What are the key points for orchid care in autumn? These methods must be mastered
1. Four major risks in growing orchids
In the process of growing orchids, orchid growers often face various risks. In the author's view, the main risks come from the following four aspects: first, the risk of buying fake flowers; second, the risk of orchids being stolen; third, the risk of orchid price fluctuations; fourth, the risk of orchids being killed by poor care. Among these four major risks, the first three are not necessarily encountered by everyone, but the fourth is faced by every orchid grower. From the author's survey results in recent years, within Dali Prefecture, among the cultivation situations of more than 110 orchid growers surveyed, there was no one who had never killed an orchid; there was only a difference between those who killed many and those who killed few, and the better and more famous the flower, the more likely it was to have problems. From the survey of just the 5 months from April to August 2005, within Dali Prefecture, the losses caused by orchid stem rot alone were estimated at between 100 million yuan and 500 million yuan. As for the exact amount of loss, only heaven and the earth know; it simply could not be counted. But what can be certain is that the amount of loss must have been very large. This year, stem rot of orchids occurred rather severely across the province and the whole country (here referring to stem rot in a broad sense, namely diseases caused by rot of the pseudobulb, including those caused by bacteria, fungi and various other pathogens). If the losses of the whole province and the whole country were added together, then the amount of loss would certainly be enormous. Therefore, how to grow orchids well rather than killing them is a major issue every orchid grower must face. Why has there been an outbreak of orchid diseases? Why have such great losses been caused? In the author's view, the main reason is that orchid growers, in the process of preventing and controlling orchid pests and diseases, have taken inappropriate countermeasures and have had many long-standing problems. The main problems existing in orchid pest and disease control found in the author's surveys over many years, along with countermeasures, are summarized below.
2. Main problems in orchid pest and disease control
1. Inaccurate diagnosis is the fundamental reason for severe occurrence of orchid pests and diseases
When we go to the hospital to see a doctor, what we most need is for the doctor to diagnose the illness accurately, and only then can the right medicine be prescribed; this is easy to understand. However, in the prevention and control of orchid pests and diseases, many orchid enthusiasts often rush to apply pesticides without having accurately diagnosed what disease or pest their orchids have. With such control, the efficacy is poor. Inaccurate diagnosis is the fundamental reason for severe occurrence of orchid pests and diseases.
2. Complex conditions for the occurrence of orchid pests and diseases are the objective reason for their severe occurrence
From surveys in recent years, it can be seen that with 100 orchid growers there are roughly 100 methods of growing orchids, mainly caused by differences in each person's growing conditions, experience and views on different cultivation methods. Because orchid-growing methods are diverse and growers' conditions differ greatly, the environmental conditions for growing orchids vary from one to another; because different growers have different orchid-growing techniques, the orchids they grow differ in vigor and weakness; because of these differences, the environmental conditions for the occurrence of orchid pests and diseases are also very complex, providing excellent conditions for the occurrence of pests and diseases on orchids, and ultimately the types of orchid pests and diseases that occur are diverse and vary from one to another. Taking orchid stem rot alone, if one relies only on the single point that the orchid's pseudobulb is rotting, it is impossible to make an accurate diagnosis. For experienced people, they must also see the actual specimen, isolate the diseased tissue, and conduct appropriate indoor culture before they can, with the aid of instruments, reach a preliminary conclusion. For ordinary orchid enthusiasts, diagnosing pests with the help of an illustrated guide to orchid pests and diseases may still be possible, but if diagnosing orchid diseases, the conclusion may not necessarily be very accurate. Otherwise, orchid stem rot (rot disease) would not have occurred so severely across the country.
