244 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
corn plants that were in silk, it seemed advisable to follow the silking 
of the different varieties in each plot to determine the relation existing 
between silking and oviposition. Accordingly, in 1913, a detail study 
of silking was undertaken. The number of ears bearing fresh or attract¬ 
ive silks were counted each day on the middle row of each variety in 
each plot, a silk being considered attractive from the time it appeared 
until it became dry. 
Climatic Data 
Climatological conditions, especially rainfall, have a direct bearing 
on the growth of the corn plant and also to some extent on the corn 
earworm. In order to properly interpret the data presented in this 
paper, the essential records of rainfall are shown in Table I. It usu¬ 
ally follows in the area under consideration that the various climatic 
conditions correspond to the rainfall. Periods of low rainfall during 
the growing season are generally associated with high temperatures and 
hot winds. Conversely an abundance of moisture usually means mod¬ 
erate temperatures and absence of hot winds. 
Table 
I—Summary 
of the Rainfall (in 
Months of 
Inches) at 
1913 to 1918 
Manhattan, 
Inclusive 
Kansas, 
FOR THE 
Growing 
Total for 
the three 
summer 
Year 
April 
May 
June 
July 
August September 
Total 
months. 
1913 
2.96 
7.18 
1.55 
0.17 
0.65 
5.69 
18.20 
2.37 
1914 
1.19 
2.33 
4.58 
2.40 
3.56 
5.76 
19.82 
10.54 
1915 
2.04 
9.45 
6.69 
12.01 
3.07 
3.92 
37.18 
21.77 
1916 
2.17 
6.40 
7.43 
1.92 
0.76 
8.12 
26.80 
10.11 
1917 
4.59 
5.04 
4.80 
0.68 
6.92 
1.63 
23.66 
12.40 
1918 
3.74 
4.89 
1.33 
2.26 
3.71 
2.31 
18.24 
7.30 
The years 1913, 1916, and 1918, were exceptionally poor corn years, 
due to the extreme drouth of midsummer and the prevalence of hot 
winds. These conditions had a direct influence on the number of silks 
present on the plants and consequently on the location of the eggs. 
Conditions were somewhat better in 1914 and 1917 with the result that 
the growth and development of the plants was more nearly normal. 
The best year of the six that these investigations have been under way 
was 1915, when the midsummer rainfall was excessive and the tempera¬ 
ture was moderate. 
General Observation on the Oviposition of the Corn Earworm 
in the Field 
Oviposition normally occurs at night, the adults being most active 
at this time. During the clear, hot days of midsummer, the moths 
usually begin flying and feeding about 5:30 p. m., and egg laying begins 
shortly after, continuing often until dawn. On cloudy days, or during 
the cool days of fall, oviposition may occur in the daytime. Until 
the corn crop is fully matured, eggs are rarely found on plants other 
