Can t prevent melons from dying seedlings? How to find out the cause of dead seedlings?

Dead melon seedlings are a common melon disease that is named after it has been discarded. The disease spreads throughout the country, especially in the watermelon-producing areas of the Yangtze River Delta. In addition to harming watermelon, the disease damages cantaloupe, pumpkin, cucumber, etc., often causing early death and causing production.

The main symptoms. The leaves are damaged, initially appearing black-brown spots, which are 1 to 2 cm in diameter. The spots are round or irregularly rounded, dark brown or with concentric bands.

Lesions occur on the leaves and are usually curved. Small black dots appear on the old dots. When it comes to the case, the lesions are stars and stars.

Persistent rainy weather, the rapid development of spots can spread all over the leaves, the blades are black and dead.

Symptoms of leaf disease.

Causes coronary disease, produces a grayish-white oval shape in the vicinity, and spots are born on neutral black spots.

The fruit is stained, producing water stains, ** the center changes to a brown dead zone, and there are star-shaped cracks, and the inner bundles are dry and corroded, slightly black.

Cause of disease. Bacillus flats, Bacillus bacillus, Azton fungus. Spore spore balls are formed as flat bulbs, dark brown, the top is purely protruding, and the holes are distinct.

The spores are short, round, cylindrical, colorless and transparent, with both ends, primary cells, which then give rise to 1 to 2 membranes, slightly reduced. Neck-burped or spherical, dark brown. Cospores are short or spores, colorless transparent and one separated.

Onset. Watermelon hexylin attaches to pain in the blood circle pain and the size pain of the pathogen. When next year's temperature is right, the humidity is suitable, scattered spores, fluid blowing, rain splash damage.

Surface surfaces can also be used. The pathogenesis mainly invades the internal watermelon plant.

Cause. The relationship between this disease is closely detrimental to temperature, humidity and culture management techniques. In the range of 10°C -34°C, the waiting time of the pathogen is reduced by temperature, and the relative humidity of the air is greater than 80.

Connections, low terrain, weak water, water, loss or growth, fast conditions; Over-transplanting, poor ventilation, too high humidity.

Prevention and**.

1.Selection of disease-resistant varieties: suitable cultivars can be selected according to different cultivation seasons.

2.Drug treatment: Before sowing, mix 3-Phenyl Ether-Necronymia suspension dressing, and 3-Phenyl Ether-Cycloazole suspension can be grown. It can effectively control the occurrence of grapevines.

3. The plot of planting watermelon should be practiced using melon crops 2-3 years old; Fertilization of basal fertilizers, ubus amounts, especially cakes, phosphorus and potassium cooperatives; Blocks are planted. After the rain, the case will be removed in time. After harvesting, it thoroughly cleans up bleeding and grinding weeds, concentrating deeply or burning to reduce disease**.

In addition, it can effectively reduce the possibility of germ infection, while reducing humidity and reducing or preventing disease. 4.The drug begins or initial hair during the disease, butylpyridyl acid suspension 40-50 ml, or 40-50 ml mu, or 40 phenol pyraclosthen ester suspension 20-25 ml mu, more 30 kg of water, sprayed 1 time for 7-10 days, or even sprayed 2-3 times, can better control the occurrence of watermelon.

Can't prevent it. One is physiological wilting, and the other is the appearance of disease.

After the grafted melon seedlings are planted in the greenhouse, when there are more cloudy days, foggy days, rain and snow days, the growth of melon seedlings is weak due to weak light and low temperature, and the number of roots is small. Improper management of fertilizer and water, due to the good airtightness of the greenhouse itself, the humidity is not easy to lose, if the irrigation amount is large or long-term soaking interface, it causes soil-borne disease infection, or causes root suffocation, produces toxic substances under anaerobic conditions, makes the roots poisoned and wilted, or applies unrotted organic fertilizer or one-time topdressing fertilizer too much to cause root burning, weak root activity, reduced fertility resistance, and causes fertilizer damage, loss of root absorption ability leads to the death of melon seedlings.

Dead melon seedlings are a common problem, but finding out the cause can reduce losses.

Among them, the reasons for the death of melon seedlings are: 1. Poor disease resistance of varieties. 2. Climatic factors. 3. Improper fertilizer ratio. 4. Spraying to prevent diseases is not scientific.

The reasons for the death of melon seedlings are: 1. Too much water, and the seedlings are rooted. Roots mostly occur in long-term low temperature, high humidity, and low light weather, resulting in drooping of seedling cotyledons, turning from green to yellow, and root rotting resulting in wilting and death of aboveground parts.

2. The root system of seedlings is relatively sensitive, and unrotted organic fertilizers, especially chicken manure, will cause crops to burn their roots; Damage to crop roots due to the application of adulterated fertilizers; Excessive application of fertilizers leads to excessive soil fertility, which can harm crop roots. 3. The temperature suitable for the root system of melon is mainly 15 20, and the temperature is too low to cause the root system of melon seedlings to be relatively weak and easy to die.

Solution: Sterilize the seeds before sowing. Soak the seeds, soak the seeds with 70% methyl tobuzine 500 times solution or 50% carbendazim wettable powder 1000 times solution for 40 minutes, rinse with water after removal, promote germination, and sow seeds.

Seed dressing, dry seed sowing, soak the seeds with water and then take them out, mix the seeds with 70% methyl tobuzin or 50% carbendazim powder by weight of the seeds, and then sow the seeds.

1. Physiological wilting, no bacterial pus in the middle of the stalks. This is usually caused by a problem with the root system. For example, when watering, too much water is used, the soil moisture is high, the root growth is poor, and the growth of the plant is affected and wilts.

