WHEAT SCAB AND CORN ROOTROT CAUSED BY GIB- 
BEREELA SAUBINETII IN RELATION TO CROP 
SUCCESSIONS 1 
By Benjamin Koehler, Assistant Pathologist, Office of Cereal Investigations, Bureau 
of Plant Industry, United States Department of Agriculture, James G. Dickson, 
Associate Professor of Plant Pathology, University of Wisconsin, and Agent, Office of 
Cereal Investigations, Bureau of Plant Industry, United States Department of Agri¬ 
culture, and James R. HolberT, Agronomist, Office of Cereal Investigations, Bureau 
of Plant Industry, United States Department of Agriculture 
INTRODUCTION 
It is a well-known fact that corn, like other field crops, can not be 
grown year after year on the same soil without harmful effects. Winter 
wheat is a crop well adapted to the corn belt. Like com, it is one of 
the most desirable crops from the standpoint of immediate financial 
returns. It, therefore, has become a common practice in the Corn Belt 
to include both corn and wheat in the rotation. In many cases wheat 
is sown directly after corn. 
In preparing com land for wheat several cultural methods are in 
common use, but very seldom is the field plowed before sowing the 
wheat. Winter wheat is often sown with a one-horse drill between the 
standing rows of com in the early fall. After the ground has become 
frozen the com is husked and the cornstalks are broken down by drag¬ 
ging a pole over them. In some localities the com is husked early, the 
cornstalks broken down and cut up with a disk harrow, and the field 
sown with winter wheat in the fall or spring wheat in the early spring. 
In other sections the com is cut and shocked, after which wheat is sown 
in the disked com stubble. Another practice in rather general use is to 
cut the com for silage and thus remove all of it, except the stubble, 
from the field before sowing the wheat. The wheat is commonly fol¬ 
lowed by a crop of oats, after which com again is planted, or the wheat 
may be followed directly by com. Although wheat is generally sown 
directly after com, yet the crop sequence often is oats after com and 
wheat after the oats. As will be pointed out later, this is a much 
more desirable crop sequence from the standpoint of the control of 
wheat scab (Fusarium blight). 
In some regions a legume, such as clover or soybeans, frequently is 
included in the rotation. In sections where the farming has become 
more intensive or where the soils are less fertile, clover is sown every 
three or four years. This not only builds up the nitrogen content of 
the soil but tends to reduce the accumulation of soil-borne parasites. 
1 Received for publication Jan. 29, 1924. The investigations upon which this paper is based were con¬ 
ducted as a cooperative project between the Office of Cereal Investigations, Bureau of Plant Industry, 
U. S. Department of Agriculture, the Wisconsin Agricultural Experiment Station, and Funk Bros. Seed 
Company, Bloomington, Ill. 
Journal of Agricultural Research, Vol. XXVII, No. n 
Washington, D. C. Mar. 15, 1924 
Key No. 0*37$ 
(861) 
85606—24-5 
