Nov. 15,1925 Temperature for Potato Infection by Fusarium oxysporum 921 
decay, even when the soil temperature is well suited to it,* and the 
fungus is present. As has been pointed out before (<§), infection 
appears to be universal in certain sections of the West, and there 
is no reason for withdrawing this statement. Decay does not neces¬ 
sarily follow infection at once, and may not over an extended period, 
but when {he proper conditions arise epidemics develop. A low 
initial infection temperature assists the disease to appear in epidemic 
form. 
CONCLUSION 
Under approximately normal conditions and at constant tempera¬ 
tures, seed pieces from potatoes of only moderate resistance are 
infected by Fusarium oxysporum at approximately 14° C., but not at 
lower temperatures. 
LITERATURE CITED 
(1 ) Clayton, E. E. 
1920. THE RELATION OF SOIL TEMPERATURE TO THE DEVELOPMENT OF 
the tomato fusarium wilt. (Abstract) Phytopathology 10: 
63-64. 
(2) Dickson, J. G. 
1923. INFLUENCE OF SOIL TEMPERATURE AND MOISTURE ON THE DEVELOP¬ 
MENT OF THE SEEDLING-BLIGHT OF WHEAT AND CORN CAUSED 
by gibberella saubinetii. Jour. Agr. Research 23: 837-870, 
illus. 
(3) Gilman, J. C. 
1914. THE RELATION OF TEMPERATURE TO THE INFECTION OF CABBAGE 
by fusarium conglutinans wollenw. (Abstract, Phyto¬ 
pathology 4: 404. 
(4) Goss, R. W. 
1921. TEMPERATURE AND HUMIDITY STUDIES OF SOME FUSARIA ROTS OF 
the Irish potato. Jour. Agr. Research 22: 65-80, illus. 
(5) - 
1923. RELATION OF ENVIRONMENT AND OTHER FACTORS TO POTATO WILT 
caused by fusarium oxysporum. Nebr. Agr. Exp. Sta. Re¬ 
search Bui. 23, 84 p.. illus. 
(6) Johnson, J., and Hartman, R. E. ' 
1919. INFLUENCE OF SOIL ENVIRONMENT ON THE ROOTROT OF TOBACCO. 
Jour. Agr. Research 17: 41-86, illus. 
(7) Jones, L. R. 
1917. SOIL TEMPERATURES AS A FACTOR IN PHYTOPATHOLOGY. Plant 
World 20: 229-237, illus. 
(8) MacMillan, H. G. 
1919. FUSARIUM-BLIGHT OF POTATOES UNDER IRRIGATION. Jour. Agr. 
Research 16: 279-304, illus 
(9) Tisdale, W. H. 
1917. RELATION OF TEMPERATURE TO THE GROWTH AND INFECTING POWER 
of fusarium lini. Phytopathology 7: 356-360, illus. 
/ 
