436 
of the straw be examined with a pocket-lens, numerous minute, 
black, wart-like bodies will be seen, more especially on the inner 
side of: the sheaths encircling the base of the stem. These are the 
fruits of the fungus causing the disease. This phase of the disease 
often occurs in more or less definite patches in the field, which show 
conspicuously at a distance owing to their whitish or bleached 
appearance, while the healthy part of the crop is still green. 
In the condition known as “ Take-all,” the plants are attacked 
seriously at an early stage of growth and become yellow, and often 
die before the stem is formed, or at all events before the ear escapes 
from its sheath. § in the case of “ White-heads” the disease 
of such stunted plants may be found. If carefully examined the base 
of the plant will be found to present a somewhat blackened nance. 
dense formation of root-hairs. In many instances a second lot of 
roots may be formed higher up on the stem of diseased plants, but 
these in turn are attacked by the fungus, and the plant ultimately 
succumbs, ‘ White-heads ” and “ Take-all” were at one time con- 
Infection experiments have proved that this fungus is the direct 
cause of the disease. 
he disease is probably far more prevalent in this country than is 
generally suspected. Material sent to Kew from time to time, for 
examination, while highly suggestive of this disease, is invariably 
cut off at some distance from the ground, consequently that portion 
of the plant that would afford actual proof of the nature of the 
disease-is absent, and a request for a secend batch including the 
root, is but rarely responded to. The fungus was first observed in 
England by Worthington G. Smith in 1884,* and named “Straw 
blight.” It is stated that the loss occasioned ranges from one-half 
to one-fiftieth of the crop. The disease is also well known in 
The spores of the fungus are liberated during the winter or early 
spring, and remain in the soil until the required amount of moisture 
and temperature induces germination. According to Mangin,f the 
Spores on germination either directly give origin to a number 0 
colourless, minute, sickle-shaped, secondary spores, or a slender 
germ-tube is first formed, which bears a cluster of the secondary 
Spores at its tip. From these secondary spores on germination a 
very delicate germ-tube arises, which enters the wheat plant 
* Diseases of Field and Garden Crops, p. 6 : 
p. 69. s 
tT Compt. Rend., 127, p. 286 ; Bull. Soc. Myc, France, 15, p. 210. 
