Plant Doctor Archive

My daphne smells horrible!

Our daphne bush appears to have some sort of fungus which both smells horrible and at the same time attracts flies. The fungus is white in colour and is located at the base of stems and where new buds are forming. Can you suggest the correct treatment please?

I have spoken to two of our daphne growers and neither is aware of any white, smelly fungal disease that attracts flies, affecting daphne.

The white substance you describe sounds like mealy bug. Mealy bugs are small, slow-moving insects about 4 mm long, covered in a white mealy wax. A fringe of white filaments surround their body. Mealy bugs are prevalent in summer and autumn. They hide in flower buds and in leaf axils and can also be in the soil feeding on roots.

Mealy bugs suck plant sap from leaves and stems, causing stunted, disfigured growth. A black sooty mould can also cover the plant. This mould grows on the honey-dew excreted by mealy bugs. Ants may also be attracted to the honey-dew.

Spray with Maldison (Malathion) or Orthene mixed with Conqueror Oil. Because mealy bugs have a waxy coating, Conqueror Oil helps penetrate this, so the spray makes contact with the insect.

Some ladybirds feed on mealy bug, as well as tiny parasitic wasps from time to time which help keep populations down. If you have ladybirds present, spray with Confidor — it has a low toxicity to beneficial insects. You will still need to mix the spray with Conqueror Oil.

If you are not convinced mealy bugs are affecting your daphne, take a small sample in to your local garden centre for positive identification.

Advice by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor of Resource Management.

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