Brown Spots on Cymbidium Orchids

According to Colorado State University Extension, Cymbidium orchids are native to Australia and Asia. Characterized by thick, waxy petals and flowers in varying sizes, Cymbidium orchids are susceptible to diseases that cause brown spots to develop on leaves and flowers.

Types

• Brown spots on Cymbidium orchids are often due to nutritional deficiencies. Overfertilizing orchids is a common cause of brown spots. Fungal diseases such as Anthracnose and rust cause brown spots on older orchids. Brown spot causes brown, water-soaked lesions to appear on orchid leaves.

Symptoms

• Overfertilization symptoms include stunted plant growth and brown spots on orchid leaves. Anthracnose causes brown, sunken lesions with fruiting bodies on dead leaves. Rust is characterized by orange and brown pustules on plant leaves that emit spores into the air. Brown spot causes watery spots that turn brown to black and spread rapidly. Some orchids die from severe brown spot disease.

Control

• Controlling brown spots in Cymbidium orchids is best accomplished with good cultural practices. Avoid using unsterile pruning tools, and separate any orchids with brown spots to avoid the spread of disease. Always water plants in the early morning to reduce moisture overnight. Applying fungicides often helps rid orchids of diseases that can cause spotting.