Detailed Guide to Pest and Disease Control Methods for Cymbidium sinense

(1) Disinfection agents for tools, supplies, and seedlings. 70% alcohol, bleaching powder, Baidusha, potassium permanganate. (2) Fungicides. Thiophanate, fenaminosulf, mancozeb, chlorothalonil, Bordeaux mixture, miebingwei. (3) Bactericides. Bactericide, amobam, streptomycin. (4) Insecticides. Pyrethroids, omethoate, derris extract, puchijing, supusha. All the pesticides listed above should be used strictly according to the instructions. If the instructions do not list a dilution rate for use onCymbidium sinense, the dilution rate for general flowers or vegetables may be used for mixing with water, but it should be somewhat more dilute. (5) Pruning and repotting. When old leaves turn yellow or dry up, they should be cut off or removed to improve ventilation. Severely diseased leaves should also be cut off promptly to prevent contagion. When cutting off diseased leaves, the scissors must be disinfected after cutting before cutting healthy leaves, to avoid contagion. After each flowering, some flowers will have faded within a few days; the entire flower stalk should be cut off promptly to avoid consuming nutrients and affecting the sprouting of new shoots and the growth of new flower stalks. Repotting is usually carried out together with division, generally once every two years. The best time for repotting is during the dormant period after flowering, though it can also be done in spring or autumn. After tipping the orchid plant out, carefully shake off the old potting medium, rinse clean with water, then cut off old and damaged orchid roots. Clear the connecting points or connecting bands between the plants, and after examining them clearly, cut them apart with scissors to avoid damaging healthy roots. The cut surfaces can be coated with plant ash or sulfur powder to prevent infection. Division can sometimes also be done by grasping one orchid head in each hand and then rotating and twisting to separate them. The above division work requires sharp eyes and deft hands to prevent damage to the roots on the orchid heads, the initial growing points of shoots and flower stalks, and the small buds and small flower scapes. After division, place them in a cool, shaded spot to dry, and once the roots are soft, plant them according to the above method. (Yan Xueliang)