UNITED STATES DEPARTMENT OF AGRICULTURE 
In Cooperation with the 
Wisconsin and Illinois Agricultural Experiment Stations 
DEPARTMENT BULLETIN No. 1361 
Washington, D. C. 
September, 1925 
A MOSAIC DISEASE OF WINTER WHEAT AND WINTER RYE 
By Harold H. McKinney, Associate Pathologist, Office of Cereal Investigations, 
Bureau of Plant Industry 
CONTENTS 
rage 
Introduction 1 
Distribution and importance 1 
Description of wheat and rye mosaic. 2 
A leaf mottling not mosaic 4 
Page 
Inoculation studies 5 
The mosaic causal agent exists in 
certain soils 8 
Control measures 10 
INTRODUCTION 
This mosaic disease of winter wheat, referred to previously by the 
writer and his collaborators in published papers 1 dealing with wheat 
rosette, was first observed by the writer near Granite City, 111., in 
1919 while studying the rosette disease. At that time little atten- 
tion was given to the foliage mottling which it manifests, because it 
occurred on varieties which did not develop the rosette condition. 
The following year, observations indicated that this foliage mottling 
bore some relation to the soil, and for this reason the disease was not 
seriously considered to be a true mosaic. Subsequent investigations, 
however, indicate that both this mottling and the rosette condition 
are manifestations of a transmissible mosaic disease, the virus of 
which is capable of existing for extended periods in certain soils. 
DISTRIBUTION AND IMPORTANCE 
Wheat mosaic has been found in Madison, Mason, Logan, and 
Cass Counties in Illinois and in La Porte and Porter Counties in 
Indiana. Rosette occurred in Sangamon County, 111., and Tippe- 
canoe County, Ind., in 1919, but since that time it has not been 
1 H. H. McKinney. Investigations of the rosette disease of wheat and its control. In 
Jour. Agr. Research, vol. 23, pp. 771-800, illus. 1923. 
S. H. Eckerson, and R. W. Webb. The intracellular bodies associated with the 
rosette disease and a mosaiclike leaf mottling of wheat. In Jour. Agr. Research, vol. 26, 
pp. 605-608, illus. 1923. 
R. W. Webb, and G. H. Dungan. Wheat rosette and its control. 111. Agr. 
Exp. Sta. Bui. 264, pp. 273-296, illus. 1925. 
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