3. Insufficient understanding of the characteristics, mechanisms of action and target pests/diseases of pesticides
From the surveys, it can be seen that regarding disease-prevention chemicals for orchids, many orchid enthusiasts know only two, carbendazim and thiophanate-methyl. When planting orchids, they use these two chemicals for disinfecting orchid plants, these two for preventing orchid diseases, and after orchids become diseased they still use these two for control. Doing so often means suffering losses in years when orchid diseases occur severely. This is because these two chemicals themselves both belong to the benzimidazole class of fungicides; with long-term use, pathogens easily develop resistance, and resistance to one of them means resistance to the other is correspondingly developed as well. Therefore, when using a certain pesticide, one must clearly understand that pesticide's mechanism of action and target pests/diseases in order to achieve the corresponding effect. Regarding the mechanisms of action of fungicides, it is necessary to clarify whether the chemical mainly plays a preventive role, a therapeutic role, or a pathogen-eradicating role against the pathogen, and also to understand whether the chemical has a systemic action or a contact-killing action, and so on; all such knowledge should be understood in order to apply chemicals in a targeted way. In fact, in orchid pest and disease control, the use of chemicals is very particular. What pest or disease requires what chemical for control must be clearly established. For example, for orchid bacterial diseases, if a fungicide for controlling fungi is used, the effect is generally poor or ineffective; and for diseases also caused by fungi, it is not the case that any fungal control chemical is effective; targeted use is required to improve control efficacy. This is the basic requirement for chemical use in orchid disease control. Here, it needs to be emphasized that a small number of chemicals, such as copper-containing fungicides like copper hydroxide, have a certain control effect on diseases caused by fungi, bacteria and viruses, but such broad-spectrum fungicides are generally mainly used for prevention; when used during the peak period of disease outbreak, no matter what disease is being controlled, the efficacy is generally not high. Relying mainly on such broad-spectrum chemicals to control orchid diseases often easily causes major losses.
4. Greater attention to pests and diseases on the middle and upper parts of orchids, but insufficient attention to pests and diseases of pseudobulbs and roots
From practical experience in growing orchids, many orchid enthusiasts pay insufficient attention to pseudobulb diseases and root pests and diseases of orchid plants, while in fact it is the latter two that are most devastating to orchid plant death. Most ordinary orchid enthusiasts take measures only after orchids have pests or diseases and have already shown symptoms. For pests and diseases on the middle and upper parts of orchids, emergency treatment still has a certain effect most of the time, but for pseudobulb diseases and root diseases, it is often already too late. In addition, what the broad community of orchid enthusiasts needs to pay attention to is the problem of pests in the orchid pot. There are many kinds of pests in the pot, and the damage is in fact relatively severe, requiring timely control (the author discusses this in a separate article).
5. Lack of systematic preventive measures and untimely application of chemicals
In the practice of growing orchids, we often see some people applying one chemical today, then tomorrow hearing others say another chemical is good, and switching to yet another. As a result, the control efficacy is often unsatisfactory. Therefore, to prevent and control orchid pests and diseases and achieve good efficacy, for a certain pest or disease, the same chemical with good efficacy must be used for continuous application. For diseases, apply at least 3 times consecutively (once every 7-10 days); for pests, apply at least 2 times consecutively, to achieve good efficacy. In terms of timing of control, one must grasp applying chemicals when pest numbers are relatively low, that is, what is commonly called treating early and treating small; for diseases, one must firmly remember the principle of prevention first and apply chemicals early; if orchids have already become diseased, one must seize the key period of the early stage of disease onset for continuous application. In addition, in the prevention of pests and diseases, one can apply chemicals in advance according to local common pests and diseases (on the premise of correct diagnosis), and firmly remember that the hot and humid season of the year (5-9 months) is the peak period for the occurrence of orchid pests and diseases, requiring timely prevention.
3. Countermeasures
1. Strictly implement disinfection measures for seedlings and growing media
Newly introduced orchid seedlings must undergo corresponding disinfection, sterilization and pest elimination methods to eliminate and reduce the spread of pests and diseases as much as possible, and cut off sources of transmission. When planting orchids, the tools used for dividing orchid plants, the growing media and the orchid pots should be disinfected. After many years of practice, the author believes that aside from the orchids themselves, the better measure is high-temperature disinfection; high-temperature disinfection can kill pathogens and pests, and is relatively thorough. The specific method is to put orchid-growing supplies, tools, growing media, etc. into boiling water and boil for 10 minutes, or use steam and steam them continuously for 30-60 minutes after the water has come to a boil. Other methods such as sun exposure or frying in a pan are also possible, but may not kill pathogens, pests and eggs 100%. This is the first step in growing orchids and must be done well.
2. Regularly prevent pests and diseases
In recent years, with the increase in large-scale and modernized orchid growers, many famous and fine orchids are of very high value, making doing this particularly important. In mid-August 2005, the author saw on a well-known domestic orchid website that a certain orchid enthusiast, because of stem rot occurring in orchids, within 15 days had 50-plus plants of the famous fine orchid Cheng Mei, worth more than 600,000 yuan, die from disease in one instance. This is a pity. Just imagine, apart from a small number of large operations, can the vast majority of orchid enthusiasts withstand such a blow? Therefore, doing a good job in orchid pest and disease prevention, especially prevention of devastating diseases, is very necessary. In terms of specific preventive measures, within Dali Prefecture, generally speaking, spring is mainly for preventing pests, with disease prevention secondary; the hot and humid summer is mainly for disease prevention, with pest prevention secondary; autumn is for preventing both pests and diseases; in winter, pests and diseases generally occur less, so targeted treatment can be carried out according to each person's situation. But in winter, special attention must be paid to protecting the orchid root system; if the pot soil is very humid in winter, orchids are most prone to root rot. There is a saying among orchid growers: nourish roots in winter, nourish leaves in summer and autumn, which makes a lot of sense.
