April, ’20] McCOLLOCH: OVIPOSITION OF THE CORN EARWORM 
253 
emerged. An analysis of the data indicates that from the standpoint 
of the number of eggs deposited, Boone County White can be planted 
from April 15 to May 1, Commercial White about May 1, and Kansas 
Sunflower and Hildreth from May 1 to May 15. Summarizing the 
results for the four varieties, May 1, under favorable conditions, is 
apparently the optimum time to plant corn to escape injury from the 
corn earworm. 
Relation of Oviposition to Different Varieties of Corn 
The number and location of the eggs is worthy of consideration in a 
study of the resistance of different varieties of corn to earworm injury. 
Thus far little work has been done along the line of immunity, and in 
the investigations that have been conducted emphasis has been placed 
on the presence or absence of larval injury with relation to the mor¬ 
phological characters of the plant. Collins and Kempton, 1 in breeding 
sweet corn resistant to the corn earworm, considered four protective 
characters, namely: the distance the husk extends beyond the ear; 
the thickness of the husk covering; the texture of the husk, and the 
presence or absence of husk leaves. While a study of the plant char¬ 
acteristics is of great importance in such an investigation it would seem 
that a study of the oviposition would be important in correlating and 
interpreting the results. As has been pointed out; the moths show a 
preference for the silks, and, as will be shown, there is a direct relation 
between silking and the number of eggs deposited. The present 
studies also show that fewer eggs are deposited on the husks than on 
any other part of the plant. In the investigations under discus¬ 
sion, there has been considerable variation in the number of eggs 
deposited on the four varieties grown in the plots, a condition that 
has prevailed practically every year. A study of the data presented 
in Table II shows that in 43.7 per cent of the 32 plots grown in the 
six years, Boone County White has had the lowest number of eggs, 
Kansas Sunflower has had the fewest eggs in 28.3 per cent of the 
plots, Commercial White in 15.6 per cent, and Hildreth in 12.5 per 
cent. 
A comparison of the data summarized in Table III indicates that 
there is also a similar variation in the location of the eggs on the 
different varieties, although this difference is not so pronounced. 
During the time these investigations have been in progress, fewer 
eggs have been found on all parts of Boone County White, except 
the husk (Table IX), than on each of the other varieties. Likewise, 
1 Collins, G. H., and Kempton, J. H., Breeding Sweet Corn Resistant to the Corn 
Earworm. In Jour. Agric. Research, Vol. XI, No. 11, p. 549-572. 1917. 
