Red streaks and patches are bad news for bulbs – caused by fungus
“What pretty leaf variegation!” This was my first thought when my five Amaryllis bulbs started coming into leaf.
However, my ignorance proved my undoing. The ‘variegation’ turned out to be a fungal disease called red blotch (it’s also known as leaf scorch or red fire).
The fungus Stagonospora curtisii is the culprit and Amaryllis are especially prone to it, especially in cool, damp conditions – that will be because of last summer they spent outdoors.
Bright red patches form on all parts of the amaryllis, enlarging into cankers which become sunken and moist.
Mine hasn’t reached that point yet, but growth is weak and only one has shown signs of flowering. The leaves are distorted and flower stalks may snap easily.
How to get rid of red blotch
- As the disease is difficult to control completely, the standard advice is to destroy the bulbs, get rid of all affected soil and thoroughly wash pots to prevent cross infection.
- You can try digging up dormant bulbs, removing diseased parts, then soak them in a 1% bleach/water or 1% hydrogen peroxide/water solution for an hour. Dry and store after treatment.
- If the bulbs are growing, try replanting into clean soil and apply a systemic copper-based fungicide, until the bulbs go dormant. However, I don’t like using unnecessary chemicals, so the worst affected will have to go.
- However, I’m going to try natural anti-fungals on those I can save, starting with Aloe vera. As an experiment, I stripped away as much affected tissue as possible and got rid of the top layer of soil. I rubbed all visible surfaces with the flesh of an Aloe vera leaf. I’ll report back on how it goes.
- Garlic, cinnamon, pepper, thyme, lemon and mint all have anti-fungal properties to a greater or lesser extent.
How to avoid red blotch
- Buy healthy bulbs from a reputable supplier.
- Inspect bulbs before buying and reject those with cankers.
- Plant bulbs in a clean pot with sterile, new compost.
- Wipe tools, pots and canes used on infected plants with alcohol.