Downy mildew is also called fire dragon, crawling horse. It is the main disease on many vegetables. Due to its rapid development and serious harm, it has become a key disease for farmers. Downy mildew mainly affects the leaves, which develop from the base to the upper part of the blade, which can cause a large number of leaves to dry up, resulting in reduced production. The following series of Huinong.com and the growers talk about the main symptoms and prevention methods of downy mildew.
First, the main symptoms
1. Cucumber downy mildew symptoms
2. Cabbage downy mildew symptoms
3. Spinach downy mildew symptoms
4. Cucumber downy mildew field damage
Second, the cause of the disease and the route of transmission
The pathogen is overwintered by the hyphae on the seeds or on the autumn and winter lettuce, and the oospores can be overwintered on the sick body. It is mainly transmitted by airflow. The spore germination temperature of the pathogen is 6～10°C, and the suitable infestation temperature is 15～17°C. The planting in the field is too dense, the watering is too early after planting, the water is too large, the soil moisture is high, and the drainage is easy. Continuous rainy weather in spring or early summer is most likely to occur, and when the disease is serious, it can cause 20% to 40% of yield loss.
Third, prevention and treatment methods
Downy mildew is caused by rapid spread and serious harm. Once it is introduced, it is difficult to eradicate. Therefore, prevention and control of downy mildew must be based on prevention and prevention.
1. Selection of resistant varieties: Variety of disease resistance can greatly reduce the harm of downy mildew. Therefore, in the prevention and treatment of downy mildew, we must first consider the selection of resistant varieties.
2, watering: for vegetables susceptible to downy mildew, can be used in the seedling bed planting with 72.2% frost mold water 500 times liquid watering the seedbed, the effective period of up to 30-50 days, basically can guarantee that the seedling period will not infect frost mildew.
3. Irrigation root: When the vegetables are planted, the roots can be irrigated with 72.2% of the mildew water-repellent agent 400-500 times, and the downy mildew can be prevented before the flowering and fruit setting. The effective period can also be more than 50 days.
The above are the main symptoms and prevention methods of downy mildew in vegetable planting compiled by Huinong. As the weather changes, vegetable growers should take care of their own vegetables to prevent them.
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