Further Discussion on the Prevention and Control of Orchid "Bailasi" Disease

I once wrote in "ChineseOrchids" 1992 Issue 2 aboutorchiddisease "Bailasi" being a physiological disease, that is, a nutrient deficiency caused by poor nutritional conditions in the soil. So, can this argument explain the following argument by Mr. Zhang of Taiwan, China? Mr. Zhang of Taiwan, China believes: newly collected wild species, originally pure and robust with no flaws, will still be infected with viral disease due to improper environment and management (no ventilation and lack of water). This shows that orchids more or less carry latent viral disease. Or due to external factors, it changes from a negative reaction to a positive reaction, infecting the whole plant. The author believes this is possible! First, Mr. Zhang believes: "Poor environmental ventilation, excessively dry air,orchidsare prone to disease 'Bailasi'. And plant nutrition science also records: "Although soil moisture has a good effect on nutrient transformation, when there is too much water it easily causes the loss of available nutrients, and also easily causes poor aeration, affecting crop nutrient absorption. When soil moisture is too little, available nutrients decrease accordingly." From this it can be seen that the two are interconnected. It can be summarized as follows: excessively dry air and too little soil moisture easily lead to nutrient deficiency. Second, Mr. Zhang proposes: "Newly collected wild species, originally pure and robust with no flaws. Due to improper environment and management (no ventilation and lack of water), they will still be infected with viral disease. This shows that orchids more or less carry latent viral disease." The author believes that the problem is that no such conclusion can be drawn. For newly collected wild species, due to changes in environment and soil (that is, growing medium, the same below), as well as the change from the original natural mountain stream water (nutrient-rich) to artificial water supply (both monotonous and lacking in nutrients), the source of nutrients fororchidflowers will inevitably change. Therefore, it is not surprising that this causes nutritional imbalance inorchidflowers. In addition, no matter what plant, after a certain period of physical growth, due to interference from various factors (for example, frequent alternation of dry and wet soil easily causes potassium fixation, greatly reducing the potassium concentration in the soil solution and inducing potassium deficiency; while rice in its peak growth period, when deficient in potassium, reduces nitrogen absorption; when deficient in nitrogen, relatively reduces phosphorus and potassium absorption; when deficient in phosphorus, reduces nitrogen and potassium absorption), phenomena of unbalanced nutrient absorption will appear, forming a deficiency of one or more nutrient elements. Third, in order to find effective ways to prevent and control the orchid disease "Bailasi", many experts, scholars, and orchid-growing enthusiasts have carried out a large amount of beneficial exploration on this: Chen Huizhao, former director of the Chencun Orchid Garden in Shunde County, Guangdong Province, used plant ash (that is, the ash remaining after plant residues are burned) to prevent and control this disease and achieved certain results (according to available information: the composition of plant ash is extremely complex, containing various ash elements from the plant body, such as potassium, calcium, phosphorus, magnesium, sulfur, iron, silicon, etc., among which potassium and calcium are the most abundant, followed by phosphorus. From a fertilizer perspective, it is often used as a potassium fertilizer source, but for crop nutrition, it is not only potassium but also phosphorus and other elements that play a role), but it was difficult to consolidate and impossible to advance. In this regard, the author believes that it may be due to the change in pH (plant ash is strongly alkaline), which prevents orchids from reasonably absorbing various nutrient elements. Director Li Junzhan of the Chencun Flower Research Institute in Shunde County, Guangdong Province, has studied this disease for more than ten years, and the conclusion now reached is also: deficiency of trace elements (that is, nutrient deficiency). Taiwan, China scholar Mr. Zhang Fengrong also admits that this disease "cannot be cured by a hundred medicines," but he alone did not mention using nutrient elements (that is, trace elements or trace fertilizers) to treat the disease. The author believes that the beneficial explorations of the above three can be combined into one. (Zhu Yongyu)