plague cream can be used in the early stage of the disease.

Mainly harm the branches of young trees, the initial branches, young leaves appear water-soaked lesions, then the lesions expand to yellow-brown, the later disease gradually spreads downward, and eventually leads to the death of the branches, and in severe cases, it can lead to the death of seedlings. Citrus blight is caused by lower fungi such as Phytophthora and Phytophthora phytophthora, and those that infect the young shoots of seedlings at the seedling stage are called seedling blight, those that damage the base of the stem are called foot rot, and those that damage the branches and leaves and fruits are called blight rot (Phytophthora brown rot).

Nurseries with low-lying terrain and poor drainage are seriously ill, while nurseries built on gentle slopes with convenient drainage and irrigation are lightly ill; Plain paddy field nurseries are seriously ill, mountainous dry fields are mildly diseased, continuous cropping is easy to get diseases, and rotation nurseries or new nurseries are lightly diseased. Too dense, too dense planting is susceptible to disease; The disease is severe in humid and hot weather, and the germs spread quickly. The disease is serious in spring and autumn, and prevention should be strengthened. Preventive agents can be used mancozeb, iprodione and other ** agents can be treated with sprays such as enoylmorpholine or methafen, and they can be used 2-3 times in a row.

Disease manifestations: After the top buds or young shoots of seedlings are susceptible, dark green water-stained small spots appear, and then rapidly expand into nearly round or irregularly shaped large lesions, such as scalded by boiling water, and the color gradually changes to gray-green to black-brown. , which occurs in orchards everywhere and is easily mistaken for citrus anthracnose.

The affected branches and leaves are scalded in boiling water and die, and the lesions on them are amorphous, light brown to brown, and the surface of the affected part is balanced and sporangial mold (pathogenic sporangia and sporangia) when wet.

You can use some mercury or leveling solution and brush them on the injured part according to a certain ratio. Or use some carbendazim and methyl tobukin, as well as alkaline water, and dilute and spray according to a certain ratio.

You can use bacterium toxinqing, or fumei arsenic, which is more effective, and you must scrape off the lesions, otherwise it is likely to be **.

The use of 40% fumei arsenic 100-150 times solution for prevention and control, the effect will be better, in addition to other measures.

With 50% carbendazim 300 times solution and 70% methyl tobuzine 500 times solution, the effect is very good.

The disease is severe in young trees or older trees. Especially the newly grafted small trees, extensive management of chestnut orchards, once the outbreak forms a contiguous piece, it will cause great management difficulties to our growers, and the serious ones may destroy the chestnut orchards, causing great losses, Lao Xiaosen is one of the main diseases to deal with in the planting of chestnut trees The temperature rises in the spring of the following year, after the chestnut tree sprouts, the conidia spread with the help of wind and rain, and invade through the wounds of the tree. The disease began to occur from March to April, and the lesions spread rapidly, and after the onset of the thinner branches, the lesions could surround a week in a month, and soon caused the death of the diseased branches or the death of the whole plant.

Rotting bacteria infect chestnut acres, leaves, branches, and fruits. After the leaf is damaged, there will be round or irregularly shaped lesions, which are brown, and in the later stage, there will be small black spots on the edge of the lesions, that is, the conidia disc of the pathogenic bacteria, which is grayish-white. It is a round black lesion and smooth, which sinks and decays after losing water, and is easy to be broken by wind, and will gradually die in the later stage.

The affected buds are brown and rotten.

In this case, spray prevention and control can be used to kill fat emulsifiable concentrate and deltamethrin oil slick, focusing on spraying and preventing the grafting joint and the trunk near the ground; At the same time, the management of chestnut trees should be strengthened to enhance the tree potential and avoid mechanical damage to the tree body. In winter and summer, the trunk is painted white to prevent frost damage and sunburn. The severity of the disease is closely related to the cold resistance of the variety and the strength of the tree. Second, the prevention and control methods:

cultivating cold-resistant varieties; strengthen fertilizer and water management to improve the disease resistance of trees; Scrape off the lesions, and disinfect the wound with 40 times the rotten enemy 50 times or 843** agent stock solution after scraping.

Chestnut fruit has a high sugar content, high yield and the best quality. If the southern chestnut variety is planted in the north, the tree will be weak, drought-tolerant, and susceptible to frost damage. Similarly, the northern chestnut varieties are planted in the high temperature and humidity places in the south, with many pests and diseases, and are easy to grow, not only the fruit quality deteriorates, but the pathogen overwinters on the diseased tissue with mycelium, conidia and ascomycetes, and produces conidia, which are spread by wind and rain and invade from wounds.

