Onions have a bactericidal effect. Many people like to eat onions. Onion purple spot disease is a fungal disease caused by A. grisea. So how to prevent onion purple spot disease?
First, the onion purple spot disease agricultural control more application of base fertilizer, top dressing, so that onions grow robust, enhance disease resistance. After the onset, it is necessary to control the irrigation to reduce the soil moisture and prevent the Hummer from being prevented from causing wounds.
Second, onion purple spot disease drug control seeds soaked with 40% formaldehyde 300 times liquid for 3 hours, washed in time after immersion. In the early stage of the disease, spray 75% chlorothalonil WP 600 times solution, 64% antivirus WP WP 500 times solution, 80% green Henson manganese zinc 500 times solution, 40% Dafudan 500 times solution, 50% Sprayed by 1500 times liquid, 2% polymycin 30ppm, 50% kelicin 30-50g, onion and garlic pathogen. Any one of the above agents may be used, and various agents should be used alternately, once every 7-10 days, and continuously controlled 3 times. Add 5-10 grams of neutral detergent to each 10 kg of liquid to increase the adhesion of the solution.