Control Methods of Potato Diseases

(1) conditions for the onset of late blight. Potato late blight, also known as blight and potato blast, is a destructive disease of potato. The disease is more serious in the plots with low-lying terrain, poor drainage, high humidity in the field, or excessive application of nitrogen fertilizer. When the temperature and humidity were suitable, the late blight spread rapidly and the diseased plants withered and died. (2) symptoms. The diseased leaves initially appeared round or irregular dark green watery spots at the tip and edge of the leaves, and became large brown spots after enlargement. When the humidity was high, a white mildew layer grew at the junction of the diseased part and the healthy part. The stem is damaged, with slightly sunken brown spots, and a white mildew layer is also produced when it is wet. Potato pieces were damaged and brown slightly sunken disease spots appeared. (3) Prevention and control methods. 1. Disease-resistant varieties and disease-free seed potatoes were selected. two。 Seriously diseased fields and non-eggplant vegetables should be rotated for more than 3 years, and spring potatoes and tomato fields should be 300-500 meters apart. 3. Strengthen cultivation management, rational application of nitrogen, phosphorus and potassium fertilizer, appropriate application of potassium fertilizer to enhance disease resistance. Trench drainage, reduce field humidity, timely removal of diseased plants in the field, and its centralized burning, in order to reduce the disease. 4. Chemical control. In the early stage of the disease, spray immediately to control its spread. Spray once every 5 or 7 days, 2 times in a row. The commonly used agents are 64% antiseptic alum 500 times 750 times, or 58% wettable powder 500 times, or 80% Dasheng wettable powder 500 times, or 40% Dakening suspension 500 times.

Second, ring rot (1) symptoms. Generally, symptoms begin to appear before and after flowering, such as shortening of diseased branches and stems, yellowing and wilting of leaf color, yellowing of leaf veins, and appearance of black-brown patches and slightly upward curling of leaf margin. There are no obvious symptoms on the outside of the lighter potato lumps, and the seriously diseased potato lumps turn dark brown, appear annular cavity, and sometimes complicated with soft rot, resulting in all rot. (2) Prevention and control methods. Select disease-free seed potatoes, completely eliminate diseased potatoes before seed retention and cutting, and disinfect knives before cutting potatoes. Remove the diseased plant in time when it is found. Pay attention to the control of underground pests, carry out crop rotation and select Hangzhou disease varieties.

Third, plaster blight (1) morbidity conditions. Potato bacterial wilt, also known as bacterial wilt, is a serious disease of potato. The disease is serious in areas with high temperature, high humidity and heavy rain. Planting seed potato with disease, continuous cropping land, low-lying land, acid soil, easy to occur. (2) symptoms. At the initial stage of the disease, the lower leaves wilted during the day and recovered in the evening. After two days, they no longer recovered and gradually developed from the bottom up. After 4 days, the stems and leaves of the diseased plants wilted and died. (3) Prevention and control methods. Potato can not be continuous cropped with Solanaceae, peanut and other crops, and rice rotation has a good disease control effect. It is necessary to strengthen cultivation management, select plots with high terrain and good drainage, and apply more organic fertilizer and potash fertilizer. Acid soil, before ploughing and raking, spread 50 kilograms of lime per mu, so that the soil is slightly alkaline and can reduce the disease. It was found that the diseased plants were immediately removed and burned, and the roots were irrigated with chemicals once every 7 days, continuously for 2 or 3 times, with 0.25 kg of medicine solution per plant, which had a better disease prevention effect. Commonly used agents are 500% carbendazim 700x liquid, or landscape dispersed granules 800x liquid, or can kill 1000 times liquid, or 20% limewater.

Fourth, virus disease (1) the cause of disease. Potato virus disease is a serious disease of potato, mainly due to the planting of seed potato with virus, extensive cultivation and management, lack of fertilizer and water, which will aggravate the disease. (2) symptoms. After the disease, the plant is deformed and dwarfed, and the yield is reduced, which can lead to the degradation of potato seed potato performance due to virus disease. After the potato was infected, it mainly showed two kinds of disease: wrinkle mosaic disease and leaf roll disease. 1. Wrinkled mosaic disease. The leaves are dark green and light green, the leaf shrinks, the leaf tip bends downward, shrinks, and the whole plant is dwarfed. two。 Leaf curl. The edge of the leaf curls upward and is cylindrical when it is serious. The diseased leaf is slightly smaller than the healthy leaf, the leaf color is lighter, and sometimes the back of the leaf is red or purplish red. (3) Prevention and control methods. 1. Strengthen cultivation management. Increase row spacing, reduce plant spacing, high ridge and deep furrow cultivation, apply sufficient base fertilizer, increase phosphorus and potassium fertilizer, reasonable irrigation, timely pull out diseased plants and reduce the disease. two。 Cure aphids and prevent diseases. After potato emergence, spray immediately to prevent aphids from spreading virus. 3. Chemical control. Spray 1.5% of Zhanling 1000 times and 20% virus A600 times, once every 7 days, for 3 times 4 times, the disease prevention effect is better.