Why does your Rhododendron canescens have tiny black flies? Diagnose the cause and fix it with our step-by-step guide.
The larvae of these flies live in the organic matter of the potting medium and feed on fine root hairs, which can damage the delicate root system of an Oakleaf Azalea. The presence of adult black flies is most often a sign that the soil remains consistently moist for too long.
Similar to fungus gnats, these flies thrive in the acidic, highly organic soils preferred by Rhododendron canescens. They breed in decaying leaf litter or mulch layers that stay perpetually wet.
While not the cause of the flies themselves, the presence of flies often indicates an environment conducive to Phytophthora or Pythium. These pathogens thrive in the same waterlogged conditions that attract fungus gnats.
Your plant might also be experiencing one of these issues:
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