How to prevent and control podocarpus leaf blight? What to do if the leaves of podocarpus are dry?

Leaf blight is a disease caused by polychaete spores of Pine and occurs in Pine. It usually starts at the tip of the branch and the leaves. At first, the susceptible leaves are irregular patches of crimson to brick-red, then brown to light brown, and finally grayish-white, with many small black spots on them; When the disease is severe, the entire tip leaf dies, and some even die the whole plant.

Leaf blight is one of the common diseases of P. sinensis in East and Southwest China. According to a survey in Shanghai, China, the incidence rate of podocarpus planted in the nursery is 50%. In 1985, the disease was investigated in Wuhan seedling farm, and the disease rate was as high as 50-60%.

When the disease is severe, the whole plant dries up and dies.

The prevention and control methods of leaf blight mainly include strengthening cultivation management and timely removal of diseased residues and dead branches and leaves to reduce the source of primary infection. During the onset period, it can also be treated with pesticides, sprayed once every 7-10 days, a total of 3-5 sprays.

Strengthen cultivation management, increase the application of organic fertilizer, do not apply nitrogen fertilizer, prevent stagnant water from being too wet, and pay attention to ventilation and light transmission.

In winter, diseased residues, dead branches and leaves are removed, and burned in a concentrated manner to reduce the source of primary infection. Before the onset of the disease, spray 1% Bordeaux solution for protection; During the onset period, 800-1000 times of 50% dyceammonium aqueous solution, or 600-800 times of 75% chlorothalonil wettable powder, or 600-800 times of 30% copper oxychloride can be sprayed alternately. Spray once every 7-10 days, a total of 3-5 sprays.

Podocarpus bonsai is very popular with everyone because of its evergreen and beautiful posture, but in the whole breeding process, there are often various problems, such as the dry leaves of podocarpus, and what should I do if the leaves dry up? The following is an introduction to the causes and solutions of the dry leaves of podocarpus.

1. Lack of light.

Although podocarpus can grow in a shade environment, it can not be placed in the shade for a long time, photosynthesis will be weakened, and the leaves will dry up, so it should be placed in a sunny and ventilated place for maintenance. Move it to the light and let it bask in the sun.

2. Low-temperature frostbite.

It prefers warm environments and is not hardy. If the temperature is not controlled in winter, it will be frostbitten and the leaves will dry up. Podocarpus has a strong negative tolerance, but its cold tolerance is relatively weak, if it is low temperature in winter, podocarpus will be easy and frostbite, and it is necessary to take warm measures.

3. Lack of nutrients.

When the leaves of podocarpus dry up, it may be caused by poor potting soil and lack of nutrients, especially in the peak growing season, which consumes more nutrients. It is best to apply liquid fertilizer, which can be melted into water with an appropriate amount of compound fertilizer and poured into the potting soil.

4. Lack of water or stagnant water.

When podocarpus lacks water, the leaves will also dry up, at this time to check whether the potting soil is too dry, if so, it should be watered immediately, watering should be carried out in the morning or evening when the hand is ready, can not be watered in the hot imitation of the nucleus at noon.

If the potting soil is in water for a long time, the roots of podocarpus will be hypoxic, resulting in the phenomenon of leaf dryness, at this time, if you look at the potting soil and find that the soil is too wet, the cause of leaf dryness is likely to be caused by waterlogging, stop watering and move to a ventilated place.

The leaf death of podocarpus trees is mainly due to the damage caused by two diseases, leaf spot and anthracnose.

Prevention and control methods: spray with 50% methyl tobuzin wettable powder 500 times, if the leaf tip is withered first, it means that the ventilation is not good, the air humidity is too dry, and the sun can not be basked.

Lack of light can also cause the leaves to die, and if you leave it in the shade for a long time, photosynthesis will be weakened, and the leaves will dry up. It should be moved to a sunny place and let it bask in the sun. Low-temperature frostbite is no exception, it prefers warm environments and is not cold-tolerant.

If the temperature is not controlled in winter, it will be frostbitten and the leaves will dry up.

Symptoms: There are oval, elongated light reddish-brown lesions on the leaves, surrounded by a green ring, which then expands into irregular large patches, and produces black spots on the lesions.

Prevention and control methods: remove diseased leaves in time and spray pesticides in time. It can be sprayed with 500 times of 50% Tobuzin wettable powder.

Symptoms: small brown patches appear on the leaves at the beginning of the disease, and then expand into round or oval shapes. The lesions gradually dry up, and in severe cases, the whole plant is infestation.

Prevention and control methods: First of all, open windows for ventilation to reduce indoor air depression and humidity. Then spray with 1000 times of 70% thiophanate-methyl wettable powder, or spray 70% methyl tobuzin 60% anthrax fome, multibacteria, etc., to prevent the disease from continuing to spread.

Symptoms: Podocarpus is harmed by red spiders, the leaves fade, the chlorophyll is damaged, and dense small yellow spots and small yellow spots appear on the surface, and gradually shrink, yellow, wither, and fall off in severe cases, losing its due ornamental value.

Prevention and control methods: Spider mites often hide on the back of branches, leaves or dense places, pull the net to hide, and it is easier to catch manually.

If it is treated with chemical agents, it can be sprayed with 20% trichlorodiol emulsion, adding 800-1000 times of water to make a solution, and this drug has a good killing effect on adults, nymphs and eggs. It can also be sprayed with 50% dichlorvos emulsion by adding 1000-1500 times of water to make a solution.

Disease manifestations: The harm is very widespread, sucking the sap of stems and leaves, resulting in poor plant growth, and even inducing coal stain disease, resulting in large-scale damage to leaves. It has an earlier prevalence than spider mites and often breeds in large numbers in early spring.

Prevention and control method: When the number is small, it can be removed with a brush. In addition, it can also be sprayed with 800-1000 times the liquid of rapid culling. Mixing a certain amount of carbofuran in culture soil has a preventive effect, but the effect is only 3 months.

Leaf blight is the most headache problem for many flower farmers, the disease mainly occurs on the young leaves of the branches of the podocarpus, after infection, the leaf color is red, the lesions are irregular, from the tip of the leaf to the base of the leaf, resulting in the death of the tip of the leaf. The lesions are light brown in the later stages. With the development of the disease, small black spots were produced on both sides of the diseased part of the leaves in the later stage, which seriously affected the growth and ornamentation of podocarpus.

The disease overwinters in dead branches and leaves with mycelium, and in the spring of the following year, the germs invade young leaves or through wounds into branches. Generally speaking, over-intensive cultivation, poor ventilation, extensive management, and wounds caused by sunburn can all contribute to the onset of the disease, which is more likely to occur in April, May and August, and September.

Control methods: In winter, pruning dead branches and seriously diseased leaves and removing diseased leaves on the surface are destroyed in a centralized manner, and maintenance management is strengthened, which can enhance the disease resistance of plants. In the early stage of the disease, it is sprayed with fungicides such as 1000 times of ammonium desen, 500 times of 75% chlorothalonil, and 100 times Bordeaux of the same amount, sprayed once every 7 10 days, and sprayed 2 3 times in a row to prevent the onset of the disease.

In fact, children are like this, you say that is not the case, I hope it will help you.

There are mainly leaf spot and anthracnose hazards, sprayed with 50% methyl tobuzin wettable powder 500 times, the situation you said is relatively simple, if the leaf tip is withered first, it means that the ventilation is not good, the air humidity is too dry, and it can not bask in the sun, it needs semi-shade maintenance, watering should be watered thoroughly at one time, and it will be watered when it is dry.