The origin of the orchid cancer virus and prevention methods, plus notes on hydrating edible fungi
According to documents from the Hualien area of Taiwan, China, there are currently at least 25 kinds of viruses infecting orchids, belonging to 9 virus groups, with Cymbidium mosaic virus, Cymbidium ringspot virus, and Orchid fleck virus being the three most common. This disease is a virus that cannot be cured in the near term, and it is contagious and hereditary, so orchid enthusiasts call it the "cancer" and "AIDS" of orchids.
After an orchid plant is infected with the virus, it causes systemic infection throughout the plant, making the orchid grow slowly, with spots on the leaves or irregular sunken yellow faded patches, and sometimes necrotic streak spots. They generally often occur at the base, middle, or part of the tip of the leaf, first appearing as milky white mesh-like streaks of varying length, thickness, and shape with irregular boundaries. The boundaries of the spots often resemble gradually spreading water stains, and the spot body appears chlorotic and transparent on both sides. In the early stage, the spot body has no abnormal-colored dots; in the middle stage, there is a sunken feeling on the back and a few light brown spots within spots appear; in the late stage, the color deepens to look like sunburn scorch, while shrinkage wrinkles appear, the leaf edges curl backward and lose their luster, then gradually dry up, and finally the plant dies. The dreaded Burras virus is contagious, and it will also be inherited by the next generation of orchid plants. Although it may not cause disease in time, it is like early-stage cancer. Bites and crawling of pests, pots, substrate, friction and compression on leaf surfaces, orchids displayed, stacked, transported together, watering by soaking pots, and reuse of old planting material can all spread the Burras virus, especially during division and repotting in spring and autumn, when tools such as scissors used to cut diseased orchid plants will inevitably be contaminated with the sap of diseased plants. When the tool cuts other orchid plants again, the virus in the sap originally stuck on the tool can enter cells through the wound and cause infection. During the spring and autumn repotting and division seasons, tools are used frequently, which often causes the virus to spread rapidly within an orchid garden. Some orchid gardens use vertical arrangement; when watering the upper layer of orchids, the remaining water flows to the lower layer, and the virus on the roots also spreads everywhere with the water. Although this method of transmission is slower, its impact cannot be ignored. In addition, in rural areas and flower and nursery farms where orchids are grown, because other crops and tobacco, sweet pepper, chili pepper, adzuki bean, and pea, as well as flowers such as daylily and lily, are infected with the Burras virus (CMT), transmission through aphid vectors also cannot be ignored. Since viral diseases cannot be controlled with drugs, only strengthening virus diagnosis and prevention can prevent the occurrence of viral damage. Usually, the following preventive work should be done well:
1. Do not blindly pursue varieties, do not be greedy for cheapness and buy virus-infected orchid seedlings, especially do not buy orchid seedlings from areas where virus-infected orchids are prevalent, and do not buy seedlings mixed and stored together with diseased seedlings. This is the most effective prevention method.
2. Newly purchased orchid seedlings must be carefully checked for whether they carry the virus before they can enter the garden.
Before entering the garden, they must be soaked for 2 hours in a medicinal solution of "Virus Bik" at 500-700 times dilution plus 250 times edible rice vinegar for disinfection. After potting, spray the leaf surfaces and backs once with a diluted solution of "Virus Bik". Every 10-15 days, water the roots once with this medicinal solution, for more than 10 consecutive times each. After that, spray once each season with medical aspirin at 1000 times dilution, so as to effectively inhibit the proliferation and spread of the virus.
3. Do not reuse the same cutting tool. When necessary, tools can be treated with a high-temperature flame, or soaked for 60 minutes in 10% bleach water or 2% formalin for disinfection. It is best to prepare several knives for alternating use when dividing plants, and immediately put them into disinfectant after use, just as medical scissors are kept in disinfectant at all times. When dividing plants, your hands should also be disinfected with disinfectant.
4. Do not excessively carry out high-temperature and high-humidity management just to pursue a high propagation rate and high growth rate. Orchid seedlings should not be planted too densely. An orchid garden must have natural ventilation. Various fertilizers should be supplied according to need; do not fertilize blindly, in case the result is the opposite of what is desired. Orchid gardens with available space are best cultivated naturally. High temperature and high humidity are the main causes of viral damage.
5. Prevent insects in the garden, especially aphids.
6. For pollen propagation, do not use virus-carrying orchids as the male parent.
Although the Burras virus is an incurable disease, it is not absolutely untreatable. The summarized methods are as follows:
1. Build up a strong constitution. Place diseased orchids in a naturally ventilated place, adjust light, temperature, and humidity well, create good ecological conditions, and provide suitable fertilizer and spraying to strengthen the plants and improve their antiviral ability.
2. Drug treatment: 1. For the finished pesticide Virus Bik, use a 500 times dilution as the effective medicine, add edible rice vinegar with very strong penetration at 250 times dilution to guide the medicine directly to the diseased part; 2. Apply heat-clearing and detoxifying Chinese medicinal materials: Isatis root, Daqingye, honeysuckle, skullcap, Andrographis paniculata, gardenia, Paris polyphylla, etc., select 3-5 kinds and combine them into a formula, and use them alternately every month. First use the infusion, then the decoction, and finally sprinkle the medicinal residue with the medicinal liquid, preferably at 10-100 times dilution; 3. Spray once each season with the analgesic aspirin at 1000 times dilution. Apply the medicine by both watering and spraying, spraying to treat the aboveground parts and watering to treat the underground parts. For comprehensive treatment, spray once every 7 days and water once every 10-15 days. After 10-15 consecutive times, change to once every half month or once a month, and persist for one year to consolidate the curative effect.
3. Support the healthy and dispel the pathogenic, gradually increase the amount of light, provide more natural ventilation, let the plants bathe in dew more, fertilize normally, water once every half a year with No. 2 trace element fertilizer and plant tonic, and spray once every half a month with a medium-concentration foliar fertilizer, such as Plant Power 2003, Gaolida, Gaole, and Aishi brand foliar fertilizer.
By making unremitting efforts according to this method, short-term curative effects can be obtained.