1924 



ENTOMOLOGICAL SOCIETY 



81 



In 1922, after the first late planting suggestion, the planting dates were 

 materially changed. The following tabulation summarizes the general 

 situation : 



Tabulation Showing the Proportion of Each Type of Field Corn Grown and the 

 Seasonable Distribution of the Planting Dates in the Control Area 

 For the Years 1921-1923 



Year 



Type 



of 

 Corn 



Per Cent. 



of 



Crop by 



Type 



Per Cent. 



of Crop 



planted by 



May 24 



Per Cent. 



of Crop 



planted by 



June 1 



Per Cent. 



of Crop 



planted by 



June 6 



Per Cent. 



of Crop 



planted after 



June 6 



1921 



Flint 

 Dent 

 Flint 

 Dent 



Flint 

 Dent 



55.5 

 44.5 

 24.5 

 75.5 



38.5 

 61.8 



45 



10 



10 









 



78 

 85 

 26 

 28 



20 

 46 



85 

 90 

 60 

 60 



55 

 53 



15 



1922 



10 

 40 



1923 



40 



45 





47 



From the above table the abrupt drop in the percentage of flint corn grown 

 is clear, particularly in 1922. This change in variety of corn used was accom- 

 panied by a retardation in the date of planting, the most important change 

 being in the amount of corn planted before the 1st of June. As can be noted, 

 in 1923, though the proportion of flint corn increased, the average planting 

 dates for the whole crop were, if anything, even a little later than in 1922. 

 The increased planting of flint corn was due to the increased confidence of the 

 farmers which followed the excellent results of the control operations in 1922. 



In very large measure the freedom of the corn in 1922 from severe loss 

 could be ascribed to the late planting, while that of 1923 was due in largest 

 measure to the reduction in numbers of moths and the dilution of the attack 

 associated with the late season. 



As has been noted above, the control was not as effective in 1923 as in 

 1922 in spite of the still further retardation of the planting dates due in this 

 case, both to design and weather conditions. This increase in infestation was 

 due chiefly to the very late spring. The cool weather held the development of 

 the insect back even more than it retarded the development of the corn, with 

 the general result that much of the corn was in condition to serve as good egg- 

 laying quarters from the time that the moths began to fly. Egg-laying in 1923 

 did not begin till July 4th, which was at least 13 days later than in 1921 or 1922, 

 and continued in appreciable quantities till August 2nd; even after that date 

 scattered eggs were being laid. This resulted in distributing the attack and 

 reduced the extreme infestations. There were but two fields in the control 

 area which suffered measurable damage, and at the end of the season the control 

 area as a whole contrasted most favourably with the surrounding country. 



Sharp contrasts in the demonstration of the value of control efforts were 

 difficult to obtain owing to the fact that a great deal of publicity for control 

 practice has been carried on. Growers throughout the whole of the originally 

 severely infested area have, to a greater extent than they realize, put the sug- 

 gestion into practice. This is particularly true of the practice of late planting. 

 The general quality of the ploughing has also improved greatly, and the habit 

 of cleaning out the barnyards and the burning of miscellaneous corn refuse is 

 increasingly prevalent. 



