Symptoms and Control methods of main Diseases of Potato

1. Late blight

The main results are as follows: 1. Symptoms identify that the disease is a fungal disease, which harms stems, leaves and potato tubers. brown water-stained spots appear in the damaged parts of stems and leaves, and then expand into black patches. When wet, there is a circle of white mildew around the disease spot, and the back of the leaf is very obvious. after the potato block is damaged, brown or blue disease spot occurs at the initial stage, and then expands, the surface is gradually sunken, and the potato meat in the lower layer of the disease turns brown.

2. The selection of disease-resistant varieties is the most economical and effective way to control late blight, such as Wushu 8, 9, 11, Longshu 3, 5, etc.; select disease-free seed potatoes to eliminate the source of infection; eliminate central diseased plants and prevent them by spraying in time. When the central diseased plant is found, it should be eliminated in time, and chemical control should be adopted. Generally, 58% Baodasen 100g is mixed with water 3 times per mu, foliar spray is carried out with sprayer, spraying every 7-10 days, continuous spraying 2-3 times can achieve the ideal control effect.

2. Early blight

The main results are as follows: 1. The symptoms mainly harm the leaves, and the potato pieces can also be damaged. The occurrence of the disease is earlier than the late blight. Generally, the disease occurs first from the lower old leaves, and begins to form brown spots on the leaves, and then expands into dark brown spots with concentric wheel lines, so it is also known as wheel disease spots, with a clear boundary between disease spots and disease-free tissue, and the leaves dry up in severe cases.

2, after the potato piece is infected, the disease spot is round or irregular, dark brown, slightly concave, the potato meat turns brown, dry rot, and there is a layer of corked tissue below.

3. The control methods include selecting disease-resistant varieties, applying more fertilizer, strengthening field fertilizer and water management, improving plant disease resistance, removing diseased and residual tissues, and rotation with non-Solanaceae crops. 58% Bordeaux or 0.8% Bordeaux solution was sprayed for 3 times at the initial stage of the disease.

III. Ring rot

The main results are as follows: 1. The disease is a bacterial disease, which is transmitted by seed potato. After sowing, the heavy ones rotted and did not emerge, while the light ones emerged, but the internodes were shortened, the plants were short, the plants began to fade from the edge of the lower leaves, gradually withered upward, and finally withered, but the leaves did not fall off. The susceptible potato pieces were squeezed by hand to produce yellow bacterial liquid, the potato skin was separated from the potato meat, the serious ones were cracked, the potato meat was rotten and smelly, and the lightly susceptible potato pieces had obvious rings after cutting.

2. the prevention and control methods are transferred from disease-free areas to promote resistance to ring rot, and those who have cut diseased potatoes are sterilized with 75% alcohol or salt water and then cut to prevent infection; bud planting: remove diseased buds and weak bad buds, and select disease-free buds. It can improve the seed character and increase yield, establish disease-free seed field, and provide seed potato with high purity, disease-free and light degradation.

IV. Virus disease

The typical symptom of common mosaic disease is that the leaves show dark green and yellowish light mosaic along the veins, and the leaves shrink slightly and wrinkle to a certain extent. Speckles are obvious in shade or cloudy days: manifested or concealed in strong sunlight.

Stripe mosaic disease or heavy mosaic disease, the leaves of the susceptible plants showed mottled mosaic or withered spots at the initial stage, developed vein necrosis in the later stage, and appeared brown stripes along the petiole to the main stem in severe cases. The leaves were completely necrotic and wilted, and the lower leaves were necrotic in the form of vertical leaves, but did not fall off. After some varieties were susceptible to the disease, although there was no necrosis, the plants were short, the stems and leaves became brittle, and the leaves showed the shape of common mosaic disease.

After the compound infection of striped leaf taro common mosaic virus, the plant showed the symptom of shrinking mosaic, the leaf became smaller, the top leaf shrunk seriously, the leaflet tip and edge bent downward, the plant was significantly short, hydrangea-shaped, did not blossom, mostly died in the early stage, and the tuber was very small.

Disease-resistant and disease-tolerant varieties were selected by control methods, and 800-1000 times solution of dimethoate EC was used to control aphid transmission according to the occurrence law of aphids.