Troubleshooting
Modest Cape Primrose problems — and how to fix them
Modest Cape Primrose (Streptocarpus modestus) is generally low-drama, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Fungus gnats
Larvae of fungus gnats (Bradysia spp.) tunnel through the fine compost and damage roots, causing wilting and yellowing; adults are attracted by consistently moist surfaces. Allow the compost surface to dry slightly between waterings and apply a nematode drench (Steinernema feltiae) to control larvae.
Leaf spot (Cylindrocladium / Cercospora spp.)
Circular brown spots with pale halos appear on leaves in warm, humid conditions with poor air movement; the small, closely spaced rosette leaves are particularly susceptible. Remove badly spotted leaves, increase ventilation, and avoid overhead watering.
Prevent modest cape primrose problems before they start
Most modest cape primrose issues are care-mismatch, not bad luck. Dial in the basics:
Modest Cape Primrose problems — FAQ
Why is my modest cape primrose fungus gnats?
Larvae of fungus gnats (Bradysia spp.) tunnel through the fine compost and damage roots, causing wilting and yellowing; adults are attracted by consistently moist surfaces. Allow the compost surface to dry slightly between waterings and apply a nematode drench (Steinernema feltiae) to control larvae.
Why is my modest cape primrose leaf spot (cylindrocladium / cercospora spp.)?
Circular brown spots with pale halos appear on leaves in warm, humid conditions with poor air movement; the small, closely spaced rosette leaves are particularly susceptible. Remove badly spotted leaves, increase ventilation, and avoid overhead watering.