1-Upper parts of the plant die. Sometimes suddenly during periods
of hot dry weather, indicating failure of the root system; sometimes more
gradually with branches dying back over several years.
2-Smaller, paler-than-average leaves.
3-Failure to flower or unusually heavy flowering followed by an
unusually heavy crop of fruit (usually just before death).
4-Premature autumn colour.
5-Cracking and bleeding of the bark at the
base of the stem.
6-If suitable conditions permit, mushrooms are produced in autumn
from infected plant material.
Dead and decaying roots, with sheets of white fungus material
(mycelium) between bark and wood, smelling strongly of mushrooms. This can
often be detected at the collar region at ground level, and rarely spreads up
the trunk under the bark for about 1m (3¼ft). This is the most characteristic
symptom to confirm diagnosis.
There are no chemicals available for
control of honey fungus. If honey fungus is confirmed, the only effective
remedy is to excavate and destroy, by burning or landfill, all of the infected
root and stump material. This will destroy the food base on which the
rhizomorphs feed and they are unable to grow in the soil when detached from
To prevent honey fungus spreading to unaffected areas, a physical
barrier such as a 45cm (18in) deep vertical strip of butyl rubber (pond lining)
or heavy duty plastic sheet buried in the soil will block the rhizomorphs. It
should protrude 2-3cm (about 1in) above soil level. Regular deep cultivation
will also break up rhizomorphs and limit spread.
Avoid the most susceptible plants and instead use plants that are
rarely recorded as being affected by honey fungus.
There are no chemical controls available.