318 Annual Report for 1908 of the Consulting Botanist. 
injuries due to the common turnip fly had offered suitable 
places for the growth of the fungus at the base or the middle 
of the root. A photograph is reproduced of a longitudinal 
section of a diseased root showing the extent of the injury 
(see Fig. 5), and a small portion, A, from the edge of this 
section has been considerably magnified to exhibit the 
cavities formed by the colonies of bacteria (Fig. 6). As 
a result of the wet weather following a period of drought, 
the turnip bulbs grew in circumference, the portions of the 
bark killed by the fungus failed to expand like the healthy 
portions, and fissures resulted. These fissures, of course, were 
soon infested with bacteria, and though there were many 
distinct forms present, one was very predominant. This was 
separated and stained and compared with a slide, kept for 
reference, of the bacterial disease of turnips, described in the 
Report for 1900. They were found to be the same kind. There 
is sufficient other evidence to justify the view that the bacteria 
gained access to the interior through the cracks in the skin of 
the turnips. The pinkish colour of the slimy mass was due to 
a small yeast fungus which would naturally appear in a juice 
rich in starch and sugar, as the sap of the swede is. This 
yeast caused rapid fermentation, and on account of the pro- 
duction of gases gave off the foul smell from the roots. The 
attack by the Phoma is the first stage in the injury. The 
fungus appears in dry weather and on dry land. Steps should 
be taken to present the recurrence of the disease where it has 
once made its appearance. The diseased roots should be 
removed from the field and destroyed by fire or treated with 
quicklime to kill the spores of the fungus. The infested field 
should have scattered over it gas lime to the amount of two to 
three tons to the acre. The fungus may perhaps attack other 
root crops, so that it would be well to avoid the culture of 
roots for some seasons. 
Appearance of a New Potato Pest. 
Plants that are universally reproduced by vegetative means, 
i.e., by cuttings or tubers, like the potato, are thought to be 
exposed to some more or less pronounced degree of degenera- 
tion. It is for this reason that a change of seed is recommended 
to secure new vigour. Old varieties grown continually on the 
same land have frequently failed to produce as satisfactory 
crops as the same varieties grown elsewhere. The degenerative 
symptoms are indicated by premature ripening, yellowing of 
the leaves, and few and small tubers. On the other hand, no 
variety of potato is entirely free from disease. This has been 
recently proved on the Continent by Graf Arnim-Schlagenthin, 
who experimented with 400 distinct varieties, and found 
