Blog: Red streaks and patches – bad news for Hippeastrum bulbs – caused by fungus
The Amaryllis disease red blotch can be mistaken for pretty variegation – that’s what I did. Sadly, it’s a fungal disease which is also known as leaf scorch or red fire, first spotted when my five bulbs started coming into leaf.
The fungus Stagonospora curtisii is the culprit, and Amaryllis are especially prone to it, especially in cool, damp conditions – that will be because they spent the summer 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 distort, and the flower stalks snap easily.
How to get rid of Amaryllis red blotch disease
- As the disease is difficult to control completely, the standard advice is to destroy the bulbs. Dispose of all affected soil and thoroughly wash pots to prevent cross-infection.
- You can try digging up dormant bulbs, removing diseased parts, then soaking them in a 1 per cent bleach/water or 1 per cent hydrogen peroxide/water solution for an hour. Dry and store after treatment.
- If the bulbs are growing, try replanting them into clean soil and applying a systemic copper-based fungicide until the bulbs go dormant. However, I don’t like using unnecessary chemicals, so not an alternative for me.
- 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. The result? Amaryllis red blotch didn’t get any worse, but it didn’t get any better!
- Garlic, cinnamon, pepper, thyme, lemon and mint all have anti-fungal properties to a greater or lesser extent.
How to avoid Amaryllis disease red blotch
- Buy healthy bulbs from a reputable supplier. The RHS has a lovely selection.
- 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.
Can you provide an update on how your aloe treatment worked? I’m battling red blotch with some amaryllis that I’m reluctant to throw. I’m trying cinnamon at the moment, as my aloe is a bit too small to keep chopping bits off (it has great sentimental value so I don’t want to lose it!), but if aloe works, I’ll buy another one purely to use as amaryllis medicine!
Hi there… The aloe treatment had some effect on the less affected plants but the worst couple (which were pretty bad) I ended up just getting rid of but that may have been my impatience! Give it a go and beef the bulb up with food so it can fight back. Hope that helps. All the best, Mandy