DISEASES DUE TO FUNGI 105 
entire plant. Affected leaves turn yellow round the 
diseased spots and ultimately curl and die. While few 
glasshouses are entirely free from rust it only becomes a 
serious trouble when the temperature is excessively high 
and the plants are over-watered. When the leaves at 
the base of the plant are continually moist ideal condi- 
tions for spreading the disease are produced. Thus 
Fig. 27. (a) Rust of the carnation, (b) uredo-spore, (c) teleuto-spore, (d) spore mass, 
(e) stigmonose of the carnation. 
where rust is prevalent it is advisable to keep the lower 
foliage off the ground by wire netting supports, bent in 
the shape of an inverted V, placed between the rows. 
Rust is spread each year by means of cuttings taken 
from diseased plants, and in consequence it is necessary 
to propagate from healthy plants only. Sponging the 
leaves with a solution of potassium permanganate has 
been recommended as a means of checking the disease, 
while spraying with liver of sulphur and flour paste solu- 
tion has proved useful in severe cases. Careful attention 
