Orchid Medication, Part Six: Correctly Understanding Jinggangmycin

With the arrival of the plum rain season in Jiangnan, the rainy, muggy, gradually rising temperatures are most suitable for the reproduction and spread of all kinds of fungi and bacteria. At this time, orchid gardens need to adopt measures such as chemical prevention, reasonable water control, attention to ventilation, and attention to shading to restrict the spread and outbreak of harmful bacteria. Among the pathogens that infectorchidsat the stem base and roots, southern blight is a pathogen whose disease progression is relatively rapid. It begins to develop at the orchid root-stem area near the ground surface. The main features are that the diseased part is water-soaked, yellow-brown to red-brown wet rot, covered with a white silky mycelial layer, mostly spreading radially, and often spreading onto the soil surface near the diseased part. In the middle and late stages of the disease, yellow-white sclerotia the size of rapeseed often appear in the white mycelial layer, later turning yellow-brown or brown, becoming the source of reinfection. The suitable temperature for the pathogen's development is 32 to 33°C, the maximum temperature is 38°C, and the minimum temperature is 13°C. After painful lessons, people found a relatively effective control agent in the process of preventing and treatingorchidsagainst southern blight, and this is jinggangmycin. China began industrial production of jinggangmycin in 1976, and jinggangmycin is the variety with the largest output and usage among China's antibiotics. Jinggangmycin currently has no substitute, and after several decades, no drug resistance has appeared. Only two countries in the world produce jinggangmycin: one is China, and the other is Japan. Jinggangmycin is an antibiotic produced by actinomycetes. The pure product is a white powder and is easily soluble in water. It has systemic therapeutic action and is stable at room temperature in neutral, weakly acidic, and weakly alkaline media, and easily decomposes in strongly alkaline and strongly acidic media. The aqueous solution appears as a brown transparent liquid with no odor, with a shelf life of 2 years; the water-soluble powder appears as a brown-yellow or brown loose powder, is weakly acidic, and has a shelf life of more than 2 years. Orchid enthusiasts mostly prefer to use powder products. It is low in toxicity to humans and livestock, and safe for fish and bees. The residual effect period can reach 15-20 days, and it can be mixed with a variety of fungicides. Jinggangmycin is mostly used to control rice sheath blight and rice false smut. On vegetables, it is mostly used for vegetable seedling damping-off and southern blight, etc. Onorchids, its application is one of the essential medicines mainly for preventing and treating southern blight. At present, most products on the market are 3% or 5% water-soluble powders, generally available at pesticide supply stations. If southern blight is discovered early, it is not necessary to lift the plants. You can directly spray the prepared 500-700 times dilution of jinggangmycin on the root base of the entire diseased pot, using it two to three times in succession, and it can basically be cured completely. Diseased orchids should be isolated for observation, and it is best to place them in a ventilated, semi-shaded spot with diffused light. In addition, the height of the potting medium should be lowered, and the medium covering the pseudobulb should be removed, allowing the pseudobulb part to be temporarily exposed to the air. First, this makes observation easier; second, it allows the pseudobulb to be in a relatively dry environment, which helps rapid recovery. After southern blight is cured, do not relax management. It is best to sprinkle a thin layer of plant ash around the diseased pseudobulb for reinforcement. When orchids are harmed by southern blight, adjacent orchids can be sprayed with jinggangmycin for protection, while others can be treated with plant ash for prevention. Treating southern blight should follow the principle of early prevention and early treatment, and the first treatment must absolutely not be delayed, otherwise the consequences are extremely difficult to control. Orchids after recovery should be kept slightly dry and cultivated cleanly, and water should not be poured over the crown. In short, after a serious illness, slow recuperation is needed. When storing jinggangmycin, attention should be paid to preventing high temperatures, sunlight, mold, and contamination by miscellaneous bacteria. In particular, when it cannot be used up in one go, attention should be paid to keeping the storage container sealed. (Gao Haiyong)