DISEASES DUE TO FUNGI 107 
are covered with a black fungal growth, are produced, 
and may cause the death of the leaves and even the stem, 
but usually only the leaves are attacked. 
Low temperatures and an excess of moisture in the 
air should be avoided. All diseased leaves should be 
removed and burned. Spraying with Bordeaux or 
Burgundy Mixture is recommended as a means of 
control. 
Powdery Mildew of the Carnation.—Occasionally this 
disease, due to a species of Ozdiwm, is found on carnations 
in this country. White, powdery patches appear on the 
leaves, also the calyx and corolla of the flower. Good 
cultural conditions are sufficient to control this disease 
in the early stages, but in severe cases dusting with 
sulphur powders or spraying with liver of sulphur may 
be necessary. Mercer (34) reports Alington, Bridesmaid, 
and British Triumph as being specially susceptible 
varieties. 
“ Die Back”’ of the Carnation.—Frequently badly cut 
stems and flower stalks do not heal but die from the cut 
end towards the main stem (Fig.36, facing p.132). Affected 
portions first turn a pale yellowish-green, then become 
yellow and die. A fungus belonging to the genus Fusarium 
is responsible for the disease, having gained entrance 
through the wound. Soft, rapid growth ; overcrowding ; 
and high temperatures favour the disease. Care should 
be taken to make clean cuts, and overhead spraying 
should be performed in the morning so that the foliage 
may be dry before night. All diseased portions should 
be cut away at a point in the healthy tissue at least 
two inches away from the apparent dead parts. The 
removed pieces should be burned immediately. 
Rust of Chrysanthemums.—This is a very common 
trouble with chrysanthemums, and is similar in nature to 
the rust of carnations. Small blisters are produced 
