JOURNAL OF AGRICULTURAL RESEARCH 
Vol. XXIII Washington, D. C., March 17, 1923 No. 11 
INFLUENCE OF SOIL TEMPERATURE AND MOISTURE 
ON THE DEVELOPMENT OF THE SEEDLING-BLIGHT 
OF WHEAT AND CORN CAUSED BY GIBBERELLA 
SAUBINETII 1 
By James G. Dickson, Associate Professor of Plant Pathology, University of Wiscon¬ 
sin, and Pathologist, Office of Cereal Investigations, Bureau of Plant Industry , United 
States Department of Agriculture 
INTRODUCTION 
Various seedling-blights, rootrots, and damping-off troubles of plants 
have long been associated with unfavorable soil and weather conditions. 
The soil-inhabiting organisms which cause this group of relatively obscure 
diseases usually become aggressive parasites only when the seedling or 
plant is weakened through its inability to react favorably to the environ¬ 
ment. Plant pathologists are continually being reminded of the import¬ 
ant correlation between climatic conditions and the occurrence of plant 
diseases. The fact is emphasized by Duggar (jo) , 3 Smith (28, p. 36 et seq .), 
and Jones (21) that the most important, most complex problems for long¬ 
time research include the critical study of the relation of environment to 
parasitism. 
From the field standpoint, this problem was well illustrated in Illinois 
during the fall of 1919. The first part of the period for sowing winter 
wheat was hot and dry, followed later by cool, wet weather. The early 
sowings of wheat were made, therefore, in a comparatively warm and dry 
soil, whereas the later sowings were made in a cool and moist soil. In 
many of the early sown fields, the seedling-blight caused by the conidial 
stage of Gibberella saubinetii (Mont.) Sacc. destroyed more than half of 
the young seedlings. Chiefly on account of these ravages, together with 
Hessian fly injury, the stand and vigor were so greatly reduced that a 
number of such early sown fields were resown the following spring. In 
contrast to this, in the fields sown late in the autumn it was almost 
impossible to find a blighted seedling, even in the worst-infested fields. 
These conditions are analogous to those affecting the development of 
cabbage yellows as noted by Gilman (u). Experiments show con¬ 
clusively that the soil organism Fusarium conglutinans Wollenw. is 
capable of inducing cabbage yellows only at soil temperatures of 17 0 C. 
or above. Tisdale found that flaxwilt (Fusarium Uni Bolley) developed 
1 Accepted for publication May io, 1922. The investigations upon which this paper is based were con¬ 
ducted cooperatively by the Office of Cereal Investigations of the Bureau of Plant Industry and the Wis¬ 
consin Agricultural Experiment Station. 
2 Reference is made by number (italic) to “ Literature cited," pp. 869-870. 
Journal of Agricultural Research, 
Washington, D. C. 
ade 
Vol. XXIII, No. 11 
Mar. 17, 1923 
Key No. G-288 
27975-23-1 
(837) 