3. Prescribe the right medicine
As mentioned earlier, the fundamental reason why orchid pests and diseases now occur severely and are difficult to control is the failure to prescribe the right medicine, mainly because diagnosis is inaccurate. The solution is to do prevention and control work yourself; for pests and diseases you do not know or are unsure about, consult experienced people nearby, and you may also consult experts engaged in this work. Be sure to diagnose accurately before it can be called prescribing the right medicine. Now many people, when discussing orchid stem rot, give the feeling of blind men touching an elephant, each blowing his own horn.
4. Apply chemicals in a timely manner
This measure mainly includes two meanings: first, control must be timely; in addition to doing routine prevention work, chemicals should be applied in the early stage of the occurrence of orchid pests and diseases; second, as mentioned earlier, for the pests and diseases that occur, especially diseases, on the premise of accurate diagnosis, select the right chemical and apply it continuously; for diseases at least 3 times (once every 7-10 days), for pests at least 2 times, to ensure a certain control efficacy. Timely application of chemicals is an effective measure to reduce the occurrence of pests and diseases and reduce losses.
5. Correctly master the use concentration of pesticides and spray evenly
At present, in orchid pest and disease control, there are two incorrect ways of using pesticides: first, using too high a concentration; for example, some people, when preventing disease, directly use a commercial chemical without diluting it in water and apply it directly to the diseased part. For orchids, this method easily causes chemical injury (direct chemical injury causes the orchid plant to wither and die; indirect chemical injury damages orchid leaves, growing points and orchid root fungi), and for pests and diseases, it easily produces resistance. The direct consequence is that when the same chemical is used later, the control efficacy is very poor or there is no efficacy at all. Many people now say thiophanate-methyl has very poor bactericidal effect; the reason is that it has been used for too long and used improperly. Second, some orchid growers are afraid that using pesticides will harm their orchids, so they use pesticides very little or at too low a concentration, failing to play a role in pest and disease control. In fact, both of these methods are unscientific. The correct method should be, according to the mechanisms of action, target pests/diseases and methods of use of various pesticides, combined with one's own or others' successful experience, to confirm that a certain chemical is effective against a certain pest or disease and causes no chemical injury, and then use it. When spraying, the front and back of leaves and the surface of the pot soil must all be sprayed to achieve relatively good control efficacy.
6. Alternate chemicals
According to which are the main pests and diseases in a certain place, choose different types of pesticides; for each pest and disease, choose more than 3 effective pesticides, rotating at least once every 1 month. Only in this way can resistance to pests and diseases be effectively reduced, control efficacy improved, and at the same time the service life of a certain particularly effective pesticide be extended. This measure should also attract the attention of the broad community of orchid enthusiasts.
7. Strengthen ventilation
The Qing Dynasty orchid grower Qu Jince of Guangdong said: In growing orchids, ventilation on all sides is the first principle; ventilation is the foremost task in growing orchids. More sun makes flowers better, more shade makes leaves better; this is said with regard to ventilation. If there is no ventilation, then with more sun they are scorched to death, and with more shade they are smothered to death; none will survive. This is the supreme discussion on ventilation in orchid growing, and it is truth. This requires us to achieve: the orchid-growing environment must be ventilated, the growing medium must be loose and air-permeable and rich in nutrients, and the orchid pot must also be air-permeable, in order to grow orchids well. Ventilation has an irreplaceable role in growing orchids well and in preventing and controlling pests and diseases, especially diseases, and every orchid grower should pay attention to it.
Why do some orchid roots grow out of the ground?
There are mainly two reasons why the root mass of orchids arches out of the ground: the orchid pot is relatively small and cannot contain them, for example if the pot has not been changed for three years; and long-term drought and lack of water, with the pot soil too full, water overflowing when watered, and the pot soil being in a water-deficient state for a long time. One can use a suitable tall orchid pot, replace the growing soil, and when watering, be sure to water until water comes out of the drainage hole at the bottom of the pot.