April, ’24] 
mccolloch: corn-ear worm 
323 
cussed in a previous paper 3 in which it was shown that the number of 
eggs deposited on a variety was correlated with the time and period of 
silking and this in turn influenced the infestation. From the standpoint 
of the number of eggs deposited, it was found that Boone County White 
should be planted between April 15 and May 1; Commeicial White 
about May 1; and Kansas Sunflower and Hildreth between May 1 and 
May 15. 
The determination of the percent of grain injured supports the results 
already presented in that the May 1 plots had from 2 to 3 percent of the 
grain destroyed, while from 4 to 6 percent was injured in the April 15 
plot, and from 8 to 12 percent in the plantings of May 15 to June 12. 
Incidentally, it might be mentioned that the May 1 corn was compara¬ 
tively free of the various molds and fungi which usually accompany 
earworm injury. 
The number of overwintering pupae in a square rod of soil in each 
planting was determined during several years of the experiment. The 
results show that the number of pupae increased with the delay in 
planting. The first three plantings averaged from two to four living 
pupae per square rod, while the later plots had from eight to twelve. 
Summary 
An experiment to determine the best time to plant corn to obtain 
maximum yields and minimum earworm injury was conducted at Man¬ 
hattan, Kansas, for a period of ten years. Four standard varieties of 
corn were used and data were taken on all phases which are associated 
with earworm activities.' An analysis of all the data obtained in this 
study shows that May 1 is the optimum date to plant corn, although the 
results secured in the various phases of the investigation indicate that 
this date actually lies somewhere between April 15 and May 1. Ex¬ 
periments are now under way to determine the exact date when each 
variety of corn should be planted in Kansas to obtain the best yields 
and the lowest amount of earworm injury. 
President A. G. Ruggles: The next paper is by Leonard Haseman 
and S. W. Bromley. 
AMcColloch. J. W. A Study of the Oviposition of the Corn Earworm with Re¬ 
lation to Certain Phases of the Life Economy and Measures of Control. Journ. 
Econ. Ent., 13:242-255. 1920. 
