Detailed Explanation of the Latest Control Measures for Black Rot in Broccoli
Broccoli is a vegetable with high nutritional value. Due to expanding market demand, its planting area has also been increasing year by year, but the occurrence of black rot during cultivation seriously affects farmers' planting returns. So how should broccoli black rot be controlled? Let's take a look together.
1. Disease symptoms
The disease can occur from the seedling stage to the mature plant stage. When seedlings are affected, the cotyledons appear water-soaked, then quickly wither and die or spread to the true leaves; when mature plants are affected, the main damage is to the leaves, starting first from the leaf margins, then gradually expanding into V-shaped dead spots. The lesions are yellowish-brown with pale yellow edges. When the roots are damaged, the vascular bundles turn black, and the interior gradually develops dry rot until the entire plant wilts and dies. When the curd is affected, the disease spreads gradually from a single lesion on the surface of the curd, and in severe cases causes the entire head to turn black and rot.
2. Disease development pattern
Black rot is a bacterial disease. The pathogen is mainly spread through diseased plants, fertilizer, wind and rain, and farm tools. Generally, seed-borne bacteria, improper fertilizer and water management, or continuous cropping with cruciferous crops make this disease more likely to occur, and high-temperature and high-humidity environments also favor its development. The growth temperature of the pathogen is 5-39 degrees, with the optimum temperature between 25-30 degrees. When the relative humidity is above 95%, it causes dew to form on the leaves, and at this time the pathogen takes the opportunity to invade, causing leaf disease. During greenhouse cultivation, the high-temperature and high-humidity environment inside the greenhouse also makes black rot very likely to occur. When broccoli is forming heads, once water droplets on the greenhouse film drip onto them, black rot is extremely likely to occur.
3. Control methods
Choose varieties with strong disease resistance and carry out a 2-3 year rotation with non-cruciferous vegetables. Before planting, plow deeply and sun the soil, and cultivate on raised beds. This can both reduce field pathogens and improve field drainage. Adjust the temperature and humidity inside the greenhouse properly. First, do a good job with seedbed management. When cultivating in early spring, the temperature is relatively low, so pay attention to the frequency and amount of watering in the seedbed to avoid the occurrence of black rot. When cultivating in other seasons, the seedling temperature is relatively high, especially for winter-crop broccoli, so be sure to do a good job of cooling. In addition, after transplanting, water generally once every 7-10 days. After budding, more fertilizer and water are needed, so the frequency and amount of watering should be increased. After each watering, ventilate to lower the temperature and humidity. When diseased black rot plants appear in the field, spray agricultural streptomycin, streptomycin sulfate, new streptomycin, and other agents for control.
The above is an introduction to control measures for broccoli black rot. We hope it helps you. If you want to learn more related knowledge, please follow us.