The first signs of honey fungus may be dying or stressed plants, as the fungus attacks the roots of the plants.
Other symptoms may appear as discoloured foliage, premature leaf fall, dieback, splitting bark, and weeping resin.
The fungus is spread by means of bootlace like threads that can vary in size, and are usually found in the top 150-200mm (6”-8”) of the soil.
They have a black or reddish outer layer and white or pink in the inner layer, and can spread up to 1 m (39”) a year.
Among the plants that are vulnerable are;
Apple, Apricot, Birch, Buddlea, Ceanothus, Cedar, Cherry, Cotoneaster,Crab Apple, Currant bush (ribes), Forsythia, Lilac, Leylandii (leyland cypres), Magnolia, Peach, Paeony, Plum, Privet, Rhododendron, Rose, Syringa, Viburnum, Willow (salix), Wisteria.
The obvious sign is when fungal toadstool like growths appears in late summer or autumn.
If you have reason to suspect this disease and the fungal growths are not obvious, try peeling the bark of an area of trunk/root just below soil level.
If it is present, it will appear as a creamy-white fungus with a mushroom like smell.
Fungul growths in Soil
Fungul growths on Tree
There is no effective chemical control, therefore remove and burn as much as possible of the infected root system to avoid it spreading any further.
In the event an affected tree stump cannot be physically moved, try digging a trench at least 300 mm (12”) deep around the stump and place a vertical barrier of thick polythene in it, this may reduce the spread of the fungus.