vit] Smuts 77 
remains but the main stalk or rachis of the ear which 
usually has a certain amount of smut adhering to it. 
Some of the spores reach the stigmas of wheat flowers. 
Here a germ tube is produced which grows through the 
style much in the same way as the tube from a pollen 
grain. Eventually the tube reaches the developing 
seed. The grain so infected ripens normally and can 
in no way be distinguished from a non-infected grain. 
When these grains containing the smut mycelium are 
sown the ears of the plants which they produce become 
smutted and spores are blown about to infect fresh 
plants. The mycelium maintains its position at the 
growing point as described above. The loose smut 
of barley has a similar life history. The weather 
plays a big part in the prevalence of the loose smuts. 
If at the time the spores are forming there is a lot 
of rain the majority of them are washed to the ground, 
with the result that fewer grains become infected and 
less smut is produced in the following season. 
Remedial Measures. 
In the life history of the smuts we have seen that 
they may be divided into two classes: (a) those which 
infect at the seedling stage; (b) those which infect at 
the flowering stage. The treatment will therefore be 
different in the case of these two groups. 
In both the disease is spread from smutted ears, 
and consequently in choosing seed corn we shall do 
well to obtain it, if possible, from fields which contain 
no smut. This does not ensure our crop from attack 
as the smut may have blown from neighbouring 
fields, but seed from a clean field usually produces 
considerably less smutted ears than that from a 
