DISEASES DUE TO FUNGI 91 
defoliation, and regulation of the atmospheric humidity 
by efficient ventilation. When removing side shoots and 
unwanted leaves, the cuts should be clean, and made 
close to the main stem, when they will rapidly heal over. 
If stumps are left, these do not heal over, but shrivel and 
die, affording suitable places of entrance to the fungus. 
When the fruit has been picked from the lower trusses 
the plants should be defoliated from the base to the 
lowest unpicked truss to allow the air to circulate freely 
through the plants. In bad cases it may be necessary 
to spray the stems with a 2 per cent solution of calcium 
bisulphite to destroy the spores of the fungus and so 
lessen the risk of infection. Carnations, chrysanthemums, 
and roses under glass are subject to this disease, the 
conditions of infection and control being the same as in 
the case of the tomato. 
Stem Canker of the Rose.—The symptoms of this 
disease are large, cankered wounds frequently found on 
rose stems. The lesions are brown in the centre, with a 
black border, usually surrounded by a reddish zone. 
The disease, caused by Coniothyrium Fuckelii Sacc., first 
appears as small, reddish patches on the young wood. 
Later, cracks develop at the infected points, and increase 
in size, becoming extended and distorted by the produc- 
tion of callus until the typical canker is produced. 
Examination with a lens readily shows the presence of 
minute black bodies scattered over the surface of the 
canker; these are the pycnidia or fruit bodies of the 
fungus. Infection takes place on the tender shoots or 
through wounds made in older parts of the plant. All 
infected parts should be removed and burnt at once if 
the disease is to ke controlled. 
Rose Graft Disease.—Recently a rose graft disease, 
caused by Coniothyrium rosarium, has been described by 
Vogel (51) in America. The disease attacks the scion at 
the union, and speedily causes wilt and death. The 
