Prevention and control techniques of mosaic virus disease in orchids to understand the cultivation techniques of edible fungi

Cymbidium mosaic virus disease, also known as necrotic mosaic disease and black stripe necrosis disease, is caused by national orchid mosaic virus (CyMV) and tobacco mosaic virus (TMV). It is one of the most common Cymbidium virus diseases. National orchid mosaic virus and tobacco mosaic virus have a wide range of hosts, including orchid, shrimp ridge orchid, Dendrobium, Paphiopedilum, Magnolia and so on. They are stable in nature and can usually survive in the sap of diseased plants for a long time.

Therefore, when the orchid strain is transplanted or propagated in different pots, once the orchid plant becomes sick, it will be transmitted to other orchid strains through operating instruments and matrix infection, and then transmitted to the healthy orchid strain cells through the wound to cause infection. Family orchid cultivation is often due to limited space, placed too dense, orchid leaves often overlap and squeeze each other, when affected by external forces (such as wind, watering, sprinkler irrigation or moving), the leaves often rub against each other and increase the chance of injury. the virus can also cause wound invasion and infection. Some growers adopt three-dimensional arrangement in order to save space, and the excess water leaked from the upper orchid plant during watering will naturally splash down on the lower orchid plant, causing the virus to spread everywhere and invade through the wound.

Injured orchid plants often have different symptoms due to different growth environments, usually long strips of necrotic tissue appear on the lower surface of the leaves, causing the death of the leaves, but the flowers can be disease-free. About 3 weeks after infection, the new buds appear irregular yellow spots, which become more and more obvious and increase as the leaves grow, and then become brown or grayish brown necrotic spots. There are also some varieties with rectangular, yellowed intermittent lines after infection, and then blackened and necrotic, and the black necrotic area may also spread to the entire leaves.

Like other plant virus diseases, orchid mosaic virus disease has no effective control methods at the current level of science and technology. therefore, we should pay attention to observation at ordinary times, and once suspicious plants are found, they should be isolated or burned immediately. Improve environmental hygiene, disinfection utensils, regular spraying to kill insects (aphids), etc., to prevent its spread. At present, the commonly used disinfectants are 2% formalin and 2% sodium hydroxide aqueous solution, both of which have good results. Tools and environmental disinfection can be prepared with 164g anhydrous or 337g sodium phosphate containing crystalline water plus 1000 ml of water. Usually do not buy virus-carrying vaccine or suspected virus-carrying vaccine, let alone obtain explants from diseased or suspected virus-carrying plants for tissue culture. If the conditions permit, it is best to test the mother strain for virus detection to make sure that there is no virus infection before use.