Control methods of Cucumber Blight

Cucumber blight can be infected from the seedling stage to the adult stage, and the seedlings begin to appear dark green and water-immersed rot on the tender tip, gradually drying up and forming a bald tip, which mainly harms the base of the stem and the nodes of the tender stem at the adult stage, and begins to be soaked in dark green water, then softens, constricts obviously, and the leaves above the affected parts gradually wither. Let's take a look at the prevention and control methods of cucumber blight.

Occurrence regularity of cucumber blight

Cucumber blight is a fungal disease, which overwinters with disease residues in soil or manure. The conditions in the coming year are suitable for sporangia to grow through wind and rain, irrigation and water droplets to spread. The appropriate temperature of the disease is 28 to 30 degrees Celsius, and the disease is easy to occur and spread quickly with large rainfall, more rainfall or more shallow water. Therefore, the disease is serious under the conditions of low-lying terrain, poor drainage and high humidity.

Conditions for occurrence of cucumber blight

The pathogen overwintered mainly by mycelium, oospore and chlamydospore in soil or manure, and spread by wind, rain and irrigation water. The optimum temperature for the disease was 2830 ℃, and soil moisture was an important factor affecting the epidemic degree of the disease. The epidemic disease is easy to spread and the harm is serious in the years with high temperature, heavy rainfall and more rainy days in summer. In addition, low-lying terrain, poor drainage, continuous cropping and other prone to disease. When protected cultivation, at the turn of spring and summer, after opening the vents in front of the greenhouse, it is easy to get sick quickly.

Control methods of cucumber blight

1. Agricultural measures: select disease-resistant varieties, such as Jinchun 3, Jinza 3, Jinza 4, Zhongnong 1101, Longzahuang 5, Zaofeng 2 and so on. Yunnan black seed pumpkin was selected as rootstock to raise seedlings by grafting. High border cultivation was used to cover plastic film to reduce the chance of pathogen infection to the plant. Avoid flooding and avoid excessive moisture in the soil and air. When cultivated in the open field, the stagnant water in the field should be discharged in time in the rainy season, and the diseased plant in the center should be pulled out in time.

2. Disinfection treatment: the effective method of seed disinfection is to soak the seeds with 25% metalaxyl wettable powder 800 times solution for 30 minutes and then accelerate germination and sow seeds. The method of soil disinfection in the seedbed or shed is to mix 8 grams of metalaxyl wettable powder with soil on the seedbed per square meter, and spray the ground with 750 times of metalaxyl wettable powder before planting in the protected field.

3. Chemical control: the key to the prevention and control of cucumber blight in the open field is to start spraying one week before the arrival of the rainy season, once every 7 days, three times in a row. The available agents are 64% alum wettable powder 1000 times, 25% metalaxyl wettable powder 600 times, leaf mildew fungicidal wettable powder 1200-1600x, 50% nail cream copper wettable powder 600x, etc. The practice shows that the prevention effect is very good when sprayed with 500 times of 70% mancozeb wettable powder or 200 times of Bordeaux solution with 0.80% Bordeaux.