320 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
[The European Corn Borer papers were presented at this point in the 
program. They were published in the February issue, pp. 112-159, as 
directed by vote of the association. Editor.] 
President A. G. Ruggles : The next paper will be presented bv 
J. W. McColloch. 
THE TIME OF PLANTING CORN AS A FACTOR IN CORN-EAR 
WORM CONTROL 1 
By J. W. McColloch, Kansas State Agricultural College 
Abstract 
Experiments which have been under way at the Kansas Station for ten years show 
that there is a definite relation between the date of planting corn and injury by 
corn-ear worm, Heliothis obsoleta Fabr., As a rule, the date of minimum ear worm 
injury and maximum yields coincide. The problem has been studied from several 
angles and these are discussed briefly in this paper. 
In 1909 the Department of Entomology of the Kansas State Agri¬ 
cultural College began an investigation to determine the relation existing 
between the time of planting corn and the amount of corn earworm in¬ 
jury. Previous studies had shown that there was little hope of effecting 
a complete control of this insect, but that injury could be materially 
reduced by regulating the date of planting. The general plan of the 
experiment and the results of the first year were presented before this 
association in 1910 2 and it is the purpose of this paper to summarize the 
results obtained during the ten-year period 1909 to 1919. 
Plan of the Experiment 
Each year this investigation was based on a series of five plots of corn 
planted at intervals of 15 days, beginning the middle of April. Three 
standard varieties of corn; namely, Boone County White, Kansas 
Sunflower, and Hildreth were grown in each plot throughout the ex¬ 
periment, and Commercial White was added in 1913. Each variety was 
planted in a three-row series, the rows varied from 100 to 200 feet in 
length during the different years, but w^ere the same length each year, so 
the results are comparable. Plantings were made on April 15, May 1, 
May 15, June 1, and June 15. This experiment was conducted on the 
same area during the last eight years and the land was handled in the 
same manner as is usually followed by the average farmer. The rows 
Contribution No. 329, from the Entomological Laboratory, Kansas State Agri¬ 
cultural College. This paper embodies some of the results obtained in project No. 
9 of the Kansas Agricultural Experiment Station 
2 Headlee, T. J., Notes on the Corn Earworm. Journ. Econ. Ent., 3:149-157, 1910. 
