Learn the key points of orchid cultivation technology in southern Fujian
Du Lijun and others
Orchid is a general term for orchidaceae, but the traditional Chinese orchid refers to some orchid species with high ornamental value in the orchid family, while the national orchid refers to some terrestrial species of orchids, such as Chunlan, Hui Orchid, Jianlan, Mo Lan and Han Orchid. Guolan is one of the most culturally tasteful flowers in China, and is listed alongside "plum, bamboo, and chrysanthemum", collectively known as the "Four Gentlemen", with elegant, subtle, soft, fragrant and elegant characteristics, and has the reputation of "the fragrance of the king" [2] . With the continuous upgrading and development of orchid industrialization, the cost of orchid potted flowers has gradually decreased, and orchids have gone from being exclusive to a small number of enthusiasts to entering the homes of ordinary people. However, the planting technology of orchids is demanding, which restricts the majority of orchid people. In order to facilitate the majority of Ailan people to grow orchids and raise orchids, the key points of orchid cultivation technology are summarized as follows, in order to provide reference for the majority of growers and Ailan people.
1 Basic habits of orchids
Wild orchids are often accompanied by streams, and their growth characteristics are warm, moist and shady soil, requiring both water permeability and water retention, soil pH to 5.5~6.5 environment, the most suitable temperature is 25~28 °C, the high temperature environment in southern Fujian is often more than 38 °C, not suitable for the growth of orchids, so summer management is mainly to control high temperature, reasonable light, maintain moisture, and timely top dressing.
2 Key Management Techniques
2.1 Temperature
The optimal temperature for orchids is 25~28 °C, too high at night will cause the orchid leaves to become soft, and too low temperature will cause dark spots on the leaves. In production, shade nets, water curtains, etc. are used to control and adjust the temperature of the orchid growth environment. To promote orchid flowering, it is necessary to pay attention to adjusting the temperature difference between day and night at about 10 °C, which is conducive to nutrient accumulation and promote flower bud differentiation and thus increase the amount of flowers.
2.2 Lighting
Light is an important factor in the robustness and beauty of orchids. Experienced flower growers can judge the amount of light required from the leaf shape and leaf color, the leaves are moderately green and soft when the light is normal, the leaves are dark green and soft when the light is insufficient, and the leaf color is yellowish green when the light is too strong. In the formation stage of orchid flower buds, the varieties with dark and bright flower colors should increase the light appropriately, and the flower color is green or white, and the light intensity should be reduced when the flower buds first appear, and the light should be supplemented after the flowers.
2.3 Moisture management
The water used for orchids should be clean, pollution-free, and slightly acidic (pH 5.5~6.5). Most of the tap water is treated with bleaching powder or chlorine disinfection, and it is best to store it for 1~2 days before use, and wait for the disinfectant to be dissolved before use. There are two types of orchid water management: watering and spraying. The principle of watering is that it must be watered thoroughly, and the topsoil should not be wet and the subsoil should be dried, and half of the water should be watered. In the industry, more is the use of sprinkler irrigation technology to spray water, water spray is not only labor-saving and fine and uniform, not only can replenish water but also can increase air humidity, each spray to the degree of foliar moisture, the frequency of water replenishment is closely related to the cultivation substrate, and the substrate appears dry but not dry when the water is replenished in time. The high temperature in southern Fujian is mostly sprayed in the morning and noon, and the water should be controlled and humidified in the evening, otherwise it is easy to aggravate the occurrence of diseases.
2.4 Fertilization management
Orchid fertilization to organic fertilizer as the first choice, organic fertilizer application is more common chicken and duck manure, soybean cake, etc., to be fully decomposed and fermented before use; top dressing should pay attention to weather conditions, in sunny days and ambient temperature in 18 ~ 25 °C is the best, higher than 30 °C, lower than 10 °C and cloudy, rainy days are not suitable for fertilization, flowering, dormant period can not be fertilized. The supplement of trace elements is generally mixed with the substrate together with the base fertilizer when the substrate is renewed, and special attention should be paid to the top dressing, and the principle of a small amount of times should be strictly observed.
Newly cultivated orchids should not be fertilized within 6 months, and then a sufficient amount of organic fertilizer should be added as a base fertilizer when configuring the substrate after repotting. After that, compound fertilizer was added to promote growth, and nitrogen fertilizer was mainly nitrogen fertilizer supplemented by phosphate fertilizer at the seedling stage, and the best effect was used in the evening.
