Yellow and Black Spots on Oncidium: Fungal Prevention

Grace's Oncidium had spotty yellow leaves with black spots underneath, grown near a wood stove with twice-daily misting. Expert: common Oncidium fungus from mist settling on leaves. No cure for existing spots. Copper-based fungicide mist prevents spread to new growth. Reduce misting to morning only; use fan to dry leaves. Repot in fresh commercial mix with drainage when new growth starts.