The severity of the disease is closely related to the cold resistance of the variety and the strength of the tree.

The first is that the yield of all chestnuts will decline due to the guide beam, and most of the chestnuts will start to deteriorate when they open vertical yards, and the chestnuts will also infect each other's residues, resulting in more chestnuts being affected.

If chestnut is plagued, the disease will infect the leaves, branches and fruits of chestnut. The leaves will appear large and small spots, and they will gradually die in the later stage, resulting in a great decline in the yield of chestnuts, so it is necessary to prevent this disease in time.

Mainly, this disease will cause a wide area of infection, and it will affect the growth of plants, lesions, and the yield of chestnuts.

The causative agent is Cryptobulb Red Shell [cryphonectriaparasitica (murr.).）barr.], which belongs to the phylum Ascomycetes.

The subbase is oblate-conical, often orange-red, millimeters in diameter, with endophytic conidia or ascomycetes. The shape of the conidia is irregular, the size is different, the wall of the inner cavity is densely conidia, the conidia are colorless, solitary, a few are branched, and the conidia are born on the skin. The conidia are colorless, unicellular, cylindrical or oblong-oval, and have a size of 3 to 4 microns.

Ascomycetes brown to black, spherical or oblate spherical, 150 350 μm in diameter, deeply buried in the substellar tissue. There are several to dozens of ascomycetes in 1 sub-base, which are open at the apex of the sub-base. Ascomycetes are club-shaped, colorless, 33 40 microns in size, with thickened parietal walls, pores, and 8 ascospores.

Ascospores are arranged in single rows or irregularly, oval, colorless, with a transverse septum and a constriction at the divider.

1) Implement quarantine. Strict quarantine of chestnut and oak seedlings, scion, bark logs and branches to prevent the introduction of diseases into disease-free areas.

2) Strengthen the tending and management of chestnut forests.

3) Completely remove seriously diseased plants and severely diseased branches, and burn them in time to reduce the infection of pathogens**. For individual lesions on the main stem or branches, first scrape off all the diseased bark with a sharp knife to a depth of xylem (the scraped bark is burned intensively), and then apply 200 times of antibiotics (402), 300 times of 50% carbendazim or 300 500 times of methyl tobuzin.

4) Biological control. In 1965, the attenuated strain of chestnut blight was discovered in Europe, which has almost no pathogenicity to chestnut and can inhibit the growth of toxic fungus dust system. The application of attenuated bacteria in the control of chestnut blight has been tested in Bilu in some areas of Europe and the United States, and good control effects have been obtained.

Chestnut blight, also known as chestnut blight, chestnut rot disease, and chestnut blight, is one of the main diseases of chestnut trees. All the main chestnut producing areas in China have a spit, and the incidence rate is gradually decreasing from north to south. If the disease is mild, the trunk is locally infected, which causes the weakening of the tree and affects the flowering and fruiting. In severe cases, large areas of the trunk of the tree festered, and the whole plant died quickly.

In some areas, the newly grafted small trees are very sick, often occurring in patches, causing the bark to rot and round until the whole tree dies, and the loss is very large.

Chestnut blight mainly affects the main trunk and main branches, and a few also cause disease on the branches. At the beginning of the disease, the branches fade green, and reddish-brown lesions appear on the bark, which then develop into large, irregularly shaped reddish-brown patches, and finally surround the entire trunk and expand up and down. The tissues of the diseased parts are soft and water-stained, and sometimes yellow-brown juice flows out from the diseased parts, tearing the diseased skin, and it can be seen that the internal tissues are reddish-brown water-stained and rotten, with the smell of sake lees.

In the later stage of the disease, the diseased part loses water, shrinks and sinks, and produces small black nodulous particles under the bark, which is the subseat of the pathogen. The apex of the posterior subbase breaks out of the skin, and after rain or in humid conditions, orange-yellow tendril-like spore horns emerge from the subbase. Eventually, the skin dries out and cracks, and a callus is formed around the lesion.

Saplings often develop disease at the base of the trunk, causing the upper part to die, the lower part to produce callus, and gradually germinate a large number of tillers. In the spring of the second year, the old scars**, most of the tillers died; In summer, a large number of slender but not full tillers sprout. After many years of onset, a tumor-like callus forms at the base of the trunk, which eventually leads to the death of the diseased tree.

The main branch or the base of the main branch of a large tree can also be diseased, and the whole branch will be yellowed and die after the disease part is wrapped around the branch for a week, and the dead leaves are not easy to fall off. Diseased trees (branches) generally have late buds before germination, and the leaves are small and yellow after germination, and the leaf margins are scorched and withered when severe; No new shoots are drawn, or the shoots are very short.