How to prevent and control watermelon white silk disease, how to prevent and control watermelon powd

Prevention and control methods: Strengthen plant quarantine, select disease-free seedlings, or dip and disinfect with 20% lime water below the base of the stem before transplanting, and try to avoid opening up new tea gardens on crops that are susceptible to the disease; Strengthen management, improve soil, increase organic fertilizer, promote the healthy growth of tea seedlings, and improve disease resistance; Soil treatment before planting, soil pesticide application or removal of diseased plants during the onset period, copper sulfate solution and 50% carbendazim 500 600 times (80 100 grams per mu) were sprayed in the diseased holes, and 98% cotton granules were mixed with 1 2 kg per mu mixed with fine soil ditch.

Powdery mildew is a serious disease that occurs all over the country, regardless of whether it is cultivated in the open field or in the open field, it will occur throughout the growth period, commonly known as white hair disease and powder mold. It mostly occurs at the fruiting stage and ripening stage. Once a disease occurs, it develops rapidly.

If it is not prevented in time, it will lead to scorched yellow melon leaves, premature aging of plants, and melons will turn into melons.

1) Symptoms This disease mainly infects leaves, petioles and vines, and the underside of the leaves and fruits suffer less damage. Small round white powdery mold spots grow on the front or back of the leaves, and soon gradually expand or larger white powdery mold spots, and in severe cases, the whole plant is covered with a white powdery mold layer.

2) Pathogenesis The pathogen is Powdery mildew monofilament. Germs spread through the air. The appropriate temperature of the disease is 15 28, when the conidia are above 30 or below 1, they quickly lose their vitality, and the air humidity is not strict, and the onset humidity of 45% and 75% can occur, and 80% and 90% are the most suitable.

Plants that are too dense, poorly ventilated, over-applied nitrogen fertilizer, and poor plant growth are all prone to disease. When the cultivated area is cultivated at high temperature and poor ventilation, the lower old leaves are seriously diseased. Open field cultivation is popular in summer and autumn when it is dry, cloudy, sunny and rainy.

Too much nitrogen fertilizer, or weak growth, severe disease.

3) Prevention and control methods should strengthen field management, timely pruning and pruning, appropriate application of phosphorus and potassium fertilizers, timely removal of diseased leaves and plants, and strengthening ventilation and light transmission.

The protected area can be smoked with 45% chlorothalonil aerosol.

More than 10% 100% dust agent is sprayed, using 1 kg per 667 m2 in the evening.

20% Fuxing 8000 times liquid spray.

5% Rust 2000 times liquid spray.

The above agent is sprayed 1 time in 7 10 days, and sprayed 2 3 times in a row.

Reasonable dense planting, adopt high furrow and deep furrow planting method. furrow covered with mulch; Focus on strengthening field management after the melon period, reasonable pruning, and timely removal of seriously ill leaves and some old leaves, so as to facilitate ventilation and light transmission, reduce field humidity, and reduce the repeated infection of pathogens.

Grasp the characteristics of watermelon that loves water and is afraid of water, and adopts a dry, dry and wet irrigation method; Pay attention to drainage after rain to prevent flooding and water staining in the melon field; After continuous rainfall, pesticides should be applied as soon as possible to prevent the rapid spread of the disease in melon fields.

Do a good job of fertilization. Organic fertilizer is the main method, organic fertilizer and inorganic fertilizer are combined, and nitrogen, phosphorus and potassium are combined. In the later stage of watermelon, compound fertilizer should be the main fertilizer, and urea should be applied as little or no as possible to improve the disease resistance of the plant.

Strengthen cultivation management, pay attention to the combined application of nitrogen, phosphorus and potassium fertilizers, and prevent partial application of nitrogen fertilizers. Cultivating robust plants. Pay attention to plant adjustment in time to prevent the leaves and vines from being too dense and affecting ventilation and light transmission. Cut off the diseased leaves in time and burn them to prevent the spread.

Watermelon powdery mildew is a headache, how to prevent and control it, increase knowledge!

Watermelon powdery mildew is a headache, how to prevent and control it, increase knowledge!

Watermelon powdery mildew, commonly known as "white hair". Caused by infection by pathogenic fungi of Ascomycetes subphylum Monofilament Shell or Powdery Mildew. It is prone to occur in areas where watermelons are grown all year round.

In the seedling stage, it affects the development, and can cause the plant to die in severe cases; Generally, the damage is heavier in the middle and late stages, which makes the plant senescent prematurely and affects the yield.

First, the incidence of the disease.

It mainly overwinters with mycelium and conidia on diseased residues or weeds, and the pathogens are mainly spread by air flow and other means in the coming year. After the disease of watermelon, it produces spores, which are spread by wind and rain, causing re-infection. The disease is more serious when the humidity is high in the field and the temperature is 15-25.

2. Pathology and identification.

Powdery mildew mainly occurs on leaves, but stems and petioles can also be affected. At the beginning of the disease, small round white spots appear on the leaves, which gradually expand into white pink spots. When the lesions are connected into patches, the leaves and stems are covered with white powder, and after a while, the white powder becomes grayish-white, and small brown or black spots are sometimes visible on it; The leaves are withered and curled and do not fall off easily.

3. Prevention and control methods.

1. Agricultural prevention and control. soil disinfection and crop rotation; Strengthen cultivation management, reasonably increase phosphorus and potassium fertilizers, and improve the resistance of plants; Strengthen field management, remove diseased leaves in a timely manner, and burn them in a centralized manner to prevent the spread of pathogens.

2. Chemical control. In the early stage of the disease, 25% powder-rust 2000 times liquid, or 70% methyl tobuzine wettable powder 800-1000 times liquid, or 35% ruixin copper 500 times liquid, etc., the effect is significant.

Hello? For your reference: you can use 5000 times ditambuconazole solution for prevention and control. It is enough to carry out re-prevention and treatment at an interval of 7 to 10 days.

Thank you for your question.

Use Shigao (difenoconazole) or ethylpyriphenol or chlorite.

Watermelon powdery mildew is a headache, how to prevent and control it, increase knowledge!