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?
have spoken to two of our daphne growers and neither is aware of
any white, smelly fungal disease that attracts flies, affecting
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.
by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor
of Resource Management.
with permission from NZOOM Home and Garden content,
from the previous
The views expressed here are not necessarily those of the RNZIH