THE INTRACELLULAR BODIES ASSOCIATED WITH THE 
ROSETTE DISEASE AND A MOSAICLIKE LEAF MOT¬ 
TLING OF WHEAT 1 
By Harold H. McKinney, Pathologist, Sophia H. Eckerson, Microchemist, 
and Robert W. Webb, Assistant Pathologist , Office of Cereal Investigations, Bureau 
of Plant Industry, United States Department of Agriculture 2 
INTRODUCTION 
It is the purpose of this paper to describe briefly the intracellular 
bodies found in wheats affected by the rosette disease and the mosaic¬ 
like leaf mottling. The literature bearing on the problem will be 
reviewed in another publication. 
In a recent abstract by the writers 3 and in a paper by McKinney 4 
attention was called to unusual intracellular bodies which appeared to 
be associated with the rosette disease of wheat (PL i). It was pointed 
out in these publications that the intracellular bodies are also associated 
with a mosaiclike leaf mottling occurring on wheat plants which may or 
may not show the rosette symptoms (PL 2), and it was also pointed out 
that it is not definitely known whether wheat rosette and the leaf-mottled 
condition are different responses to the same causal agent or whether they 
are due to separate causes. Observations made on field experimental plots 
conducted at Granite City, Ill., during 1923 show certain relationships 
between the two manifestations which suggest that they may be due 
to one causal agent. This correlation seems even more striking than 
the correlation 5 which is sometimes noted between the rosette disease 
and the occurrence of Helminthosporium sativum . 
Although the leaf mottling in wheat is typical for the mosaic diseases 
of the Monocotyledons, there are indications that it behaves somewhat 
differently from these latter diseases in that the causal agent for the 
leaf mottling of wheat appears to be carried over from year to year in 
the soil. In field experiments conducted in 1923 at Granite City, Ill., 
and Madison, Wis., with heavily infested soil, rosette and leaf mottling 
occurred on from 95 to 98 per cent of the wheat plants of a susceptible 
variety (Harvest Queen). When such infested soil was disinfected with 
formaldehyde or steam and subjected to the same conditions as the 
infested soil, rosette and leaf mottling apparently were completely absent 
throughout the entire growing season. This control was effected at 
Granite City, Ill., even though the apparently healthy plants were sur¬ 
rounded by thousands of wheat plants showing an abundance of leaf 
mottling. In addition, flying insects, especially aphids and chinch bugs, 
were abundant during certain periods. 
1 Accepted for publication Nov. 1, 1923. 
* These investigations have been carried on in cooperation with the Wisconsin and Illinois Agricultural 
Experiment Stations. 
•McKinney, H. H., Eckerson, Sophia H., and Webb, R. W. intracellular bodies associated 
with THE rosette disease op wheat. (Abstract.) In Phytopathology, v. 13, p. 41. 1923. 
4 McKinney, Harold H. investigations op the rosette disease op wheat and its control. In 
Jour. A^gr. Research, v. 23, p. 771-800, 2 fig., 8 pi. 1923. Literature cited, p. 799-800. 
5 - the so-called take-all disease op wheat in Illinois and Indiana. (Abstract.) In Phy¬ 
topathology, v. it, p. 37. 1921. 
(60s) 
Journal of Agricultural Research, 
Washington, D. C. 
ahv 
Vol. XXVI, No. 12 
Dec. 22, 1923 
Key No. G-346 
