How to prevent and control eggplant damping-off? A detailed explanation of the latest control methods
Eggplant damping-off mostly occurs in the early stage of eggplant seedlings. Before the seeds emerge, they are susceptible to damage, often causing seed rot. After emergence, during the cotyledon stage or the early true leaf stage, damage causes seedling damping-off. In the early stage of the disease, the base of the seedling stem becomes discolored and necrotic, gradually loses water and shrinks into a thread-like shape. The cotyledons have not yet wilted, and the seedling has already fallen to the ground. When humidity is high, white cottony mold can be seen on the affected parts and on the ground surface. Now let's take a look at the control methods for eggplant damping-off!
Symptoms
When seedlings are infected and develop the disease, the base of the stem appears light yellow-green and water-soaked, as if scalded by boiling water, and quickly turns yellow-brown and spreads around the stem. The diseased tissue rots, dries up, and becomes sunken, producing mycelium. The water-soaked symptoms continue to spread from bottom to top. Before the cotyledons have wilted, the seedling falls over on the ground, then wilts and loses water, and further dries up into a thread-like shape. In the early stage of the disease, only a few seedlings in the seedbed are affected. After a few days, the disease gradually spreads outward with this as the center, and finally causes patches of seedlings to damp off. In plots with a high disease base, seedlings are often infected before emergence or just as the embryo sprouts, showing water-soaked rot, causing seed rot and sprout rot. When humidity is high, white cottony mycelium grows on the surface of diseased seedlings and on the nearby soil surface.
Disease Pattern
The pathogen overwinters in the soil with diseased residues. When conditions are suitable, it spreads to seedlings through rainwater or irrigation water, invades from the base of the stem, and has an incubation period of 1 to 2 days. The pathogen favors high temperatures of 34 to 36°C, but can also grow at low temperatures of 8 to 9°C. Therefore, when the seedbed temperature is low, seedling growth is slow, and high humidity occurs, the susceptible period is prolonged, making damping-off very likely to occur. Especially when continuous rainy weather occurs during the seedling stage, with insufficient light, seedlings grow weakly and the disease is severe.
Control Methods
1. Use rapid seedling raising or soilless seedling raising methods, strengthen seedbed management, ventilate timely and appropriately according to seedling condition, avoid low-temperature and high-humidity conditions, and do not water on rainy days.
2. Select damping-off-resistant varieties according to local requirements. You can choose Purple Round Eggplant, Dengpao Hong, Zhusi, Nanjing Zidan, Five-Leaf Eggplant, Seven-Leaf Eggplant, etc.
3. Treat seeds and soil with chemicals. Soak seeds in a 500-fold dilution of 53% metalaxyl-mancozeb water-dispersible granules for half an hour. Sow after soaking or sow directly. Take 50 kg of sieved nutrient soil, add 20 g of metalaxyl-mancozeb water-dispersible granules and 10 mL of 2.5% fludioxonil, mix thoroughly, and then fill into nutrient pots.
4. The seedbed should be selected as a disease-free plot with high and dry terrain, sheltered from wind and facing the sun, with good drainage, and loose and fertile soil. To prevent diseased mycelium from being brought into the seedbed, apply thoroughly decomposed farmyard manure. Before sowing, the seedbed should be fully turned and sun-dried, and raked level.