Dahlia Yellow Flower Black Leaves. Aphids carry this virus and spread it when they drink the sap of new plants. Yellow streaks are seen along the midrib or veins.
Stems may turn yellow display brown or black streaks or simply wilt. Leaf margins may turn brown or appear scorched. The silver on black combination is very striking.
This deadly disease causes stems to become mushy and rotted.
Stem interior with brown or black streaks Wilt Leaves with irregular holes and pieces eaten away with slime trails present on or near plants Slugs and Snails. The single flowers up to 3 in. Try some yellow flowered Dahlia Farfugium Coreopsis or Helianthus against a black elephant ear and youll see what we mean. The sooty mold interferes with photosynthesis and by that stage the leaves on your dahlia will be turning yellow.