Control measures for rape downy mildew and white rust
1, downy mildew: the early stage of diseased leaves appear light green spots on the front, gradually expanded into a polygonal or irregular shape, while the color faded from yellow to yellow, generally in the corresponding back grow white layer of downy mildew. After that, the lesions turned brown, and the severely damaged diseased leaves turned yellow and even dried up. 2, white rust: early stage of diseased leaves appeared light green small class points, after the yellow, the corresponding leaves grow a shiny white pustule-like spots, burst after the release of white powder, late disease leaves withered. Both diseases often occur concurrently on the same plant. The pathogenic bacteria damage the rapeseed moss, which may cause the swelling to bend and become a "head-turning". The flowers are damaged and the petal is changed to luster and not strong. The germination and invasion of suitable pathogenic bacteria with low temperature and humidity, and the development of pathogenic bacteria with high temperature and humidity. Therefore, in spring when the cold is warm, more rainy or more nitrogen fertilizer and low-lying, poor drainage, the incidence of the field is heavy. Prevention: Agricultural control: (1) Selection of Disease Resistant Variety (2) When a squid is found to be swollen, it should be cut out in time and brought out of the field and burned or buried deeply. 2. Chemical control: (1) At the seedling stage, a 1:1:200 Bordeaux mixture is sprayed on the back of the leaf, and it is generally controlled 1-2 times. (2) In the first flowering period, when the diseased leaf rate reaches 10%, the first prevention and treatment will be carried out; the prevention and treatment will be carried out every 5-7 days for the second time. If there are many yin and rainy days, it is best to control 3 times. The top and bottom of the vegetable strains should be sprayed. Use 50% Formamide WP 500 times, or 65% dexamethasone WP 500 times, or 50% nitridone WP 200 times, or 50% dan wettable powder 500 times Spray control. Electronic Lock Safe Box,Home Security Electronic Lock Box,Electronic Key Safes,Electronic Lock Hebei Tiger Brand Group Jia Bao Cabinet Industry Co. LTD , https://www.cntigersafe.com