Plant Diseases 
321 
into growth later on and infect any healthy tubers in its 
neighbourhood. The diseased tubers must not be given 
to pigs or cattle, for some may be left among the farm 
manure, and be taken out into the garden or field, there 
to set up the disease again. They should, however, be 
carefully taken away, the worst ones burned, or mixed with 
quicklime, and the others boiled. These latter may then 
be given to the animals. There will then be no fear of 
the disease finding its way back from this source. The 
whole of the tubers should be carefully looked over, espe- 
cially those which are put into a clamp and kept for a 
considerable time, because if the weather is mild the 
disease in the tubers may start into growth, and, having 
no outlet in stem or leaf, the whole tuber will be destroyed. 
The disease will then make its way into others and destroy 
them also; then when the clamp is opened a great portion 
of the tubers will be found to be destroyed. This would 
probably not have happened had the potatoes been care- 
fully examined before storing. 
The method adopted by most growers of storing their 
potatoes in boxes placed in cool sheds, effectually prevents 
any chance of the temperature rising, and so starting the 
mycelium into growth during this period. Even then care 
should be taken not to include any diseased tubers, as 
the disease will lie quite dormant while they are in the 
boxes, but as soon as they are planted the stems and 
leaves will become infected, spores will be produced, and 
the whole crop may suffer. 
Some seasons are more favourable than others to the 
spread of this disease. In damp seasons it spreads most 
rapidly. This is not to be wondered at when we know 
(C525) ' 22 
