Prevention and Control of Potato virus Disease

Potato virus disease is the main disease of potato. According to the symptoms, potato virus disease is often divided into two categories: potato mosaic disease and potato leaf roll disease. Potato mosaic disease is the main occurrence in most areas of our province, which generally reduces potato production by 20% Mel 50%, and serious ones by more than 80%.

Symptom

Common mosaic disease: after the plant is susceptible, the growth is normal and the leaves are spreading, but the leaves are light between the veins, showing different shades of mesophyll color. The leaves are easy to see yellow and green light flowers and leaves. In some varieties, the disease can be hidden at both high and low temperatures, and the damaged tubers do not show symptoms. However, there are certain differences with different potato varieties, environmental conditions and virus strains, and virulent strains can also cause shrinkage, stripes, necrosis and so on. Heavy mosaic disease: in the early stage of the disease, mottled leaves or withered spots are produced on the top leaves, and obvious black necrotic spots can be formed on both sides of the leaves, and can spread from vein necrosis to the petiole and main stem, forming brown stripes, making the leaves necrotic and withered and the plant wilting. The responses of different varieties were different, such as short plants, shortened internodes, common mosaic leaves and brittle leaves and stems. The plants with poisonous seed potatoes can be seriously dwarfed and wrinkled or striped mosaic-like, but also hidden disease. The tubers of diseased plants became smaller.

Wrinkled mosaic disease; the diseased plant is dwarfed, the leaf is small and severely wrinkled, the leaf tip bends downward, there are dark brown necrotic spots on the vein, petiole and stem, and the diseased tissue becomes brittle. When the damage was serious, the leaves shrunk seriously, withered from bottom to top, and the top leaves were mottled. The potato pieces of diseased plants are smaller and can also have necrotic spots.

Leaf roll disease: the typical symptom is that the leaf edge bends upward and becomes cylindrical when the disease is serious. At the initial stage, it appeared on the young leaves at the top of the plant, first faded, then curled upward along the midrib and extended to the old leaves. The leaves are small, thick and brittle, the veins are hard, the leaves are light, and the back of the leaves can be red or purplish red. Due to the destruction of phloem, black spots could be seen in the cross section of the stem, especially at the base and node of the stem. The tuber tissue showed reticular necrotic markings in the ductal area.

Spindle tuber disease: the damaged plant has few and erect branches, raised leaves, small and brittle, and often curled. Close to the stem, the internodes were shortened, and it was obvious that the plant grew slowly, the leaf color was light, sometimes yellowed, and the seriously diseased plants were dwarfed. The tuber becomes smaller and longer, and both ends are in the shape of a spindle. The number of bud eyes increased and prominent, the surrounding brown, smooth epidermis.

Disease control

1. There are many kinds of disease-resistant potato virus, and there are often several strains of a virus, and each strain reacts differently on different potato varieties, so virus-resistant breeding is very complex, and it is difficult to obtain varieties resistant to multiple viruses. Therefore, it is necessary to select and breed the main local viruses. At present, the widely planted virus-resistant varieties are Neishu 7, Atlantic, Zhongshu 2 and so on.

two。 Sowing in summer and keeping seeds in two seasons is an effective way to prevent the degradation of seed potatoes and to keep seeds in situ. In areas with short frost-free periods, normal spring sowing can be postponed to summer sowing (sowing from late June to early and mid-July). In areas with long frost-free periods, two crops of potatoes are planted in a year, that is, sowing in spring and autumn, and autumn sowing is used as seeds. In this way, seed potato is not only beneficial to the growth of potato, but also can control the speed of virus proliferation and expansion.

3. Chemical control has a significant effect on reducing degradation in time to control aphids, especially on leaf roll virus. You can also choose virus passivators, such as 20% poison poison, 2% Ningnanmycin and so on.

4. The purpose of strengthening cultivation management is to promote early maturity, to ensure yield increase, and to avoid tuber formation at high temperature. To this end, timely sowing according to local conditions, high border cultivation, rational use of fertilizer, uprooting diseased plants, ploughing and cultivating soil frequently.