Orchid disease prevention focuses on three seasons: seize the timing to reduce disease

Orchid disease prevention focuses on three seasons Orchids fall ill mostly because the growing medium is wet, stuffy and unclean, or overly dry. When the medium is wet, stuffy and unclean, air is pushed out, pathogens multiply in large numbers, orchid roots are damaged, and various diseases arise from this, harming the orchid plant. When the medium is too dry, the fleshy roots suffer physiological dehydration and shrivel, losing their conducting ability, so water and nutrients cannot be supplied in time, and orchid leaves become rough with scorched tips. An orchid struggling on the edge of life and death will, to stay alive, open its stomata wide to absorb moisture from the air, and various pathogens take advantage of this opening, with disease following soon after. In addition, if the concentration of fertilizer or pesticide is too high, exceeding the cell concentration of the orchid plant, it causes reverse osmosis and dehydrates the orchid, which likewise triggers disease. To prevent orchid diseases, besides measures such as keeping the environment clean and moist, providing ventilation, watering and fertilizing lightly and evenly, applying pesticides at the right time and in the right amount, keeping the medium clean and permeable, and providing suitable light, it is even more important to grasp the main contradiction according to the actual conditions of each place and carry out targeted prevention and control. The plum rain season has a warm climate and high air humidity; it is the golden season for orchid growth during the year, and also the peak period for various diseases. When the temperature is around 22 degrees, various diseases are most likely to occur. To avoid disease, two points must be noted in this season: first, control watering; second, apply pesticide in time. In autumn, the climate turns from hot to cool, and it is another growing season for orchids. Autumn air is relatively dry, and orchids easily lose water, so attention must be paid to timely watering. At the same time, after passing through the hot summer, orchids have consumed a great deal and their resistance is relatively weakened, so in early autumn phosphorus and potassium fertilizer should be supplemented in time to strengthen disease resistance. Autumn is also a peak period for various diseases, so pesticide must be applied in time. During the period from one week before the Start of Autumn to Cold Dew, pesticide must be applied to the orchids once every ten days, to ensure that the orchids can grow healthily throughout the whole autumn and until the spring of the following year. In winter, orchids need to be kept warm indoors; some people build a sealed plastic shed on an indoor balcony or under eaves that are sheltered from wind and face the sun, and place the potted orchids inside to receive sunlight. Sometimes the temperature inside the shed rises to over twenty degrees, letting them be steamed stuffily, and disease spots occur from time to time. Once discovered, applying pesticide liquid to the leaf surface is of no avail. With sealed plastic sheds, including glass sheds, one must always be careful; when the temperature inside the shed exceeds ten degrees, windows must be opened in time and the film lifted to let the orchids ventilate. On days with high temperature and strong sunlight, appropriate shading is also necessary; never expose them to blazing sun and steaming. The late orchid-growing expert Mr. Wang Shuping of Yuyao emphatically pointed this out in his article "Fifty Years of Orchid Growing Experience," saying that orchid growers often overlook this point, so it must be specially reminded. In summary, on the basis that other management measures for growing orchids can also be kept up in time, controlling watering and applying pesticide in time during the plum rain season; watering in time, supplementing phosphorus and potassium, and applying pesticide at the right time in autumn; and avoiding blazing sun and steaming in winter are the keys to disease prevention and treatment in different seasons. Grasping these three key seasons when disease is likely to occur will make the disease prevention effect very different. As for the high-temperature season, because the temperature is too high, disease is not obvious, and doing a good job of ventilation and shading is enough. In addition, the layout and treatment of the medium also require much attention. In the orchid pot, the medium should be coarse at the bottom and fine at the top, with clear layers, so that water is received evenly. It is best not to mix media of different coarseness together for planting orchids, lest when watering, blocked by the large particles of medium, the water distribution be uneven, causing orchid roots that receive excessive water to rot and orchid roots that receive insufficient water to shrivel. Before planting orchids, the medium must be disinfected; it can be sun-dried, steam-sterilized, or stir-fried in a pan. The purpose is to kill pathogens and eliminate the disease sources inherent in the medium.