The large area of ​​death of onion seedlings is cause
Answer: This is an onion seedling damping-off disease. It is caused by Pythium infestans, Pythium and Pythium, and it is the most serious disease in the early spring period. The main manifestations of damping-off are: the tip of the leaf, the leaves on the surface of the ground that rot quickly, the rotting part remains green, the diseased parts turn white and dry if they do not rot quickly, and the leaves become white and dry. , into a dead tablet. Prevention methods are as follows: First, soil disinfection before nursery 1. Divaleraldehyde disinfection. 2 weeks before sowing, the soil is treated with divaleraldehyde, 70-100 liters of water per liter, 30-50 ml per square meter is sprayed on the soil surface, and then the surface of the soil is covered with a plastic film. After 3 to 5 days of boring, the film is peeled off. Loose pine topsoil, placed 7 to 10 days after sowing. 2. Dressing double disinfection. Per square meter seedbed with 50% seed dressing double 8 ~ 10 grams, mixed with 10 ~ 15 kg dry fine soil dubbed medicine soil. When sowing, take 1/3 of the bottom of the medicine soil and 2/3 of the soil to cover the seed. 3.72% frost ureanitrile manganese zinc, 5 grams per square meter, the practice and the same. Second, spray prevention The best choice for the use of copper agents, such as chloramphenicol, megacopper, and copper hydroxide, is effective and has a long pot life. In addition can also choose frost ureanitrile, fluoromorpholine, dimethomorph, silver, etc. according to the instructions to spray, spraying should pay attention to the ground more spray, kill the surface of the mycelium, inhibit the underground hyphae. Because the onion leaves are upright and the foliar waxes on the leaf surface make it difficult for the pesticide mist particles to adhere and affect the efficacy, the fineness of the mist particles should be particularly emphasized in the prevention and control. The finer the mist particles, the better. It can also be used in combination with foliar fertilizers. Disclaimer: Some articles in this website have been transferred from the Internet. If you are involved in third party legal rights, please inform this website. phone Mask-Sheet Mask,Mud Mask Green,Blackhead Removal Mud Mask,Color Clay Masks Guangzhou Lingxue Cosmetics Co., Ltd , https://www.gzlxgj188.com