What is wrong with my Dendrobium orchid?

Do the Dendrobium plants have wilted leaves and dried stems that don’t respond to watering?

Do the leaves of the Dendrobium have spots or blotches?

Are there any small translucent spots on the leaves that later turn black?

Are there any water-soaked, brown lesions on the stems and petioles?

Are the flowers covered with gray mold, leaves may be blotched or discolored?

Are there any yellow and wilting leaves, brown streaks appear on a lower surface of leaves, the growth is stunted?

Do the leaves have any small circular or irregularly shaped dry spots which are gray to straw in color?

Are the leaves mottled with yellow, young growth may be narrow and twisted?

Are the leaves curled and distorted?

These symptoms in Dendrobium could indicate a fungal disease - Rhizoctonia Root Rot. Improve soil drainage by working some compost into the top ten inches. Discard all infected plants. Do not overwater plants. Pot in the pasteurized soil mix. Apply a copper-based fungicide to protect plants.

Your Dendrobium plant is suffering from a fungal leaf spot. These can come from a number of fungus diseases, causing spots to occur on foliage. Spots may enlarge rapidly, especially in wet weather. Destroy infected leaves or plants. Spray plants with sulfur to prevent the disease from spreading, especially if the weather is wet. Spray between rains. Prevent problems by thinning plants to provide good air circulation.

Bacterial leaf spot causes circular translucent spots scattered over the leaf surface between the veins. These spots turn brownish-black and may spread to form large patches of dead tissue. To prevent the spread of this disease, avoid working around wet plants. Remove and destroy affected parts. Spray Bordeaux mix on remaining plants.

Bacterial soft rot is caused by a bacterium that is common in most soils, particularly if the area is frequently planted with susceptible crops. Remove and destroy infected plants. Avoid planting in poorly draining soil. Rotate crops with corn, small grains, or grasses where possible. Plant saffron varieties that are resistant to the disease.

Gray mold on flowers is probably caused by fungal disease - Botrytis blight. You can prevent Botrytis blight disease by planting in areas with good air circulation. Water plants sparsely. Severely infected plants should be removed. Spray weekly with a copper fungicide until the disease is under control.

Fusarium wilt is a fungal disease that causes these symptoms. High soil temperatures favor the disease emergence. Use only disease-free seeds. Treat seeds with hot water to kill fungi before planting. Destroy affected plants at the first sign of fusarium. Rotate crops to non-susceptible species.

These symptoms indicate a fungal disease - Anthracnose. Keep plants dry when watering to prevent spread. Spray plants with copper if you have had problems in the past. Bordeaux mixture can also help to protect the plant from the disease.

Leaves mottled with yellow usually indicate a Tobacco mosaic virus. There is no cure for viral diseases, remove and destroy infected plants. Presoak seed in 10 percent bleach solution before planting to prevent problems. Control aphids as they are the most likely carriers of the tobacco mosaic virus.

Distorted and curled leaves in Dendrobium are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

If the leaves are covered with white, cottony clusters the culprits are mealybugs. These tiny insects are covered with a fluffy white coating. They feed by sucking plants sap. They produce the sticky substance honeydew which makes leaves sticky. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.