petal blight on Phalaenopsis
Quick answer
If your Phalaenopsis has petal blight, the most likely cause is: Petal blight on Phalaenopsis is a fungal disease that produces dark brown or black spots, often with pinkish margins, on the open petals of autumn-flowering plants; it is favoured by high night-time humidity combined with cool greenhouse temperatures that allow the fungus to germinate on damp petal tissue and spread from one bloom to the next.
Start here:
- 1. Remove every infected flower as soon as the dark brown or black spots are noticed, bagging and disposing of the blooms rather than leaving them on the plant or the bench so the fungal spores cannot reinfect adjacent open flowers.
- 2. Drop night-time humidity below the level where condensation forms on the petals by improving air movement and avoiding misting or watering late in the day during the cooler autumn flowering window.
Why Phalaenopsis gets petal blight
Phalaenopsis
Petal blight on Phalaenopsis is a fungal disease that produces dark brown or black spots, often with pinkish margins, on the open petals of autumn-flowering plants; it is favoured by high night-time humidity combined with cool greenhouse temperatures that allow the fungus to germinate on damp petal tissue and spread from one bloom to the next.
How to reverse petal blight on Phalaenopsis
- 1
Remove every infected flower as soon as the dark brown or black spots are noticed, bagging and disposing of the blooms rather than leaving them on the plant or the bench so the fungal spores cannot reinfect adjacent open flowers.
- 2
Drop night-time humidity below the level where condensation forms on the petals by improving air movement and avoiding misting or watering late in the day during the cooler autumn flowering window.
- 3
In a cool greenhouse, supply gentle additional warmth during autumn so the night air does not fall into the temperature band that lets the petal blight fungus establish on damp petal tissue.
Keep petal blight off this Phalaenopsis
Keep the air around flowering Phalaenopsis moving and on the dry side at night during autumn, and supply additional warmth in cool situations, since petal blight needs damp petals at cool temperatures to infect Phalaenopsis blooms.