CORN-ROOTROT AND WHEATSCAB 
[PRELIMINARY PAPER) 
By G. N. Hoffer, A. G. Johnson, and D. Atanasoff 
Cereal Investigations , Bureau of Plant Industry , United States Department of Agriculture 
In the progress of the investigations of rots of the root, stalk, and ear of 
Indian corn (Zea mays) being conducted by one of the authors (Hoffer) 
certain things have developed which have such an important bearing on 
certain phases of the wheatscab problem which is being investigated by 
the other authors that it has seemed desirable to publish a preliminary 
statement. 
Field observations have shown a conspicuously greater abundance of 
wheatscab in fields where the wheat (Tritieum aestivum) was grown imme¬ 
diately following com that was infected with the Fusarium-rot of the 
root and stalk. This was especially true in Shelby County, Indiana, where 
wheat, according to a common practice, was sown in standing corn. 
A similar condition was also noted in Dane County, Wisconsin, this 
summer, where spring wheat was grown immediately following a corn 
crop. Both in Indiana and in Wisconsin under these conditions abundant 
development of perithecia of Gibberella spp. was found on the old corn¬ 
stalks remaining in these fields. These perithecia were mature and well 
filled with viable ascospores at the time when the wheat, in all cases 
observed, was in head. 
Water suspensions of these ascospores both from Indiana and from 
Wisconsin cornstalks gave positive results when used as inocula on wheat 
heads. The inocula were applied by means of an atomizer spray. In 
some cases the heads were subsequently covered with glassine bags for 
three days, and in other cases no coverings were used. In all cases posi¬ 
tive infections were obtained, while the controls sprayed with sterile 
water and similarly treated remained unaffected. The appearance of 
the infected heads thus artificially inoculated was identical with that 
of wheat heads naturally infected with scab. 
Cultures from Gibberella spp. on old cornstalks have also proved 
virulently parasitic on the roots of com plants grown both in large, 
sterile agar tubes and in sterilized pots of soil. 
Similar results on both wheat and com have been obtained by using 
cultures from naturally infected wheat heads. 
The organisms from both sources have also been found to be similar 
morphologically. In view of the facts developed by this evidence, it 
seems certain that these are intercrop parasites which are of great impor- 
Joumal of Agricultural Research, Vol. XIV, No. 13 
Washington, D. C. Sept. 83,1918 
ps Key No. G-xs 7 
(6u) 
