1 
= 
Ear rot varied in prevalence from year to year, within wide limits, being 
least abundant in 1935, when 28.1 percent of the ears examined were infected, and 
| most abundant in 1934, when 90.5 percent were infected. While various factors may 
have been concerned in these annual variations, as for example in 1934 when ear rot 
was undoubtedly greatly favored by prior damage done by corn ear worms, the signifi- 
eance of the ear rot problem in corn production is emphasized by the fact that of 
over 45,800 ears examined over a period of 4 years an average of almost 55 percent 
| were visibly infected with one or another kind of rote. 
7 
RELATION OF EAR ROT PREVALENCE TO HUSK COVERAGE 
Data on the relation of ear rot, without reference to particular causes, 
| and husk coverage have been taken over a period of 3 years, 1935-1955, and are sum- 
“Marized in Tables 4 and 5. Among those ears not completely covered by husks ear rot 
prevailed, as shown in Table 4, to a high degree in 1933 and to an especially high 
degree in 1934, when the percentage of rot-infected ears exceeded the uninfected ears 
by nearly 85 percents; but in 1955 the rotted ears, while still constituting nearly a 
Table 4.-= Prevalence of ear rot in corn ears not completely 
covered by husks, 1935-1935. 
Open ears | Number of ears 
Year ear Re | Rotted j Not rotted 
““"Poreent of ears 
Rotted |Not rotted 
1933 | 5,300 2,801 2,499 52.9 47.1 
1934 7,693 7,101 592 92.3 oT 
1935 8,424 | 2,686 | 5,738 31.9 68.1 
ee foe ee a). te TAD 
Average ee { _59.0 + 41.0 
third of the entire number, were less abundant than sound ears. In spite of these 
fluctuations, the average percentages for the 4 recorded years indicate a strong ten- 
dency for open ears to become infected more frequently than covered cars. 
Among those cars completely covered by husks, car rot prevailed to a high 
degree also, as indicated in Table 5, but the percentage of rotted ears was less than 
[5] 
