Troubleshooting
Two-Color Cattleya problems — and how to fix them
Two-Color Cattleya (Cattleya bicolor) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Fungal spotting on leaves
Brown or black circular spots, often with yellow halos, are caused by fungal or bacterial infections encouraged by poor air circulation and water sitting on leaves. Remove affected leaves, improve airflow, and treat with a copper-based fungicide spray.
Failure to spike in autumn
Without a temperature drop of 5–8°C between day and night in late summer, the plant may not receive the thermal cue to initiate flower spikes. Opening windows on cool nights in August–September can provide the necessary stimulus.
Scale insects on pseudobulbs
Flat brown or white waxy scale insects on pseudobulbs and leaf undersides sap plant vigour. Scrub off with a toothbrush dipped in soapy water, then treat with neem oil. Isolate affected plants immediately to prevent spread.
Prevent two-color cattleya problems before they start
Most two-color cattleya issues are care-mismatch, not bad luck. Dial in the basics:
Looking for two-color cattleya in general rather than its problems? Read the full two-color cattleya care guide — light, water, soil and feeding.
Two-Color Cattleya problems — FAQ
Why is my two-color cattleya fungal spotting on leaves?
Brown or black circular spots, often with yellow halos, are caused by fungal or bacterial infections encouraged by poor air circulation and water sitting on leaves. Remove affected leaves, improve airflow, and treat with a copper-based fungicide spray.
Why is my two-color cattleya failure to spike in autumn?
Without a temperature drop of 5–8°C between day and night in late summer, the plant may not receive the thermal cue to initiate flower spikes. Opening windows on cool nights in August–September can provide the necessary stimulus.
Why is my two-color cattleya scale insects on pseudobulbs?
Flat brown or white waxy scale insects on pseudobulbs and leaf undersides sap plant vigour. Scrub off with a toothbrush dipped in soapy water, then treat with neem oil. Isolate affected plants immediately to prevent spread.