rots can be shown for any year and the fluctuations of each in abundance from year to 
year can be ascertained readily. An average, for the 5 years covered by the data, of 
these yearly indexes may be considered to show with a fair degree of accuracy the 
average annual vrevalence of each rot, 
On this basis the several rots assume the order given in Table 8, Fusarium 
rot is shown to be the most prevalent, every year as well as in the average year, for 
which its index is 41 percent, while Penicillium rot stands second, with a moderate 
prevalence each year and an average annual prevalence of 6 percent. Between Fusarium 
and the remaining diseases a very large gap in both vear-bveyear and average preval- 
ence is shown, the average index for Penicillium rot, most abundant of the 7, being 
less by 35 percent than that of Fusarium rot. The average annual indexes indicate, 
in fact, that over a period of years the last 7 of the 8 ear rots have an aggregate 
prevalence approximately one-third that of Fusarium rot. 
In the annual variations there is no general agreement among the 8 rots as 
to trend for the entire period. There are, however, two rots which follow the same 
trend throughout the entire period. Rhizopus rot and Aspergillus rot both increase 
in prevalence in 1932 over 1931, in 1933 over 1932, and in 1934 over 1955, and both 
decline very markedly in 1935 from the high points of 1934, Smut and Basisporium rot 
also agree in trend, except for 1933, in which year the former declined from and the 
latter rose above the prevalence of the year before. With the other rots, similar 
trends may exist for short periods, but the. parallelism does not hold for the entire 
number of years. 
RELATION OF SPECIFIC EAR ROTS TO HUSK COVERAGE 
When the data presented in the preceding section were taken, the corn ears 
affected with each rot were classified as to coverage by husks, according to the 
[9] 
