Controlling the three diseases of cold lettuce lettuce is the key: Lettuce downy mildew <br> Control measures: select resistant varieties, implement rotation or interplanting, strengthen field management, level the noodles, use sorghum cultivation to facilitate drainage and dehumidification, prevent flooding, proper close planting, and diligent weeds. Timely remove the diseased leaves in the lower part of the plant and increase the application of phosphorus and potassium fertilizers. In the early stage of the disease, 58% of metalaxyl and manganese zinc wettable powder 600 times solution, or 72.2% of ground mold water agent 600 times solution, or 69% of methicylmorpholine and manganese zinc wettable powder 600 times solution, or 50%. Dyson ammonium water 1000 times solution, or 5% chlorothalonil WP 500 times solution spray, spray once every 7 days, even spray 2 to 3 times. The agents are preferably used interchangeably. British Style Switch,Plastic Wall Switch,Electrical Wall Switch Rocker Switch Co,.Ltd , http://www.onbswitch.net
Prevention and control measures for lettuce virus disease: strengthen management. Adjust the sowing date according to local conditions, and do so at the right time. At the seedling stage, pay attention to small water and water, and avoid excessive seedlings. Spray foliar fertilizer at a suitable time to promote early plant growth. Prevent cockroaches and reduce the occurrence of diseases . At the beginning of the disease, 1.5% phytopathogenic emulsion 1000 times solution, or 0.5% mushroom proteoglycan water 300 times solution, or 20% morpholinium hydrazine acetate copper WP 500 times solution, or 5% bactericidal water clearing agent can be used. 200 to 300 times liquid, or 2% Ningnanmycin water 200-300 times liquid and other agents spray control. Spray once every 5 to 7 days, and spray 2 to 3 times.
Prevention and control measures of lettuce brown spot disease: balanced fertilization, keeping plants healthy and growing, and enhancing disease resistance. Pay attention to the field hygiene, collect the sick bodies in time and bring them out of the field for burning. In the early stage of the disease, 75% chlorothalonil WP 600 times solution, or 50% Pythium WP 1000 times solution, or 50% carbendazim WP 400 times solution, or 40% polysulfide suspension 500 times. Liquid, or 80% thiophanate-methyl WP 1000 times liquid and other agents spray control, spray once every 7 days, even spray 2 to 3 times.