Honeydew – sugar-rich sticky liquid secreted by aphids.

An ant milks aphids, as a farmer milks cows., photo: Dawidi - CC BY 2.5

Honeydew – sugar-rich sticky liquid secreted by aphids. Aphids suck plant sap from leaves; some of these sugars are consumed for energy and the rest is excreted. The excess liquid sugar remains on the plant and often ends up on the ground.
Ants keep aphids like farmers keep cows. The ants protect the aphids from enemies such as the ladybird and sometimes make underground “stables” where the aphids are kept.
Honeydew is rich in liquid sugars.
The sugars can mold and become covered with a layer of black fungus: sooty mold.

Where to find

  • Common on deciduous trees, especially:
  • Linden (Tilia) – European species
  • Lime tree (Tilia) – UK, Ireland
  • Basswood (Tilia) – North American species
  • Oak
  • Ivy (Hedera)
  • Fruit trees


Difficult to control; sugars secreted by aphids are the cause. Removing the aphids stops honeydew production. Honeydew is not easy to remove from the leaves.


Provide a bird-friendly environment: birds eat aphids. Keep plants in good condition.

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