Mar. io, 1923 
Rosette Disease of Wheat and Its Control 
773 
DISTRIBUTION 
So far as definitely known, the rosette disease of wheat occurs only in 
the States of Illinois and Indiana. Table I gives the counties in which 
the disease has been located and the number of fields and areas infested 
in each. 
TabIvE I .—Distribution and severity of the rosette disease in the United States in igig 
State. 
County. 
Number of 
fields 
infested. 
Acreage in 
infested 
fields. 
Extent of disease in infested 
fields. 
[Madison. 
25 
629 
Trace to 85 per cent. 
Illinois. 
Mason.. 
48 
h 310 - 5 
380 
Trace to 70 per cent. 
' Sangamon. 
Logan. 
2 
I 
Trace to 5 per cent. 
[Laporte. 
5 
IS© 
Trace. 
Indiana. 
Porter.... 
6 
120 
Trace to 63 per cent. 
Trace. 
Tippecanoe. 
1 
5 
ECONOMIC IMPORTANCE 
While the occurrence of this trouble is restricted to relatively small 
areas, its importance must not be overlooked. Under ideal conditions 
for the disease it has caused as high as 40 per cent actual loss of grain 
in a 50-acre field. It is not uncommon to find many spots or large areas 
in a field where practically all the wheat plants are killed. Sometimes, 
however, the diseased plants in such spots recover to a considerable 
extent and produce some grain. However, such plants usually are so 
delayed in ripening that they are green when the normal crop is har¬ 
vested. The grain from such green plants shrivels badly, and much of 
it is lost in thrashing. When much of a field is affected by the disease 
and there has been considerable recovery, the greatest quantity of grain 
is saved by delaying harvest until the diseased areas are ripe. It fre¬ 
quently is more economical to take a small loss, due to the shattering of 
overripe healthy plants, than to harvest the recovered plants while green. 
In some cases, where diseased areas in a field are more or less segregated, 
it is possible to harvest the healthy and diseased areas separately, thus 
reducing losses to the minimum. 
HOST PLANTS 
Investigations carried on thus far have not shown any other crop than 
wheat to be positively affected by the rosette disease. Results of at¬ 
tempts to infect various plants will be found in Table II. There is some 
suggestion that rye may be infected, but this is not certain. While 
further investigations are being conducted to throw additional light on 
the host range of the disease, it is considered unnecessary to include 
plants outside the grass family until more is known about the cause of 
the disease. 
