Recently, due to the excessive fog and lack of sunlight, the humidity in the greenhouse increased, causing the occurrence of tomato early blight. Temporary Flood Boxwall,Mobile Flood Barrier,Flood Box Wall,Boxwall Flood Barrier Denilco Environmental technology(Suzhou)Co., Ltd. , https://www.wflood.com
Tomato early blight, also known as ringworm disease, is a relatively high incidence of tomato diseases. In addition to harming tomatoes, it can cause damage to eggplants, peppers, and the like. After the occurrence of the disease, it often causes defoliation, fruit drop, and black spots on the fruit. It gradually enlarges the appearance of rims and causes serious losses, which can reduce production by 20% to 30%. Therefore, it is necessary to prevent the occurrence of tomato early blight.
First, the symptoms
Tomatoes can develop from the seedling stage to the adult stage of the whole growth stage. The leaves and stems and branches are most susceptible to disease. Diseases generally start from the lower leaves and gradually expand upwards. The incidence of leaves produces dark brown round or oval spots, the diameter is generally 1-2 mm, the lesions are yellow outside. Yellow-green ring, lesions in the center of a concentric ring pattern, the ring pattern is more obvious, and gradually expand outward, so it is also called rosy ring disease, when the humidity is high, the surface of the lesion to produce part of the black mold layer. The lesions on stems, petioles and stalks were oblong, and when the disease was severe, the plants were easily broken off from the disease. After the fruit is damaged, many lesions are produced from the cracks in the pedicles. The lesions are round, slightly concave, dark brown, and long dark brown moldy on the lesions. They also have concentric ring patterns, fruit drop in severe cases, and light fruit disease. Easy to crack, early red, poor taste.
Second, the cause of the disease
The occurrence of tomato early blight has a direct relationship with temperature, humidity, leaf physiological conditions and disease resistance. Rainy and damp weather, the lack of sunlight can easily lead to the occurrence of the disease. The disease is a fungal disease. Pathogens are mainly transmitted by airborne infections. Excessive humidity is the main reason for the occurrence of tomato early blight. When the relative humidity of the greenhouse reaches 85%-95%, the germination rate is the highest. If it is improperly managed, it can easily cause widespread spread.
Third, prevention and control measures
Strengthen field management, implement proper close planting, and implement 2-3 year rotation with non-sweet potato vegetables. Choose good disease-resistant varieties, cultivate strong seedlings, soak in warm water before sowing. To keep the humidity of the greenhouse suitable, it should not be too large, timely removal of the diseased leaves, strains, and fruits. In the early stage, chemical drugs can be sprayed, such as 50% of the enemy bacteria WP 500 times, 75% WP 600 times, about 50 kilograms per acre, 96% copper sulfate available 200-300 times the Ministry of liquid coating disease, the effect is better, the drug should be used according to the specific circumstances of rotation, to prevent the emergence of disease resistance.