Nitrogen fertilizer can promote the growth of roots and leaves, and nitrogen deficiency will easily cause old leaves to wither and yellow, and leaves will senescence and fall off prematurely. Phosphorus fertilizer to promote flowering can also promote the stem thickness, especially suitable for the flowering and flowering period, phosphorus deficiency will cause stem and leaf growth, leaf color gray, lack of luster and other problems, and too much phosphorus fertilizer will lead to short plant type, premature development of reproductive organs, resulting in "small old trees" and so on. Potassium fertilizer is suitable for the use of medium seedling stage to promote strong seedlings, and can enhance plant resistance, thereby reducing the harm of pests and diseases; potassium deficiency will inhibit the growth of roots, resulting in small and weak roots, soft and thin leaves.
2.5 Pest and disease control
The physiological diseases in southern Fujian are mainly to prevent sunburn, and can be solved by using facility shade nets to prevent strong light exposure, and can also be solved by spraying humidification, ventilation, and strengthening water and fertilizer conditions. The main diseases of orchids are anthracnose, soft rot, white silk disease and virus diseases, and the main insect pests are scale insects, aphids, thrips, etc. Generally, pests and diseases have a process of occurrence and development, it is necessary to pay attention to the main occurrence period of pests and diseases, prevent them in advance, and clean up diseased branches, leaves, and plants in a timely manner, and completely remove the source of infection.
2.5.1 Disease control
Anthracnose, also known as black spot and brown spot, mainly harms the leaves, but also can harm the stem, the disease not only seriously hinders the growth of orchids, but also seriously affects the ornamental value, especially some leaf-based leaf art varieties. When found, the diseased leaves should be cut off immediately, burned in a concentrated manner, and the surrounding environment should be strengthened to clean up the pathogens, the management should strengthen ventilation, reduce humidity, and the drug prevention and control should be treated with 600 times of Dysen zinc frost ureanitrile or 800 times of isobromocyanuric acid, and 1 time of prevention and control every 10~15 days, 2~3 times in a row.
Soft rot mainly infects orchid varieties with thick mesophyll, the disease generally occurs on the leaves, can make the whole leaf brown, soft rot, and when the disease is severe, the whole plant dies. Spray with 1% Chunlei King copper or 500 times of agricultural streptomycin sulfate, 1 time every 10~15 days, and 3 times in a row.
Root rot, poor ventilation, high humidity, excessive wetting or water accumulation of potting soil, temperature of 18~25 °C, and non-disinfection and reuse of diseased pots and substrates are all conducive to the occurrence of diseases. Soak the plants in 0.1% potassium permanganate solution for 15 min, take out, wash and dry, replant in the updated substrate, and then use "Root Dawn" 300 times top dressing, and place it in a ventilated place to resume growth.
White silk disease, also known as white silk disease, sclerotinia sclerotinia disease. Generally, the peak incidence is from June to August, while the infection begins in April and May, and the disease occurs rapidly, resulting in the rot and death of the affected orchid plants. At the beginning of the disease, immediately change the pot to a new substrate, and spray with 500 times of pentachloronitrobenzene, or soak the diseased plants with chlorothalonil 800 times for 20 min, then wash and dry with water, and then use "Root Dawn" 300 times top dressing, and place it in other places for isolation and maintenance. There are two common kinds of virus diseases, orchid leaf virus and tooth orchid ring spot virus, which are seriously harmful, and if the diseased strains are found, they should be burned immediately, and the used orchid pots and orchid utensils should be thoroughly disinfected. Generally, the virus is treated by tissue culture to detoxify the seedling, and the seedling maintenance is controlled by 1000 times of Atelin or 1000 times of Huatuo.
2.5.2 Pest control
Scale insects are generally more harmful, such as shield scale, striped mealybug, brown round scale, red scale, etc., often clustered on branches, leaves, flowers, suck plant juice for life, and in severe cases, it will cause withering or death of the whole plant. In addition, the secretion of scale insects can also induce coal stain disease, which is extremely harmful. Emamectin benzoate perchloride + spirafen ethyl ester 800 times or trichlorfon 250 times can be used to prevent 1 time at an interval of 3~5 days and spray 2~3 times. The mite control method refers to the scale insect.
Common aphids include peach aphid, cotton aphid, etc. You can use phosphine emulsifiable concentrate and water 2000 times to spray 2~3 times.
Thrips can be sprayed and controlled alternately with thiamethoxam, acetamiprid, avermectin + acetamiprid, etc.
In addition, there are ants, snails, rats, etc., which are also very harmful to orchids, and it is necessary to pay attention to timely prevention and control.
Funds: Fujian Provincial Young and Middle-aged Teacher Education and Research Project (Science and Technology) (JAT201385).