The Causes of Rotting Roots in Spring Cabbage Seedlings and the Countermeasures
While Suning Vegetable Farmer Wang is currently dealing with challenges in growing spring cabbages, the seedlings are facing several issues due to unfavorable weather conditions. In recent winters, cabbage seedlings often experience low temperatures and cold stress, which can lead to various physiological problems or diseases. Although this year's winter has been slightly warmer than previous years, it has been more foggy, resulting in high humidity and weak sunlight—both of which are not ideal for healthy cabbage growth. The recent appearance of rotting in cabbage seedlings can be attributed to a combination of factors. During periods of low temperature, high humidity, and poor air circulation, moisture evaporates slowly. If the seedbed is overwatered and the moisture cannot escape quickly, it creates an oxygen-deficient environment in the soil. This lack of oxygen hinders root respiration, leading to root rot. This winter has seen less snow and rain, but prolonged cloudiness and fog have kept the seedlings in a damp environment, increasing their susceptibility to disease. Another common issue is black stem disease, caused by the black stem borer (B. oleracea). The disease manifests as grey stems on cotyledons and true leaves, with small black spots. A long purple-black spot appears near the base of the stem, slightly sunken, and may spread to the roots. When severe, the fibrous roots decay, causing plants to wilt and die. The pathogen spreads through water and thrives in warm, humid conditions (around 25°C). Poor ventilation during sunny days can worsen the situation, leading to widespread infection and rot. Cabbage black rot is another serious problem. Infected seedlings show water-soaked lesions on the cotyledons, followed by black necrosis. At higher temperatures and humidity, the disease spreads, forming a "V"-shaped melanosis along leaf edges or veins, with small black spots on the veins. It can also cause plaque-like necrosis. The bacteria move through the vascular system, turning the vascular bundles black and spreading to the stems and roots. Black rot bacteria can also contribute to soil-borne infections, especially if the seedlings are already weakened. To prevent these issues, it's essential to prepare bedless soil before planting. The soil should be disinfected in advance. One method is to spray formalin solution and seal the area for 15 to 20 days, then open it once the smell has dissipated before sowing. At the time of sowing, covering the ground with carbendazim can help prevent bacterial infections. During the seedling stage, proper ventilation is crucial. Maintain daytime temperatures between 15°C and 20°C and nighttime temperatures between 8°C and 10°C. Avoid excessive heat, especially during cloudy, rainy, or snowy days. Strengthen temperature and humidity control, and ensure proper drainage. If the seedbed is too wet, avoid long-term ventilation due to low temperatures. Instead, sprinkle wood ash to absorb excess moisture. Watering should be carefully managed. Typically, seedlings are watered only at seeding, seedling, and transplanting stages. Otherwise, watering is minimal. Greenhouses and hotbeds should follow weather conditions—watering is best done after several sunny days. Ensure the seedbed receives as much light as possible, and provide scattered light during cloudy or snowy days to support healthy growth. Pedestrian Passing Equipment,Advertising Barrier Gate,Swing Wrought Iron Side Gate,Community Advertising Door Shandong Changchongyun Intelligent Technology Co., Ltd. , https://www.ccyparking.com