fer the know seasonal histories and methods of infection of the fungi concerned are 
such as to indicate that at least as zreat a number of open as covered ears should 
become infected, The data at hand obviously indicate that well covered ears present 
more favorable conditions for infection by these fungi, just as open ears do for 
Fusarium and Penicillium; but it is not possible to say what these conditions are. 
It is clear, however, that in this group of rots the mechanical protection afforded 
by perfect husk coverage is no deterent to infection. 
SUMMARY 
In order to determine what relationship might exist between the field prev- 
alence of corn ear rot and the failure of husks to enclose the ear completely, data 
x a period of 5 
bearing on the question have been taken in Illinois corn fields during 
years, 1931-1955. A total of 57,395 ears huve been examined in 297 fields represent- 
ing all parts of the state. Analysis of the data so obtained has given the following 
information. 
Imperfect coverage of ears by husks is more common than perfect coverage. 
The proportion of open ears varied from year to year, ranging from 53 to 70 percent, 
but averaged 61 percent for the entire period, (See pp. 2 = 4 and Tables 1 and 2.) 
Ear rot is surprisingly prevalent in Illinois corn fields. Data taken dur- 
ing 4 years, 1952-1935, show a prevalence varying in different years from 28 to 90 
percent, and an average of 55 percent annually. (See pp. 4 - 5 and Table ee 
In corn ears not completely covered by husks the prevalence of rot ranged 
during 3 years, 1933-1935, from 40 to 92 percent and averaged 09 percent, In cars 
completely covered the prevalence of rot ranged from 24 to 88 percent and averaged 
49 percent. Among the rot infected cars entering into the above data those with open 
husks constituted from 57 to 67 percent in different years and for the entire period 
[18] 
