788 
Journal of Agricultural Research voi. xxm, No. 10 
careful counts, as there was no striking indication of the characteristic 
stunting or blue-green color which occur on plants affected by rosette 
disease. Comparisons between Tables III and VI will show that while 
there is an increase in tiller development from the Helminthosporium 
inoculations, this increase is somewhat less than that found in plants 
showing rosette disease under field conditions. 
While these are only preliminary data they indicate that Helmin¬ 
thosporium is capable of stimulating tiller development. 16 
TabIvE VI .—Influence of Helminthosporium infection upon tiller development in Mar¬ 
quis and Harvest Queen ( white-chaffed Red Cross) wheat 
Variety. 
Susceptibility to 
rosette disease. 
Number of 
plants. 
Reduc¬ 
tion in 
stand 
on inoc¬ 
ulated 
series. 
Average number 
of tillers per 
plant. 
Inocu¬ 
lated 
series. 
Uninoc¬ 
ulated 
series. 
Inocu¬ 
lated 
series. 
Uninoc¬ 
ulated 
series. 
Marquis. 
Harvest Queen (white-chaffed 
Red Cross). 
Questionable. 
Positive. 
240 
270 
263 
297 
Per ct. 
8.7 
9.0 
2. 66 
4*05 
2. 65 
2. 74 
The correlations and other indirect evidences presented show that, 
under certain conditions at least, Helminthosporium is very closely 
associated with the rosette disease, and, as pointed out by the writer 
(20), there is a suggestion that the disease possibly may be an unusual 
manifestation of the Helminthosporium disease of wheat which has 
been known for some time to be present in several States (/), (10), (32), 
in the spring- and winter-wheat belts. Studies now under way will 
throw additional light upon the relation of this and other organisms 
to the development of the disease in question. 
TOXINS AND VIRUSES 
This group of factors has been considered among the possibilities of 
cause, and experiments now under way should throw some light upon it. 
intraceixuuar bodies 
While it is possible that the intracellular bodies mentioned earlier in 
this paper may be some unusual type of organism which bears some rela¬ 
tion to the cause of the rosette disease, it is also possible that they are 
reactionary bodies produced in the cells as a result of the disease. 
Although these bodies have been found associated with the rosette 
disease, they have also been found associated with a mosaic-like leaf 
mottling in plants not showing the dwarfing characteristic of plants 
affected with the rosette disease. Thus far these intracellular bodies 
have not been found in wheat plants showing neither the rosette dwarfing 
nor mosaic-like leaf mottling. Further studies on both diseased and 
healthy plants are necessary before the nature of the bodies and their 
relation to the disorders can be definitely determined. 
16 Various workers, including Grantham (5) and Rimpau (28), have shown that tillering is stimulated 
by wide spacing between wheat plants. While the slight seedling killing in the inoculated plots resulted 
in a slight increased spacing, such spacing was practically the same in both varieties. Furthermore, no 
results have yet been found which indicate that such a small, irregularly distributed increase in spacing 
will increase tillering to the extent manifested in Harvest Queen (white-chaffed Red Cross) wheat. 
