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Prevention and cure of lettuce sclerotia
The main symptoms of lettuce stem base prone to lettuce, infected parts of brown water stains were mostly rotten, high humidity, the Department of the Ministry of dense cotton flocculent surface mycelium, sclerotia later. The sclerotia are white at first, and gradually become murine fecal black particles. The wilted leaves of infected plants eventually caused the whole plant to die. Disease conditions The bacterium sclerotia is overwintering with the diseased body in the soil and rots in the water for one month. After the spores mature, they are transmitted by airflow. Healthy leaves in the field are infected when they come into contact with the hyphae. The disease became severe when the temperature was 20°C and the relative humidity was higher than 85%. Humidity is less than 70% and the disease is significantly reduced. Poor ventilation, good drainage, low-lying topography, partial nitrogen fertilizer application, and continuous disease severity. Control methods 1. Agricultural measures: Rational fertilization, increase organic fertilizers; bring planting, improve the quality of the cover film, make the film close to the ground, avoid the growth of weeds; use appropriate black mulch film, the uncovered ascular discs will be blocked Under the membrane; timely removal of diseased leaves or removal of diseased plants buried deep. 2. Chemical control: spraying 70% thiophanate-methyl WP wettable powder 700 times, or 50% acetaminophen wettable powder 1500 times, or 50% fast-inking WP 1500, or 40 % Sclerotium net wettable powder 500 times liquid, or 20% methylrhodamine EC 1000 times, every 7 days, continuous control three or four times.