Detailed Explanation of Pest and Disease Control Methods and Technical Key Points

　　Pests and diseasesrefer to the harm caused by insects and fungi toorchids. Relatively speaking, the harm caused by insect pests is much less than that caused by fungi. Insect pests are relatively easy to control, while the control of fungal diseases is extremely difficult. This is because fungal disease control work is highly academic and scientific in nature. The author has not engaged in scientific research in this area, and knows little about the generation of pathogens, their naming, pathogen gene sequencing, variability, low-temperature tolerance and high-temperature resistance, as well as the temperature and humidity suitable for their reproduction. Therefore, when discussingpest and diseasecontrol work, there is no scientific basis. However, in order for us to groworchidswell, I will still briefly discusspest and diseasecontrol based on experience, with the intention of exploring together with fellow orchid growersorchidpest and disease control methods, and I earnestly request experts to make a scientific judgment on common orchid pathogens. Pest and disease control work should center on the approach of putting prevention first and treatment second, and prevention work should be done conscientiously. 1. Strong plants are not infected. Large, strong seedlings are generally very healthy themselves, do not carry fungal bodies, and have strong disease resistance. Therefore, seedling selection work is very important. Strong seedlings are the fundamental guarantee for resisting and suppressing fungi. Orchid plants are like people: those with weak constitutions are prone to many illnesses. Therefore, when selecting seedlings, do not seek only cheapness; strong seedlings are better. Find ways to grow the plants strong to reduce fungal harm. 2. No matter what kind of seedling, before potting it should undergo sterilization. For normal seedlings, one of 1/2000 thiophanate-methyl, carbendazim, mancozeb, or carbendazim may be selected to spray the whole plant. Diseased seedlings should be soaked and rinsed with medicinal solution, dried, and then potted. The chemicals used for spraying and soaking plants should not be reused in future pest and disease control work, so as to avoid the orchid plants developing antibodies and failing to achieve the control effect. 3. Under normal circumstances, disinfecting the growing medium by exposing it to the sun for one midday during the dog days is sufficient. Used growing medium should also be exposed to the sun before use. As for the growing medium of orchid plants that have developed disease, it is best not to use it. If it must be used, it should be subjected to high-temperature boiling and steaming. Place the orchid pot on a fire and heat it to above 80°C, which can prevent pathogens from regenerating. 4. Wild-collected plants and division-propagated orchid seedlings both have wounds on their surfaces, and wounds that have not yet formed scabs are likely to cause infection. Pathogens that infect through the roots are more harmful to orchid plants, are easily transmitted, and are not easy to detect. Therefore, division-propagated orchid plants should promptly have their wounds smeared with chlorothalonil or thiophanate-methyl dry powder, be fully dried in the shade, and then potted.Wild-collected orchidplants should be rinsed clean, then soaked for ten minutes in 1/1000 chlorothalonil solution, fully dried in the shade, and then potted. When potting orchid plants, be gentle and do not press the growing medium with force, so as not to damage the root system and pseudobulbs. When potting, adjust the growing medium to semi-moist and semi-dry (about 50% water content), place it in a cool, ventilated place, and according to the water-retention performance of the growing medium, water thoroughly after 3-5 days. This can effectively avoid wound infection. Orchid plants cultivated on balconies should be kept as far away from the orchid rack as possible, to avoid mechanical injury and pathogen infection caused when wind makes the orchid leaves sway. Pathogen infection is the result of pathogen replication. So-called pathogen replication is the massive reproduction of pathogens. Therefore, the fundamental measure for controlling pathogens is to inhibit their reproduction. However, since our understanding of pathogens has no sufficient scientific basis, there is no accurate method either. Therefore, preventing pathogen infection is extremely important. The above 4 items are the main preventive measures for our orchidflowercultivation. In the process of growing orchids, pathogen control work must still be carried out in combination with weather temperature and humidity. Practice has proven that doing pathogen control work well during rainy days in the growing season is extremely important. 5. Pruning diseased leaves: As mentioned earlier, pathogen infection is the result of pathogen replication. Therefore, promptly cutting off diseased leaves is one of the main means of cutting off the source of pathogens. When pruning diseased leaves, attention should be paid to the following issues: scissors must be carefully disinfected. Alcohol, potassium permanganate, and other solutions can be used to wipe the scissors. After each disinfection, only one pot of plants may be pruned. When pruning the second pot, the scissors should be wiped with a cotton ball to avoid cross-infection. Try to finish pruning work before 20°C. According to the author's observation, most pathogens are relatively active above 20°C, and are most active when the temperature is around 28°C. Therefore, pruning work should be completed before pathogens become active. Pruning diseased leaves should be chosen on a clear morning at 10 o'clock, because at this time air humidity is low, which can avoid infection of wounds by pathogens carried in the air. At the same time, it helps the wounds form scabs the same day, reducing the danger of reinfection. On cloudy days, air humidity is high, so pruning is not suitable. After pruning, orchid plants should not be sprayed with water (or fertilizer) for 2 days, and after 3 days they can be brought back into normal management. 6. Medicinal prevention: When orchid plants enter the growing period, we should begin pathogen control work. Whenever it is cloudy or rainy and air humidity is high, there are also many pathogens carried in the air. Cephalosporin, penicillin, streptomycin, and others can be added with water at 1000 times dilution and sprayed. Adding a small amount of liquid foliar fertilizer can help the medicinal power penetrate the waxy layer of the leaves and improve the preventive effect. When the temperature reaches above 20°C, streptomycin can be selected for root drenching once. As the temperature gradually rises, pathogens become more and more active. Baishouqing, thiophanate-methyl, carbendazim, mancozeb, Du'an'ke, Bingdubike, Bingdukuaike, and others can be selected for spraying as preventive treatment. The disinfecting chemicals used at potting time should not be reused, and among the chemicals used in a year, try not to use any one for a third time. 7. Medicinal treatment: The above measures are preventive measures for orchid plant pests and diseases. Although we have carried out careful prevention work, when the temperature is 25-28°C, some orchid plants may still develop lesions. Therefore, at this time, carefully observe the growth condition of orchid plants and deal with lesions promptly when found. Anthracnose is one of the common diseases. The effective treatment method is to discover it promptly and treat it promptly. At the initial onset, the pathogen spores are very small, shaped like needle tips, and can be promptly discovered with careful observation. Apply medicine at 1/50 to the affected area. After 4 days, wipe it clean, and it can generally be cured. The earlier the treatment, the better. Anthracnose pathogens replicate extremely quickly on the leaf surface of orchid plants. When the environmental temperature is around 28°C, they can double their replication in 12 hours, and the harm is relatively great. Some people use "Dakening" (a medicine for athlete's foot) to smear the affected area with good results as well. Rust spot disease, mosaic disease, and others are treated the same way as above, and the medicines used are all sold at local seed stations. In our practice of growing orchidflowerplants, we may encounter a small number of stubborn cases that do not heal for a long time and are passed on from generation to generation. Such orchid plants can be appropriately divided in winter. After division, prune the remaining leaves and old roots, smear the wounds with medicine, soak them in medicinal solution for 20 minutes after 5 hours (generally medicine at 1/1000), dry them in the shade until semi-dry, rinse briefly with clean water, continue drying in the shade, and then pot them. Old growing medium and orchid pots should both undergo high-temperature disinfection. (Anhui Moshi Caotang, Song Mingyuan)