Dendrobium Leaf Problems: Identifying and Treating Dry Patches

Understanding Dendrobium Leaf Damage

A Dendrobium owner in Australia noticed a dry, thumb-sized patch on a leaf about an inch from the stem. The plant had recently been treated for a fungal infection, and a black spot was removed from another leaf. The patch continued to grow daily, causing concern.

Possible Causes

Several factors could cause such symptoms. Sunburn is a common suspect, but the pattern suggests other issues. Insect damage typically appears sporadically, not as a single expanding spot. Bacterial infections usually look watery, not dry. A strong candidate is anthracnose, a fungal disease that thrives in warm, humid conditions with poor air circulation and low light. Anthracnose often starts as a reddish-brown spot that darkens over time.

Recommended Treatment

If anthracnose is suspected, remove the entire affected leaf immediately and dispose of it to prevent spore spread. Apply a copper-based fungicide to the whole plant. Consult a local Australian garden center for approved products. Improve air movement, reduce leaf wetness, and ensure adequate light to prevent recurrence.

Monitor the plant closely; new growth should appear healthy if the infection is contained.