It is found that there are many macules in young leaves, how to treat and prevent them?

There are always yellow spots on the leaves of seedlings, which look particularly unsightly, and it is likely that rust is at work! Rust is a fungal plant disease that is most likely to occur during the rainy and windy seasons in spring and summer. In addition to affecting the landscape effect, rust can also cause symptoms such as tumors, rough bark, clump branches, and curved branches on the branches, or cause leaf fall, scorched shoots, poor growth, etc., and in severe cases, the plants will also die quickly due to the evaporation of a large amount of water in the body.

1. Symptoms.

Rust mainly affects leaves, but can also damage green tissues such as fruits, petioles, fruit stalks and new shoots.

1. Leaf disease.

At the beginning of the disease, small oily orange-red spots appear on the front of the leaves, which gradually expand to form round orange-yellow lesions with red edges. In severe disease, dozens of lesions appear on a single leaf.

2. Petiole disease.

The lesion is orange-yellow, slightly raised, mostly spindle-shaped, with small punctate spore organs on the surface at the initial stage, and brush-like rust spore cavities on the back of the lesion in the later stage.

3. Onset of new shoots.

At first, it is similar to petiole damage, but in the later stage, the diseased part is sunken, cracked, and easily broken. The horns of winter spores are dark brown, undulating in the shape of a cockscomb, and when it rains, it absorbs water and swells, and is gelatinous petal-shaped.

4. Fruit. After the onset of the disease, the young fruit mostly forms lesions with a diameter of about 1 cm near the calyx depression, which is orange-yellow in the early stage and black in the later stage, and produces sexual spore organs in the middle, and hairy rust spore organs grow around it. The growth of diseased fruits is stagnant, and the diseased parts are hard, mostly deformed, and often fall off in advance.

Second, the incidence of the disease.

The pathogen is a metaparasitic rust fungus, which forms a winter spore pile on the cypress and juniper, and the bacterium has no summer spores, so it can no longer be infected, and it is only infected once a year. The stage of sexual sporozoite and rust sporophyte parasitizes on plants such as pear, begonia, begonia, papaya, etc. The pathogen overwinters in the diseased tissues such as cypress and juniper with mycelium, and the mycelium of the following year overwinters in early spring to produce winter spore angles, and the winter spores germinate to produce basidiospores, which are spread to the leaves of begonias, pears and other plants by air currents to infect the damage, 10 14 days of foliar spore formation, about 28 days of rust spore on the back of the leaves, and June is the peak period of the disease.

8 In September, the rust spores are propagated by the air flow to the cypress and juniper, infecting the needles and twigs and overwintering, and the disease is severe in early spring when it is warm and rainy.

3. Comprehensive prevention and control.

1. Prevention and control together.

For the side of the highway, we can't cut down the juniper cypress in the nursery, so we can spray the juniper and fruit trees at the same time, so that the juniper and fruit trees can be exempted from harm at the same time, so as to achieve unified medication and group prevention and treatment.

2. Remove diseased buds in early spring.

Care must be taken to avoid scattering the spores during operation, otherwise the desired effect will not be achieved.

3. Breeding strains with strong disease resistance seedlings or afforestation.

It is advisable to choose varieties with strong disease resistance and varieties suitable for local planting, and the occurrence of rust will be alleviated to a certain extent in the same external environment.

3. Pharmaceutical prevention and control.

After the rust is found, it is necessary to spray pesticides in time to prevent and control it, the sooner the better, there are many pesticides available on the market at present, and they are usedManchi (difenoconazole) + medium liter buzin (thiophanate-methyl) + Arcadian seaweed fertilizer.

The young leaves have yellow spots, indicating that there are small insects on the leaves, at this time we must take medicine in time, after a long time, the leaves will wither, and it will be too late to remedy it at this time.

This may be due to insect infestation, and we need to clean these young leaves with yellow spots and spray them with pesticides. Usually we had better let it have adequate ventilation and light.

There are several main reasons why there are yellow spots on the leaves.

The first reason is that diseases such as yellow spot, leaf spot, leaf blight, etc., can cause yellow spots on the leaf surface, which in turn will cause the leaves to turn yellow.

The second reason is that the foliar surface is sunburned and macula is formed in the summer.

The third reason is the uncomfortable temperature, the appearance of macular at low temperatures.

The fourth reason is that water and fertilizer are not applied properly, which affects the growth of roots and has yellow spots on the leaf surface.

The role of leaves:

The leaves of some trees can be used as pesticides, for example, ginkgo biloba leaves contain benzylic acid, glutinol, mashed and soaked juice spray, can control aphids, cabbage worms, poisonous moths, cicadas and other pests.

The sun-dried and ground powder of ginkgo biloba leaves can be applied to the soil, which can effectively control grubs, ground tigers, needleworms, etc. The leaves of peach trees, arborvitae and elm trees can also be used as pesticides, soaked juice spray or sun-dried grinding powder and applied to the soil, which has the advantages of high efficacy, low cost, no harm to natural enemies of pests and no pollution of the environment.

