that fields were examined in 69 of the 102 counties in the State. 
DEFINITION OF TERMS 
Throughout this discussion "covered" and "well covered" are to be understood 
as signifying that ears so classed were covered completely by husks, including the 
tips, and that the husks remained tightly closed until near harvesting. For the first 
2 years, 1931 and 1932, these terms apply rigidly to ears observed to be completely 
and tightly covered by husks when the fields were examined. "Open," "not covered," 
and "not well covered" signify that ears so classed were not completely covered, but 
no distinctions have been made relative to the degree of partial coverage and none is 
implied by the various terms used. 
Since the data are concerned with visually discernible ear rots, "ears with 
visible infection" and "ears without visible infection" constitute the 2 classes into 
which corn ears were assorted upon examination, Ears were considered to be rot-free 
if, at the time of examination, no visible mold or fungus sporulation appeared on or 
between the kernels or on the cob, Heaeely, no account could be taken of the hidden 
infections which require the use of a germinator for determination. 
RELATIVE ABUNDANCE OF COVERED AND OPEN EARS 
Since most of the corn seed used in Illinois is produced by open pollina- 
tion and is genetically heterozygous, it might be expected that covered and open ears 
would be found to occur in approximately equal numbers. However, an increasing num- 
‘ber of farmers are practicing field seed selection, and, since this involves the 
choice of covered in preference to open ears, the expected ratio may not be secured. 
It is commonly believed, also, that weather and other conditions tend to influence 
ear length and size, thereby determining whether the cars will be covered or not by 
the supposedly uniform husks, 
[2] 
