Troubleshooting
Lesser Begonia problems — and how to fix them
Lesser Begonia (Begonia minor) 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.
Powdery mildew
White powdery coating on upper leaf surfaces appears when air circulation is poor and humidity swings sharply; improve airflow and avoid wetting foliage.
Botrytis (grey mould)
Grey fuzzy growth on spent flowers and stems, especially in cool, damp conditions; remove faded blooms promptly and ensure good ventilation.
Vine weevil larvae
Grubs feeding on fibrous roots cause sudden wilting; check the root ball when repotting and treat with a nematode drench (Steinernema kraussei) in autumn.
Prevent lesser begonia problems before they start
Most lesser begonia issues are care-mismatch, not bad luck. Dial in the basics:
Lesser Begonia problems — FAQ
Why is my lesser begonia powdery mildew?
White powdery coating on upper leaf surfaces appears when air circulation is poor and humidity swings sharply; improve airflow and avoid wetting foliage.
Why is my lesser begonia botrytis (grey mould)?
Grey fuzzy growth on spent flowers and stems, especially in cool, damp conditions; remove faded blooms promptly and ensure good ventilation.
Why is my lesser begonia vine weevil larvae?
Grubs feeding on fibrous roots cause sudden wilting; check the root ball when repotting and treat with a nematode drench (Steinernema kraussei) in autumn.