News and Notes 
279 
Bulletin No. 281 of the Bureau of Plant Industry of the United 
States Department of Agriculture contains a discussion by L. L. 
Harter and Ethel C. Field on a dry rot of sweet potatoes caused 
by a fungus which has been named by them DiaportJic Batatatis. 
The fungus is thought to represent the perfect stage of Phoma 
Batatae Ellis and Halsted. The fungus is not a vigorous parasite 
and the disease is principally a storage trouble and is characterized 
by a drying and shriveling of the potatoes with the pycnidia form- 
ing on the surface. In the greenhouse the pycnidia also occur on 
the leaves and stems as well as the roots of the infected plants. 
It is suggested, in order to prevent the spread of the trouble, 
that diseased potatoes should be cooked before being fed to stock. 
Diseased potatoes should not be used for fertilizer. Steriliza- 
tion of seed bed is also suggested. No experiments were con- 
ducted in controlling the disease. 
In farmers’ bulletin No. 544, W. A. Orton summarizes the 
principal potato-tuber diseases and discusses the best means of 
eliminating or controlling them and thereby materially increasing 
the potato yield. It is claimed that the potato yield is only about 
one half what it might reasonably be expected to be per acre. 
In Science for July ii an article appears by Professor H. L. 
Bolley, of the North Dakota Agricultural College, on the com- 
plexity of the microorganic population of the soil. The article is 
in part an answer to one by E. J. Russell of Rothamsted Experi- 
ment Station which appeared in Science for April 4. 
Professor Bolley agrees with Russell in many of his statements 
but takes exception to assuming that protozoa are the principal 
crop-limiting factor in deteriorated soils. Bolley claims that if 
we have purified seedlings placed in a purified soil they show no 
tendency to deteriorate. He also claims that species of fungi such 
as Fnsariiim, Alternaria, H elminthosporium, etc., in the soil are 
the real crop-limiting factors, aside from mineral elements and 
atmosphere, and that crop deterioration is probably a problem of 
crop sanitation as involved in infectious diseases. According to 
this theory sterilization is beneficial in that it destroys harmful 
fungi, the chief crop-limiting factors. 