The leaf tea made from sour jujube leaves has diuretic, promoting bile acid synthesis and anti-inflammatory effects. Hawthorn leaves can be made into a hawthorn ketone juice drink. In addition, persimmon leaves, willow leaves, arborvitae leaves, and bamboo leaves can all be drunk instead of tea.

Improper watering: Fortune likes to grow in a humid environment, and needs to be watered in time, otherwise the leaves will be dehydrated, resulting in the loss of color of the leaves, macular and other adverse symptoms, and can not be watered too much, otherwise it will accumulate water and rot the roots, so that the head of the fortune can not absorb the nutrients in the soil normally, and will also make the leaves appear yellow spots, reducing the ornamental value of the head of the fortune.

If you find that the head of Hongyun is overwatered, the leaves have yellow spots, you need to cut off the rotten roots, replant them in the new soil, and put them in the sun to breed normally, generally in spring and autumn you can water every 3 7 days, once a day in summer, and every 10 15 days in winter.

Precautions for the maintenance of good luck.

Fortune needs to be raised in slightly acidic soil with rich humus, high nutrient content, good drainage and air permeability. Generally speaking, you can directly purchase special culture soil, but if you want to configure it yourself, it is recommended to mix it with river humus and river sand, and add a small amount of cake fertilizer or rotting chicken manure.

Hongyun Dangtou prefers a relatively humid growing environment, and the soil moisture is best at 70%-80%. Usually pay attention to the dry and wet condition of the soil, and replenish water as soon as it starts to dry.

To solve the macular problem of goldfish spider plant, it is good to do a few points every year.

1. Infected with downy mildew.

When cucumbers are infected with mildew, there will be gray-brown mold on the front and back of the leaves, and gradually start to turn green, and the leaves will slowly turn yellow. The back of the leaf will have a black mold layer. This disease is mostly caused by improper management.

At the beginning of the disease, it is necessary to spray the medicine in time to treat it, and guess that the diseased part will be removed to avoid further infection. In addition, it is necessary to change the maintenance environment, usually ventilate more often, and provide a suitable environment for growth, so that it is possible to recover slowly and avoid further disease.

Second, it is caused by direct blowing of cold wind.

Cucumbers like to grow in relatively warm places, and are not resistant to wind, especially cold winds, otherwise the leaves are easy to lose green after a long time, and yellow spots and white spots will slowly form. Pay attention to the wind when giving it from small to large, not in a hurry, to avoid direct blowing of cold wind. As long as the management is strengthened in the later stage, the plants can still recover slowly.

3. Hypothermia frostbite.

Cucumbers have limited cold tolerance and prefer warm environments. If the temperature provided for a long time during the maintenance period is below 0 degrees, it is easy to frostbite the plant. There are yellowish-white spots on the leaves, and they will even die slowly, and the growth rate will become very slow, and the plant will not be able to continue to take root and grow.

It is necessary to find the cause of low temperature as soon as possible, and take warm measures in time. It is best to maintain the temperature between 25 and 30 degrees Celsius during the day and above 10 degrees Celsius at night so that it can grow vigorously.

Overwatering, spraying carbendazim.

First, the yellowing of the leaves of the round leaf pepper is usually caused by watering too wet leaves yellowing, because too much watering is easy to cause potting soil water accumulation to cause root rot and leaf color yellowing, drooping and other symptoms, it is best to properly loosen the pot soil is conducive to water drainage to reduce the yellowing of leaves, conducive to the normal growth of the root system, usually do watering after drying, there is a sense of dampness dripping water is not watered.

Second, the lack of water in the pot caused by long-term watering or unloosened potting soil leads to leaf loss of water and yellowing, and the appropriate loose potting soil is conducive to watering potting soil moisture absorption, which is conducive to the normal water absorption of the root system and reduces the symptoms of leaf yellowing caused by lack of water.

3. Long-term indoor shady place is not conducive to the yellow leaf symptoms produced by its photosynthesis, usually placed in the indoor sunny ventilation place to reduce the yellow leaf phenomenon caused by growth or insects.

Fourth, the yellow leaf phenomenon caused by excessive fertilization or insufficient nutrients, because the lack of nutrients in the pot is easy to cause the leaves to turn yellow, you can apply the water-soluble fertilizer of Ribery Yanwo to the side of the pot according to the amount, but the amount of fertilizer should not be too much to prevent the symptoms of yellowing of the leaves caused by the burning of the roots produced by fertilizer.

Fifth, in summer, it is necessary to prevent exposure to the sun to prevent the leaves from being scorched, and the outdoor ones can be shaded, and in the winter to prevent the yellowing of the leaves caused by frost damage, and can be moved indoors to the sun to facilitate its safe winter.

When the yellowing of the leaves is more severe, the more serious yellow leaves can be cut off to reduce the symptoms of the yellow leaves, and the whole plant can be sprayed with 1000 times of carbendazim or tobuzine to achieve the effect of disease prevention.