Nov. 5, 1921 



Pale Western Cutworm 



311 



This was scattered in coarse droplets over flowers and vegetation 

 where moths were abundant. Many flies and bees were killed, but no 

 moths were observed feeding upon the bait, and dead moths were never 

 found in the vicinity of the sprayed vegetation. 



CUI^TURAI, METHODS AS A MEANS OF CONTROI, 



In our study of Porosagrotis orthogonia under field conditions we have 

 repeatedly noticed instances where crops in one field were completely 

 destroyed, while in an adjacent field the grain escaped unharmed. This 

 suggested that the manner in which the ground was worked before the 

 crop was put in might have been responsible for the great difference in 

 the amount of damage done in the two fields, and in 1920 a survey was 

 conducted with the object of determining the relation of cultural methods 

 to cutworm abundance. This survey was conducted in two ways : (1) By 

 an auto trip through the districts most heavily infested by means of which 

 hundreds of farmers were personally interviewed and the histories of 

 their fields obtained for the period 1919-20; (2) by questionnaires sent 

 to all farm bureau members in counties where Porosagrotis orthogonia was 

 known to be present. 



The percentage of cutworm losses under various cultural methods as 

 shown by a study of fields, the owners of which were personally inter- 

 viewed, is shown in Table VI. 



Table Vl. ^Percentage of Porosagrotis orthogonia injury in IQ20 under various methods 

 of cultivation in preparation for seeding 



Cultivation between previous crop and 1920 crop. 



Percentage 

 lost. 



Fall double disked 



Spring double disked 



Spring single disked 



Fall-plowed ; disked or harrowed be 'ore seed- 

 ing 



Spring-plowed" disked or harrowed before 

 seeding 



Spring-harrowed 



Summer-fallowed 



43- o 

 57- o 

 43- o 



21. o 



27. o 

 40. o 



8.5 



A study of the results shows a high percentage of cutworm injury in 

 all cases where the stubble was only disked or harrowed before seeding. 

 Fields which were plowed either in the fall or spring showed a somewhat 

 lower percentage, while summer-fallowed fields showed only the very 

 small loss of 8.5 per cent. 



While the average cutworm loss in summer-fallowed fields was low, 

 yet several individual fields suffered severe losses. It was therefore 

 decided to make a study of the histories of summer-fallowed fields during 

 the two seasons of 19 19 and 1920. Since the moths were known to 



