When the water is too wet or the ventilation is not good, the disease is the most serious, especially the seedlings which have just been planted are the most vulnerable. The infection site will produce brown spots, which will expand rapidly under the environment of high temperature and humidity, and finally present black spots.
Attention should be paid to ventilation and light transmission. The basin soil should be well drained to prevent the disease. After the disease, the basin soil with bacteria can be removed and the quintozene powder or lime can be sprinkled.
Too dense planting, poor ventilation, water imbalance or wounds and other susceptible diseases.
In the early stage of the disease, there will be obvious Brown sunken spots, and then gradually expand to form round irregular spots. In serious cases, gangrene will appear in the center of the spots.
Do not plant too closely. Increase lighting to ensure good drainage and ventilation.
To cultivate strong seedlings, do not move the plants frequently, so as to avoid injury and disease. Increase the application of P and K fertilizer to enhance the disease resistance of plants.
Cut off the diseased leaves in time, and smear the wound with 1 /500 times of large raw water solution and 1 /8 times of bacterial clean. Once a week, spray 1 /1000 times of tolbutine methyl or carbendazim.
The tip of the leaf produces small black spots, which gradually expand into irregular spots. The periphery of the spots forms dark brown, and the middle is light gray brown. When it is serious, it spreads the whole leaf, and finally withers and leaves.
Remove the diseased leaves and spray 500 times of dasheng-45 or 1000 times of Haosheng.
For susceptible plants, rain water should be avoided or suspended to prevent aggravation of the disease.
Spray 500 times of daweng-45 once a day for prevention.
