Purple spot disease seriously withered green onion how to control purple spot disease of green onion

Scallion purple spot disease, also known as black spot disease, harm leaves, pedicels. More from the leaf tip and pedicel middle disease and then upward spread, appear purple-brown small spots or spindle slightly depressed spots. At the beginning of the disease, it was a white dot with water stains, then turned into a light brown round or spindle shape, and continued to expand, brown or dark purple. When humidity is large, scallions are full of dark brown or black gray mold, pink, generally arranged into concentric rings. The disease spots continue to expand, several disease spots even into long strips of large spots, leaves and pedicels infected softening easy to break, serious, a large number of leaves die. Control methods:

purple spot of Chinese onion

1. Implement rotation: onion rotation shall be implemented for more than 2 years.

2. Select disease-free seeds: select onion seeds from disease-free or lightly diseased fields.

3. Seed disinfection: Scallion seeds can be disinfected by soaking in 40% formaldehyde 300 times solution for 3 hours, and washed in time after immersion. Scallion bulbs can be disinfected by soaking them in warm water at 40~45℃ for 90 minutes.

4. Field management: choose flat loam with convenient drainage to plant scallion. In addition to applying enough decomposed high-quality organic fertilizer as base fertilizer, increase phosphorus and potassium fertilizer and control irrigation to enhance the resistance of scallion. Early control of onion thrips to prevent wounds, then introduced diseases.

5. Clean garden: frequently check the development of purple spot disease of scallion, timely pull out diseased plants, remove old leaves, diseased leaves and diseased flower stalks, bury them deeply or burn them. After harvest, timely remove the diseased bodies of scallion and deeply cultivate them.

6. Chemical control: before transplanting in continuous cropping land, after spraying agricultural antibiotic 120, chlorothalonil and carbendazim, transplant with medicine. At the initial stage of disease in the field, 500~600 times of 75% chlorothalonil WP, 500 times of 64% Sandufan WP, 500 times of 53% Jinlei Water Dispersible Granules, 1500 times of 50% Diprohydantoin WP, or 30 mg/kg of 2% Multi-antibiotic WP can be selected for control, spraying once every 7~10 days, continuously spraying 2~4 times. Because there is a waxy layer on the leaves of scallion, ordinary liquid medicine, poor adhesion, can be added to 10 grams-15 grams of neutral washing powder per 15 kilograms of liquid medicine, increase the adhesion of liquid medicine.