A MOSAIC DISEASE OF WINTER WHEAT AND WINTER EYE \) 
indicate that the causal agent does not persist in sandy soils as long 
as it does in silt soil. 
During the summer of 1920 two experiments reported previously 4 
were conducted on infested soil at Granite City, 111. In experi- 
ment No. 1 infested soil was placed in six galvanized-iron ash pails 
(5 gallons capacity). The soil in three of these pails was thoroughly 
disinfected with an 0.8 per cent solution of formaldehyde five weeks 
previous to sowing the seed. At the same time the remaining pails 
were thoroughly soaked with water. Harvest Queen wheat was sown 
in all of the pails in the autumn, and all pails were left in close 
proximity to each other throughout the fall, winter, and spring. In 
the spring 92 per cent of the plants in the pails containing the undis- 
infectecl infested soil developed rosette. Mosaic also occurred in 
these pails, but at that time the mosaic phase was not given great 
consideration, and complete counts were not made. All plants in 
the soil which had been disinfected were free from rosette and 
mosaic. Harvest Queen wheat growing simultaneously in the field 
in which this experiment was located developed 95 to 98 per cent 
of rosette. Mosaic also was prevalent, and various aerial forms of 
insects were abundant during the growing period. 
Experiment No. 2 was conducted in two infested plats (A and B), 
which were 4 feet wide and 6 feet long and surrounded by a board 
frame. These plats were only a few inches apart. The soil in both 
plats was thoroughly disinfected with formaldehyde to a depth of 
10 inches. Plat A was reinfested in the fall, when the seed was sown 
by scattering three-fourths of an inch of infested soil over the sur- 
face and in the seed trenches. Plat B was not reinfested. Harvest 
Queen wheat was sown in both plats. In the spring, mosaic and 
the rosette condition developed in 75 per cent of the plants in plat A. 
Wheat growing in plat B was healthy with the exception of a feAV 
diseased plants which developed at the edges of the plat. These 
plants undoubtedly became infected through the roots growing under 
the frame into the outside infested soil or through splashing or seep- 
age of infested material into the edges of the plat. 
During the summer of 1922 5 a small plat (24 by 30 inches) of 
infested soil located in a large uniformly infested area at Granite 
City, 111., was disinfected with formaldehyde. In the fall, Harvest 
Queen wheat was sown in the disinfected plat and also in much 
of the infested area outside of the plat. In the spring, mosaic 
and the rosette condition developed in 90 to 98 per cent of the 
plants growing outside of the disinfected plat, but all plants in 
the plat were free from mosaic and rosette, and they remained 
so throughout the growing season in spite of the fact that aphid s 
and chinch bugs were abundant. 
During 1922 infested soils from Granite City, 111., and from 
Porter County, Ind., 6 were transported to Madison, Wis., and 
placed out of doors in plats 3 by 4 feet in size. 
The first plat contained infested Illinois soil, the second plat 
contained infested soil from Indiana, the third contained infested 
Illinois soil which was steam sterilized before sowing the seed, and 
* H. H. McKinney. Op. cit. 
5 H. H. McKinney, S. H. Eckerson, and R. W. Webb. Op. cit. 
8 Tbe Indiana soil was from an experiment field maintained on a farm near Wanatah, 
Ind., by the Purdue University Agricultural Experiment Station. 
