24 
jointworm, wheat placed in the barn before thrashing has been 
found much more likely to produce epidemics of this disorder, 
although the difference between wheat thrashed in the field and in 
the barn is not so striking as where the trouble results from abundance 
of the grain moth. 
A careful study of a large number of wheat fields in central Ohio 
by the Bureau of Entomology has shown that the infestation from 
the jointworm during the season of 1909 varied from 1 to 95 per cent. 
Here, too, the mite was found generally in the cells in the straw 
occupied by the jointworm larve. It has been found that in central 
Ohio September sown wheat is much more seriously affected by the 
jointworm than that sown in October, and also that the infestation is 
worse in both cases on poor soil than on that of an average degree of 
fertility, and still less on good soil. The infestation is invariably 
worse in fields on which wheat had been grown the previous year, and 
in fields lying adjacent thereto. Fail-plowed fields showed the least 
infestation of all. It appears, therefore, that moderately late-sown 
wheat on good soil and on land not devoted to wheat the previous 
year nor lying adjacent to such fields, escapes with the least injury, 
and that less difficulty with the dermatitis is experienced where 
wheat has been thrashed from the field and as soon as possible after 
the grain was harvested. As the jointworm winters over in the stub- 
ble, where this can be burned during fall, winter, or spring, the 
destruction of both the pest and the mite in the field will be com- 
plete. Where this can not be done, much good may be accomplished 
by raking over last year’s stubble fields in the spring and burning 
the stubble thus collected. So important are these measures that 
practicing physicians might almost include them with their pre- 
scriptions for this painful skin disorder. 
SUGGESTION TO CORRESPONDENTS. 
In order that this mite may be further studied with reference to its 
direct relation to man, all requests for information and correspond- 
ence relating to dermatological matters should be addressed to 
Dr. Joseph Goldberger, passed assistant surgeon, United States 
Public Health and Marine-Hospital Service, Hygienic Laboratory, 
Washington, D. C. All correspondence relating to entomological 
and agricultural matters connected with epidemics of this skin erup- 
tion should be addressed to the Bureau of Entomology, Department 
of Agriculture, Washington, D. C. 
Approved. 
JAMES WILSON, 
Secretary of Agriculture. 
Wasuineton, D. C., January 11, 1910. 
[Cir. 118] 
O 
