1, downy mildew
Chemical control: spray 40% Diyiling wettable powder, 500% Chlorothalonil wettable powder and 600 ~ 800% Nitrocellulose aqueous solution every 7 ~ 10/0 for 2 ~ 3 times continuously.
2. Black spot disease
Chemical control: 600 times of 70% mancozeb wettable powder, 600 times of 75% chlorothalonil wettable powder or 400 times of 64% antiviral alum wettable powder are selected for spraying.
Extended data
Growing environment of carrot: the seeds of carrot are easy to germinate at 20 ~ 25℃, and the required time is about 5 days; The stems and leaves are most suitable to grow at 23 ~ 25℃, and the seedlings can tolerate high temperature above 27℃. The suitable temperature for taproot expansion is 13 ~ 18℃.
Carrots require high illumination, especially during fleshy root hypertrophy, so we must ensure sufficient illumination, otherwise the yield will be reduced and the quality will be affected. During planting, the soil should be moist, especially during germination. If the soil is too dry during plant formation, the fleshy roots will become smaller, rougher, irregular in shape and hard in texture.
Carrots are suitable for growing in loam or sandy loam with deep and fertile soil layer and good drainage. In order to leave enough room for roots to grow, the cultivation container should be at least 40 cm wide and 40 ~ 50 cm high.
Baidu encyclopedia-carrot