Traditional Culture Encyclopedia - Weather forecast - In hot and rainy summer, vegetables appear yellow leaves, long spots and rolled leaves. How to prevent it?

In hot and rainy summer, vegetables appear yellow leaves, long spots and rolled leaves. How to prevent it?

In hot and rainy summer, vegetables appear yellow leaves, long spots and rolled leaves. How to prevent it? In hot and rainy weather in summer, vegetables grown at home are particularly prone to yellow leaves, leaf spot and leaf curl, especially tomatoes, peppers, cucumbers, pumpkins and loofahs. It is serious every year, and some even get out of control. Once vegetables occur, if they are not prevented in time, they will spread rapidly in the whole factory in a short time. Even if they occur in a large area, it is difficult to recover even by the best method. Therefore, we should not take it lightly.

1, there are many reasons for yellow leaves in yellow leafy vegetables, such as hard soil, lack of nutrients, excessive irrigation, soil drought, root system hypoplasia, pests and diseases, etc. All these will cause the yellow leaves to defoliate and its growth will be poor. Therefore, from planting to management methods, we must ensure proper watering and topdressing. The key is to raise the roots well, create a suitable growth environment for the roots, and ensure that the roots have enough strength to absorb nutrients and water, so as to promote the vigorous growth of branches and leaves and prevent the production of yellow leaves.

When planting and transplanting vegetables, base fertilizer must be fully applied, generally using organic fertilizer, less using organic fertilizer. For hard soil and soil with serious diseases, in addition to adding organic fertilizer, adding microbial fertilizer properly, or using biological agents and multifunctional rooting fertilizer to irrigate roots, will receive excellent results.

In terms of supervision, the soil should not be too dry or too wet. Sprinkle water according to the temperature, soil drought and vegetable growth, and keep the soil dry and wet. If the bottom blade turns yellow, it should be removed in time to improve ventilation and sunshine. The yellow leaves caused by diseases can be sprayed by root irrigation with 50% thiophanate WP 500 times solution or 500% carbendazim suspension 500 times solution.

2. The leaf spot disease of long-spotted vegetables has been puzzling many growers, but there are many kinds of leaf spot diseases, such as brown spot disease, brown spot disease and macular disease. The disease not only damages leaves, but also seriously harms leaves, stems and fruits. However, no matter what kind of leaf spot disease it is, early detection and prevention, timely removal of diseased leaves, cutting off the source of infection, preventing other plants with physical and mental health from being infected, and timely selection of corresponding therapeutic drugs and methods for spraying can achieve good practical results.

Leaf spot disease is generally more serious in the natural environment with high temperature and high air relative humidity, and it is less serious in the dry climate. How to prevent and control it?

No matter what vegetables are planted, rotation planting and stubble planting should be carried out instead of planting one crop. If long spots and yellow leaves are found, they should be collected in time to prevent the spread of pathogens. When diseases are found, 50% carbendazim wettable powder 1500 times solution, 8% tribenuron-methyl 800- 1000 times solution, 50% thiophanate 1000 times solution and 50% captan 500 times solution are sprayed on the leaves in time. According to the degree of illness, spray once every 5-7 days until the illness is under control.

Vegetables like to use pesticides, and the only way is to spray the mixture of sugar and cold every 7- 10 days during the whole growth period of vegetables. The method is to add 50 grams of anhydrous glucose, 30 grams of urea solution and 20 grams of white vinegar to 30 kilograms of water, and spray the front and back of the leaves after stirring evenly, which can also reduce the occurrence of brown spots.

3. Leaf-rolling vegetables are divided into physiological leaf-rolling and leaf-rolling caused by diseases and insect pests. The root cause of physiological leaf curling is mainly caused by dry and wet soil, high temperature, unreasonable fertilization, excessive watering, fertilizer damage and incomplete root development. The other is leaf curl caused by various diseases and insect pests.

The temperature is high in summer, and the water in leaves evaporates quickly. When watering, remember to water it in the morning, not in the afternoon, but in the afternoon. Pay attention to the distance between chemical fertilizer and root system when fertilizing. Not suitable for too close, alcohol-free, high-concentration organic fertilizer. On the premise of effectively providing liquid fertilizer, spraying brassin mixed with amino acid foliar fertilizer on the leaves can regulate the growth of leaves and restore the growth charm.

After all, the root system of leaf roll is not developed. In the case of poor growth of branches and leaves and hard soil, humic acid, alginic acid, biological agents and other fertilizers with rooting and root-raising effects can be used for root irrigation to promote root development and naturally flourish leaves. Leaf curling caused by pests and diseases should be found in time, and relevant pesticides or fungicides should be used to prevent and control it in time.