Control methods of Potato late Blight

Potato late blight is a kind of harm caused by Phytophthora, and this disease harms potatoes more seriously, so today we will separately talk about the origin, infection process and symptoms of potato late blight disease. and when to control, prevention methods of the relevant content, to help you understand the late blight.

Symptoms of the disease

The leaves are susceptible, with a water immersion and a green halo surrounding the plaque, which expands rapidly and turns brown after rain, and the sporangium grows rapidly on the back of the leaf, which looks like a white mildew. When the weather clears up, the damaged leaves will dry up and crack easily. After infecting stems and leaves, brown spots occur and spread to leaves in the later stage, when the symptoms are different, generally showing black rot and withering. Underground tuber disease, Mr. brown spot, rot, depression, expansion, full rot.

II. Disease infection

The pathogen is a kind of pathogenic Phytophthora, which mainly produces conidia transmission harm. Swimming spores can be produced in water, generally zoospores can directly penetrate parasites, the speed of transmission is very fast, transmission conditions are very good, easy to infect. Soil moisture, Rain Water and irrigation water can all be infectious vectors. And since the temperature rebounded in spring, the growth and germination was particularly rapid. Warm and humid is the main disease of high temperature, from late spring to summer is the high incidence of bees.

Third, the inducement of the disease

It is cloudy and rainy in spring, high soil moisture, high temperature in summer, a lot of rainfall, much water in the field and large water mobility. The temperature is high at night in summer, and the temperature does not drop, which is suitable for the growth of bacteria. The humidity of the air continues to be too high, and the leaves are always moist, which is a favorable condition for the disease if it is not dry. Last year's diseased body and soil residual germs can be repeatedly infected. The airflow caused the disease to occur repeatedly.

IV. Prevention and control measures

1. Prevention

If you choose the soil that has not been planted with potatoes, if there is a disease in the first year, then the diseased body and soil should be disinfected. Planting in the mountain area is better than the lower field, and the mountain area has good air permeability. It is convenient for drainage. It can be rotated with rape vegetables to reduce the source of bacteria. Nutrition satisfaction, maintain the best growth potential, resistance to bacteria. The field should not be closed, the planting density should be expanded and weeds should be weeded at any time, especially broad-leaved grass.

two。 Medication

Potato seeds can be soaked and sterilized with 0.2% potassium permanganate solution. If you get sick in the field, you can use 58% metalaxyl manganese zinc 500 times liquid spray. In fact, there will be a variety of drug choices, general drugs are used alternately, once a week. It can be treated after a few times.

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