How to prevent and control pepper damping-off disease? Latest technical method tutorial

Damping-off is one of the important diseases of pepper at the seedling stage. It is distributed throughout the country and is often caused by unsuitable temperature and humidity during seedling raising and extensive management. When the disease is severe, it often causes seedlings to lodge and die in patches. In addition to harming pepper and other solanaceous vegetables, the disease can also damage the seedlings of cucumbers, melons, lettuce, celery, Chinese cabbage, cabbage, radish, onion and other vegetables. When autumn seedlings are infected, the base of the stem becomes yellowish-green and water-soaked, then quickly turns yellowish-brown and develops until it encircles the stem. The diseased tissue rots, dries up and becomes sunken, producing constriction. The water-soaked area expands from bottom to top, and the young seedlings lodge on the ground. At the early stage of the disease, only a few seedlings in the seedbed are affected. After a few days, it gradually spreads outward from this center, eventually causing seedlings to lodge and die in patches.

Occurrence pattern of pepper damping-off

The pathogen overwinters in the soil as oospores and survives adverse environments. In the spring of the following year, when suitable conditions are encountered, it germinates to produce sporangia and releases zoospores or directly produces germ tubes to invade the host, or the mycelium lives saprophytically in diseased residue tissues or on humus. In the following spring, it produces sporangia and zoospores that infect seedlings, causing damping-off in seedlings. The pathogen is spread by rainwater and irrigation water. Agricultural activities such as applying contaminated fertilizer and transplanting can also spread the pathogen.

The main factors affecting the severity of damping-off are soil temperature, humidity, light and seedbed management level. High soil water content, humid air, and temperatures between 30——36℃ or 8——9℃ are suitable for pathogen growth, but not conducive to seedling development, so the disease is severe. Improper seedling-stage management often also provides conditions for disease occurrence, such as sowing too densely, flood irrigation, improper ventilation for heat preservation, excessive seedling growth, and freezing injury. In addition, low-lying terrain, poor drainage, heavy clay soil and the application of undecomposed compost also make the disease more likely to occur.

Prevention and control techniques for pepper damping-off

1. Reasonably select the seedbed. The seedbed should be selected in a disease-free plot with high and dry terrain, shelter from wind and sunny exposure, convenient drainage and irrigation, fertile soil and good air permeability. To prevent the seedbed from carrying pathogens, decomposed farmyard manure should be applied.

2. Seedbed treatment. Before sowing, the seedbed should be fully turned and sun-dried. Old seedbeds should be treated with seedbed soil treatment. Commonly use 50% carbendazim wettable powder at 8——10 grams per square meter of seedbed, add 5000 grams of fine soil, and mix evenly. Take 1/3 of the medicated soil as a base layer, and after sowing, use the remaining 2/3 of the medicated soil as a covering layer.

3. Seed disinfection. Promote germination before sowing to shorten the time the seeds remain in the soil.

4. Strengthen cultivation management

① Implement a 2-3 year crop rotation with non-solanaceous and non-cucurbit crops.

② Cover with plastic film to block pathogens in the soil from splashing onto the plants and reduce infection opportunities.

③ The seedbed soil temperature should be maintained above 16℃, and the air temperature should be maintained between 20-30℃.

④ After the seedlings emerge completely, pay attention to ventilation, and at the same time strengthen soil cultivation and loosening to prevent excessive humidity in the seedbed. Keep the seedling-raising equipment well transparent to light, increase light, and promote healthy and strong seedling growth.

⑤ Remove diseased plants promptly when found, concentrate them for watering and destruction, and prevent the disease from spreading.

5. Chemical control. After diseased plants are found, promptly handle diseased leaves and diseased plants, and spray pesticide comprehensively for protection.

① During the seedling stage, use “Qingku Like” 50-100ml for spraying, once every 7 days, for 2-3 consecutive sprays.

② Remove diseased seedlings immediately when found, and promptly spray “Qingku Like” 50-100ml + “garlic oil” 7ml mixed with 30 jin of water in a large water volume, once every 3-5 days, for 2-3 consecutive sprays.