In order to avoid such problems, when watering, try to water as little as possible, and also pay attention to the watering time at low temperatures. When watering, you can add some root protection, such as potassium fulvic acid, chitin, etc., to protect the root system from damage, so that the plant can grow normally. 2. Diseases occur, causing plants to wilt, both fungal and bacterial diseases.

For example, melons wilt and wilt at the swelling stage, and the plant turns from green to yellow in about 7 to 10 days, and the whole plant dies. It takes about 3 to 4 days for bacterial wilt and dies in the case of green leaves. For this disease, it is necessary to dip the roots when transplanting.

In addition, after sitting on the melon, you can irrigate the roots in advance to prevent it. Commonly used dichlorfen, allicin, fludioxonil, copper preparations, etc. to irrigate the roots, each plant needs about 60 ml. In order to improve the effect, you can change the recipe and then irrigate the roots after an interval of one week.

Climatic reasons. After the grafted melon seedlings are planted in the greenhouse, when there are more cloudy days, foggy days, rain and snow days, the growth of melon seedlings is weak due to weak light and low temperature, and the number of roots is small.

Dear, I will find out for you: the reasons for the death of seedlings during the ripening period of melons are as follows: the reasons for the death of seedlings when melons are ripe: 1. Melon wilt. The onset of melon wilt is very rapid, and it can cause the plant to wither and die in 3-4 days.

At the beginning of the disease, the melon wilted at noon and returned to normal in the morning and evening. After that, the leaves dry up severely, and the melon plants grow quickly. 2. Melon wilt.

Melon wilt is most severe in warm chamber greenhouses and can occur throughout the growing period of melons. In the flowering and fruiting stage, especially when the disease occurs in the late stage of fruit ripening, it can lead to the destruction of seedlings in the entire greenhouse.

1.Physiological wilting: when the light is strong and the temperature is high, the leaves of the melon seedlings wilt, and return to normal in the evening and morning, the root system grows well, there are no rot symptoms and root-knot nematode root nodule symptoms, the stem grows well without cracked vine gelatin, the stem and vine cross-section is sterile, and there is no browning lesion in the xylem.

2.Pathological wilting: In the early stage of the onset of Fusarium wilt, the main manifestation is that the leaves of the whole melon plant wilt during the day, and return to normal at night, and the plant will no longer recover at night as the disease develops, resulting in plant death.

When the plant is pulled up, the root epidermis is rotten, the xylem is browned, and the root hairs die. The initial characteristics of vine blight are not obvious, the baloem at the base of the stem is cracked or rectangular gray-white lesions are formed, and when the melon is watered, due to the increase of humidity, the epidermis of the stem base is cracked, and the xylem is browned. If it is mixed with bacterial infection, it will rot and have an unpleasant odor.

The first is that you may add a lot of fertilizer to it in order to mass production, resulting in its nutrient absorption will burn the roots, it will easily lead to wilting, you must go to its fertilizer in planting and then water it, so that it can be absorbed very evenly.

It may be because of physiology, it will return to normal without worry, or it may be because of pathology. It may be because the soil is moistened by watering too much.

Melon blight, easy to cause dead seedlings.

Agricultural control: choose well-drained and high-dry plots for planting.

Lime was applied to adjust the pH of the soil, so that the pH of the planting field was slightly alkaline, and the amount of quicklime was 50 100 kg per mu.

Do a good job of thermal insulation at the seedling stage to prevent low temperature and cold wind invasion, watering should be determined according to soil moisture and temperature, strictly prevent excessive humidity, and the watering time should be changed in the morning.

Seed treatment: Seed treatment is carried out before sowing, and 45% of the seed weight of the seed can be adhered to the seed surface, and then a small amount of fine soil is mixed before sowing. It is also possible to wet the seeds with 75% Weifu wettable powder or 40% double wettable powder for seed dressing, or 50% Likella wettable powder or 70% soil fungus wettable powder after the seeds are wetted.

Chemical control: conditional application of antibiotic fertilizer, application of compost made of enzyme bacteria or decomposed organic fertilizer.

180 360 grams of 95% sodium disulfonate wettable liquid, 150 220 grams of 20% methyl phosphorus emulsifiable concentrate (one clear), 5000 grams of 40% pentachloronitrobenzene (soil bacteria), 1000 1500 grams of 20% copper acetate (soil mycium). In the early stage of the disease, 30% phenylthiocyanide (multibiotic) emulsifiable concentrate, 50ml per mu, 5okg of water, diluted into 1000 times liquid spray, can effectively prevent and control cataplexy and blight, and also treat anthracnose and wilt at the seedling stage. In addition, it can also be sprayed with 72% manganese-zinc * frost urea (Kelu) wettable powder 600 times liquid, vanzitong * mancozeb (Yibao) water dispersible granules 1500 times liquid, 60% fluoromorph* manganese zinc (fenke) wettable powder 700 times liquid, 30% oxamine (soil fungus elimination) water solution 800 times liquid, each Jinggangmycin water solution 1000 times liquid, or 45% Tekeduo suspension 1000 times liquid, or 50% promethexin wettable powder 1000 times liquid, Pulik water solution 800 times liquid.

The application of transplanting mixture has strong bactericidal power, and at the same time, it can promote the resistance of the root system to unfavorable climatic conditions, and can prevent the occurrence and spread of blight.

In areas or fields with severe fruit rot disease, the melons should be padded and sprayed with 30% emulsifiable concentrate 1000 times or Yunda 120 (brassinolide) plant growth regulator 3000 times if necessary.