Dendrobium Orchid Problems

Pests

• Many dendrobium orchid problems can be attributed to insects such as mites, thrips, aphids and scales. These pests use their long, skinny mouths to penetrate and suck the plants. Scales cause the leaves to turn yellow or to languish, while aphids cause the roots to look disfigured. Mites and thrips actually make the leaves look silver, and thrips additonally cause brown spots on flowers.

Environmental Problems

• Dendrobium orchids can suffer from issues such as sunburn, which happens when the plant is exposed to too much direct sun and results in yellow-white blotches on foliage. Dendrobiums additionally struggle to flower if the temperature around the plant is too warm, and the leaves can become a light green if the plant's soil is deficient of important nutrients such as iron. Placing the plant in a warm area that lacks humidity is a quick way to kill the plant as well.

Diseases

• Dendrobium orchid problems additionally can result from the presence of fungi. For instance, the fungus Botrytis can cause rotting flowers. Spores of the fungus Fusarium cause leaf spots and areas of atrophy. Meanwhile, reddish spots on leaves are a symptom of the Pythium fungus, while the fungus Cercopsora causes blotches on dendrobium orchid leaves. Fungi usually attack only already unhealthy plants.

Control

• The best way to protect your dendrobium orchids from insect attacks is to spray them with a systemic insecticide -- an insecticide that the plants absorbs and kills any insects that eat the plants. Examples of insecticides include those made from the chemicals carbaryl and methomyl. In addition, to keep the dendrobium orchids from rotting, apply fungicides that are made out of chemicals such as nabam or ethyl mercaptan.