Potato virus disease

Symptoms There are 3 types of common potato virus disease. Chlorophyll of mosaic leaves is unevenly distributed, showing dark greenish greenish greenish or yellowish greenish mottled mosaics. In severe cases, the leaves shrink, the whole plant is dwarfed, sometimes accompanied by veins and leaves transparent; necrotic leaves, veins, petioles and branches. Brown necrotic spots can appear on stems and stems. The development of lesions is connected to necrotic streak spots. When severe, the whole leaves are dead or wilting. The leaf-wedge type leaves turn upside down along the main vein or from the edge and becomes hard and leathery. Each leaflet is tubular. In addition, there was compound infection that caused potato plaque necrosis.

The pathogenic potato virus X (PVX for short) causes light mosaic disease on potatoes, sometimes with mottled or ring spots. The virions are linear, 480 to 580 nm long, and have a wide host range. Systemic infections are mainly of the Solanaceae family. The virus dilution limit was 100,000 to 1,000,000 times, and the inactivation time of the inactivated domain 68-75°C was more than one year in vitro. The potato virus S (Potato virus S, PVS for short) causes mild shrinking and mosaicism or non-obvious disease in potatoes. The virions are linear, 650 nm long, and their host range is narrow. Plants that are infested by the system are limited to a few plants of the Solanaceae family. The disease sap dilution point is 1-10 times, the passivation temperature is 55-60°C, and the survival time in vitro is 3-4 days. Potato virus A (PVA) causes mild mosaic or non-obvious disease in potatoes. The virions are linear, 730 nm long, and their host range is narrow, infecting only a few plants of the Solanaceae family. Disease sap dilution point 10 times, passivation temperature 44-52 °C, 12-18 hours of survival in vitro. Potato virus Y (PVY) causes severe mosaic or necrotic spots and necrotic streak spots on potatoes. The virions are linear and 730 nm long. The virus has a wide host range and can infect a variety of plants in the Solanaceae family. Disease sap dilution point 100 to 1000 times, passivation temperature 52-62 °C, in vitro survival period of 1-2 days. The potato leafroll virus (Potat oea fro 1 1 1 virus, abbreviated as PLrV) has a virosomal globular shape with a diameter of 25 nm. The host area of ​​the virus is mainly Solanaceae. Roll leaf disease was induced on potato, the virus dilution point was 10000 times, the passivation temperature was 70°C, the survival time was 12-24 hours in vitro, and 4 days survived at a low temperature of 2°C. In addition, TMV can also infect potatoes.

Transmission routes and onset conditions In addition to PVX, the above viruses can be transmitted through the aphid and sap. Field management conditions are poor, and the occurrence of locusts is very serious. In addition, high temperatures above 25°C will reduce the host's resistance to the virus, and it will also facilitate the propagation, migration, or disease transmission of the locust vector, which will facilitate the disease's expansion and increase the severity of the disease. light. Variety disease resistance and cultivation measures will affect the occurrence of this disease.

Control methods (1) Non-toxic seed potatoes are used, and non-toxic seed potato breeding bases are established in various places. The original farming fields should be set at high latitudes or high altitudes, and the diseased potatoes should be eliminated through various testing methods to promote the elimination of virus from the apex tissues. Production fields can also obtain seed potatoes through the second season or summer sowing. (2) Breeding or use of disease-resistant or disease-resistant varieties in areas where there is spotted mosaic disease and common mosaic disease, Pulsatilla chinensis, P. cinnamomea, P. aestivum, Zhengshu No. 4, Ummun 601, P. sinensis 161-2 may be used. , Dongnong 303, Hubei Potato No. 1, Hubei Potato No. 2, Kexin No. 1 and Guanghong No. 2 and other resistant varieties. (3) The prevention and control of locusts before and after the emergence of locusts, in particular, by locusts for non-persistent transmission of virus, stripe mosaic virus should be better. The use of pharmaceutical agents see this book locust control law. (4) Improve cultivation measures. Including the retention of farmland away from Solanaceae vegetables; early removal of diseased plants; intensive cultivation, high ridge cultivation, timely soil cultivation; to avoid partial application of nitrogen fertilizer, increase phosphorus and potassium fertilizer; pay attention to cultivator weeding; control autumn water, prevent flooding. (5) In the early stage of disease, spray anti-virus (0.5% mushroom proteoglycan hydrolyzate) 300 times or 20% virus A wettable powder 500 times, 5% bacteria water solution 5. 0 times liquid, 1.5% plant disease Ling K emulsion 1000 times, 15% virus will be WP 500 to 700 times.

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