The latest control methods of cucumber leaf blight

Cucumber leaf blight mainly harms leaves, the symptoms of young leaves are not obvious, growing leaves appear yellowing areas, abnormal water-immersed chlorotic spots, gradually enlarged into near-round or polygonal brown spots, 1mm in diameter, surrounded by faded green halos, the back of diseased leaves is very easy to produce small bright veins in the early morning or cloudy days, let's take a look at the prevention and control of cucumber leaf blight.

Incidence regularity of cucumber leaf blight

The pathogen overwintered mainly with the mycelium in the soil with the disease residue, and produced conidia in the next spring, which were infected by airflow, and then produced conidia on the diseased leaves for re-infection. Weak plants, waterlogging in the field and high humidity are easy to induce the occurrence of the disease.

Incidence characteristics of Cucumber Leaf Blight

The pathogen likes the environment of low temperature and high humidity, the suitable temperature range is 3: 30 ℃, the optimum environmental temperature is 8: 20 ℃, the relative humidity is more than 95%, and the most suitable growth period is from seedling stage to adult stage. The incubation period of the disease is 7-15 days, which occurs only in the protected area, and usually occurs only in the period of low temperature in early spring. When the temperature in the greenhouse exceeds 25 ℃, the disease will be inhibited.

Control methods of Cucumber Leaf Blight

1. Apply sufficient basic fertilizer, drain water in time after rain, and ventilate and penetrate the light between the rows of plants.

2. Collect seeds from disease-free plants and select disease-free seeds.

3. In the protected cultivation shed, the ditch system should be cleaned in time to prevent stagnant water after rain, timely ventilation and ventilation, light watering and frequent watering should be adopted in fertilizer and water management, watering and fertilization should be in the sunny morning, and the shed should be opened in time for ventilation and humidity reduction.

4. Advocate interannual rotation with non-Cucurbitaceae crops in order to reduce the source of pathogens in the field.

5. remove the diseased old leaves in time during the epidemic period of the disease, clean the countryside after harvest, remove the diseased body, and take it out of the field to bury or burn deeply, turn the soil deeply and accelerate the decay and decomposition of the diseased body.

6. Before watering or in the morning of sunny day after rain, Bordeaux solution (1 / 1 / 1 / 200) should be selected for spray prevention, or mancozeb should be selected to prevent and cure the disease at the initial stage.