Control techniques of Potato Ring Rot in Alpine area

Potato ring rot is widely distributed and occurs in almost all areas where potato is cultivated, especially in Northeast China, which can reduce potato yield by 20% to 30%. It is a very serious bacterial disease, which can not only affect the yield of potato, but also affect the quality of potato, poor appetite, and bring serious economic losses to agricultural production. Therefore, management should be strengthened and timely prevention.

1 Distribution and harm

Potato ring rot occurs in Asia, Europe, North America, South America and other regions, in China, it is throughout the provinces, cities and counties, especially in the northeast, it can cause seedling shortage, yield reduction, cellar rot and other phenomena. In addition, due to the high infectivity of ring rot, producers have very strict requirements on the quality of seed potato. Once diseased plants are found in the seed potato field, they should be removed in time so as not to spread to other plants. All infected potatoes can not be used as seed potatoes.

2Pathogeny and epidemic

2.1Morphology: ring rot is a bacterium of Corynebacterium ring rot, the gram reaction is positive, no spores, no capsule, no flagella, can not move, cell size 0.4~0.6mm, most of them are wedge-shaped, and some are rod-shaped, curved or straight.

2.2 temperature: the suitable temperature for the growth of the pathogen was 20: 30 ℃, the highest was 31-33 ℃, the lowest was 1-2 ℃, and the lethal temperature was 50 ℃. The ring rot pathogen died after 10min.

2.3 Instruments infection: it can be transmitted through cutters, containers and utensils, so it must be sterilized before use. It can survive on containers and machinery for a long time, and the cutter can be strictly sterilized with 40% formalin 100 times solution.

2.4 cultivation conditions: the pathogen overwintered mainly in the susceptible tubers, which were stored in the cellar after harvest, or overwintered in the tubers left in the field, and passed on to the next year through autogenous seedlings, not in the soil.

3 symptoms

Ring rot is a disease of bacterial vascular bundles. The above-ground infection can be divided into two types: withered spot and wilting, mainly in the early stage of wilting type, wilting from the top compound leaf, the leaf edge slightly curled like lack of water, the disease spread downward, and the leaves of the whole plant began to chlorosis and droop, resulting in plant lodging and death. When the tuber occurs, the vascular bundles turn yellow, then dark brown, and the inner cortical ring forms an arc-shaped necrotic shape, so it is called ring rot, and the vascular bundles of seriously susceptible tubers become dark and rot.

4 prevention and control measures

4.1 selection of disease-resistant varieties, through experimental investigation, "Dongnong 303", "Dutch potato", "Russian potato" and other varieties have strong disease resistance and cold resistance, so they should be selected according to local conditions.

4.2 choose the appropriate plot, because the cultivation of potato is to harvest more high-quality tubers, and the tuber is weak and vulnerable to moisture and rot, and the ring rot is serious, so choose the sandy loam land with high topography, loose and fertile soil, deep soil layer and easy drainage and irrigation.

4.3 reasonable rotation and reasonable rotation can help to reduce the diseases caused by bacteria and reduce the incidence of diseases. Rotation can be carried out with cruciferous or gramineous crops for more than 3-4 years, but not with Solanaceae crops, so as to avoid the aggravation of diseases.

4.4 strengthen field management, shovel in time, and eliminate weeds in the field. Potato is often attacked by diseases and pests during the growth period in the field. If it is not controlled in time, the yield and quality of tubers will be seriously affected. Grasping the opportunity and early control is the main principle of pest control.

4.5 timely harvest storage cellar, cold in the north, harvest in time to prevent wet rotten potatoes, storage cellar should be dry and ventilated, the temperature should be suitable.