A Detailed Guide to the Methods and Techniques for Controlling Common Orchid Pests and Diseases

　　OrchidDuring cultivation, orchids are often affected byLanhua.com' target='_blank'>pests and diseases, which not only reduce their ornamental value but in severe cases can even cause death.

1. Anthracnose. This disease is the most common orchid disease, mainly affecting the leaves. In the later stage, small black dots appear on the lesions, eventually causing the diseased leaves to wither and turn yellow. The disease occurs mostly from May to June, during the plum rain season, or in years with abundant autumn rain or many typhoons from September to October. Control methods: (1) Promptly cut off diseased leaves and burn the diseased plant debris. (2) Improve the watering method, that is, slowly pour water in from the edge of the flower pot. (3) After new leaves emerge in winter, spray Bordeaux mixture (1:1:140) 1-2 times. In the early stage of the disease, spray 50% carbendazim at 500-600 times dilution. At the same time, strengthen ventilation and light transmission, and avoid spraying water on the leaf surface.

2. Leaf blight. It mainly attacks orchid leaves. In the early stage, there are small reddish-brown spots, which then rapidly expand into oval or round dark brown lesions. When there are many lesions on a leaf, the leaf tissue between the lesions loses its green color and turns yellow and dies. Control methods: (1) Remove diseased leaves and diseased plant debris and burn them in a centralized manner. (2) Pay attention to ventilation and light transmission, prevent excessive watering, and avoid directly spraying or pouring water on the plants. (3) Spray with 50% thiophanate-methyl at 600-800 times dilution. Spray about once every 10 days, and 3-4 consecutive sprays are sufficient.

3. Southern blight. One of the main diseases of Cymbidium, caused by fungi. It is prone to occur in hot and rainy seasons, often appearing in May and June, with July and August being the peak period of the disease. Control methods: (1) Promptly remove diseased leaves, diseased plants, and diseased planting holes, and sprinkle mixed lime for disinfection; before planting, drench the potting soil with 30% Tumiaoxiao water agent at 1000 times dilution. (2) In the early stage of the disease, spray 1:500 chlorothalonil on the leaf surface and use it to irrigate the roots.

4. Scale insects. Armored scales and mealybugs are the most common. The occurrence period is from April to October, and they occasionally occur in winter as well. Their reproductive capacity is extremely strong, and they can produce multiple generations in one year with overlapping generations, being most severe from May to October. Control methods: (1) When only a small number occur, they can be brushed off with a soft brush and then rinsed clean with water. (2) When there are many, spray 40% Supusha emulsifiable concentrate at 1000 times dilution during the peak hatching period. When spraying, both the front and back of the leaves must be covered. Spray continuously 3-4 times, with an interval of 5-7 days each time, and they will basically be eliminated.

5. Red spider mites have strong reproductive capacity and cause very serious damage, and are prone to occur during the high-temperature period from June to August.

Control methods: (1) If the number is small, they can be brushed off with a bristle brush or a small brush. (2) If there are many, use 40% dicofol at 1000 times dilution to kill them. (3) A traditional method is to light a mosquito coil and place it in the pot of the affected plant, then cover the pot together with a plastic bag. After fumigating for 1 hour, both eggs and adults are killed, and the plant is not affected.