correlation between exposed ears and abundance of infection arrues strongly against 
the protective effect of complete husk coverage and emphasizes to an equal derree 
the important role, in this disease, of ear invasion throuvh the shank and silks. 
The classification of the Gibberella infected ears with respect to husk 
coverage is given in Table 15, In 1931 and 1932 the open infected ears exceeded in 
number the covered infected ears, but in each of the 3 later years the reverse was 
Table 15.-- Relation of Gibberella ear rot to husk coverage, 
1931-1935, 
me we ee ee ee 
ee oe ae 
ee re e+ 
“) Bxcess oF 
Number of rotted saab pence: of rotted ears 
open, in 
Year Open j Covered | Open | Covered _! percent 
i i { 
1931 ae 9 4) | (6940 31.0 38.0 
193¢@ 26 Lo 57,8 4202 | 15.6 
1936 10 ig 545 65.5 - 51,0 
1934 53 | 67 53.0 67.0 - 54.0 
1935 ee | 21.3 6.7). | in Bias 
Average eee tien ETS aie Beak a ili 
true, so that for all the years considered open ears were fewer by 13.7 percent an- 
nually than covéred ears in the infected lots. This general tendency seems to indi- 
cate that perfect coverage by husks is, in fact, no protection but may be conducive 
to a greater abundance of infection, Such a conclusion serves, perhaps, to emphasize 
the already recognized importance of infection by way of the silks. 
The numbers and proportions of open and covered ears among the Basisporium 
infected ears found each year are given in Table 16. The number of infected ears 
found in 1931, 1932, and 1933 was small, A definite preponderance of open infected 
ears occurred in 1931 and 1932, but in each of the succeeding years covered infected 
ears predominated to such an extent that for all 5 years they exceed by an average 
of 9.6 percent annually the proportion of infected open ears, In this, as in the 2 
[14] 
