Eggplant damping-off symptoms and treatment steps

What should we do if eggplant blight occurs when we cultivate eggplant? How can we better prevent and control it?

symptom

Eggplant damping-off disease occurs in the seedling stage, usually in the middle and late stages of seedling cultivation. Oval dark brown spots appear at the base of the stems of the diseased seedlings. In severe cases, the spots expand around the stems. After water loss, the diseased part gradually becomes sunken, dry and rotten. In the early stage, the large seedlings wilt during the day and recover at night. In the later stage, the stems and leaves wilt and die. The diseased seedlings wither and die, so it is called damping-off disease. When it is humid, a light brown spider-like mold layer appears. When the diseased seedlings are pulled up, the silk-like material is connected to the soil.

Eggplant damping-off

Disease pattern

The disease is caused by the fungus Rhizoctonia solani of the Ascomycetes. The fungus does not produce spores and mainly propagates through mycelium. The pathogen overwinters in the soil as mycelium or sclerotia and can live in the soil for 2 to 3 years. Mycelium can directly invade the host and spread through water flow, farm tools, and compost with bacteria.

The pathogen prefers high temperature and high humidity environment, and the most suitable condition for disease occurrence is about 20-24℃. The main peak period of disease occurrence in Zhejiang and the middle and lower reaches of the Yangtze River is from February to April. The susceptible growth period is the seedling stage.

The disease is more serious in fields with high soil moisture, uncomposted organic fertilizer, over-dense sowing, weak seedling growth, acidic soil, etc. The disease is more serious in years with frequent rainy weather during the inter-annual seedling raising period.

Prevention and control measures

Soil treatment

Use 40% seed-dressing double wettable powder, 8 grams per square meter, and the treatment method is the same as soil treatment for damping-off disease prevention and control. Or solar disinfection, that is, in the hot summer season, spread 1000-2000 kg of broken rice straw or wheat straw, or 750 kg of horse manure for every 667 meters, mix them, plow the land, fill with water, cover with mulch, and finally seal the greenhouse to increase the soil temperature and keep the ground temperature 20 cm underground above 45°C for 20 days. This method can kill most of the pathogens in the soil, and can also kill underground pests, and improve the permeability of the soil, which is conducive to plant growth.

Seed dressing with chemicals

Use 40% double wettable powder for seed dressing at 0.2% of seed weight, or 50% carbendazim wettable powder for seed dressing.

Agricultural measures

It is recommended to use nutrient pots to grow seedlings and use well-rotted organic fertilizers. In spring seedlings, watering is generally not required after sowing. You can use the method of spreading fine wet soil to maintain soil moisture. If the humidity is too high, you can spread plant ash to reduce humidity and pay attention to raising the ground temperature. In summer seedlings, shading measures can be taken to prevent high temperature and high humidity conditions. Spraying 0.1% to 0.2% potassium dihydrogen phosphate during the seedling stage can enhance the ability to resist eggplant damping-off disease.

Chemical control

In the early stage of eggplant damping-off disease, pull out the diseased plants and spray them with 800 times diluted 70% thiophanate-methyl wettable powder, 500 times diluted 50% carbendazim wettable powder, 1200 times diluted 20% lexapro wettable powder, 450 times diluted 15% soil fungus water-repellent, or 800 times diluted 75% thiophanate-methyl wettable powder.