214 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



POISONED MOLASSES FOR THE DESTRUCTION OF 

 NOCTUID MOTHS 



By E. H. Strickland, Entomological Branch, Ottawa, Can. 



The annual loss on the western prairies from the destruction of 

 grain crops by the Pale Western Cutworm {Porosagrotis orthogonia 

 Morr.) has amounted in recent years to several millions of dollars. Num- 

 erous experiments, conducted in the infested provinces and states, 

 have failed to produce an effective method of controlling this pest 

 in its larval stage. For this reason the problem of destroying the 

 adults before they have reproduced has received considerable attention. 



Three methods have presented themselves to us as a possible means 

 of gaining this end, namely, light-traps, molasses troughs and poisoned 

 molasses. In experimenting with these we have aimed at producing 

 a method that will have the following qualifications; all materials 

 used are readily prociirable in any farming community, very frequent 

 attention to traps is unnecessary, and it is inexpensive to operate. 

 The employment of poisoned molasses approaches more closely to the 

 fulfilment of these conditions than does either of the other methods. 



Light-Traps 



In 1913, we placed a few light-traps in fields around Lethbridge, 

 where an outbreak of P. orthogonia had been somewhat severe. The 

 nightly catch never exceeded fifty-eight moths of this species and of 

 the total captures 97.5% were males. For this reason we considered 

 the method to be economically ineffective. In 1920, Circular 94 of 

 the Montana Experiment vStation recorded a night's capture of as many 

 as 1,500 moths of this species in individual light-traps which were of 

 a superior type to that which we had used in 1913. This year Mr. 

 H. L. Seamans, who has recently come from the Montana Station to 

 take charge of the Dominion Entomological Laboratory at Lethbridge, 

 constructed a number of traps similar to those in which these large 

 captures were made. Two of these were set out in a badly infested 

 field at Lethbridge and about six were operated by our assistant, Mr. 

 W. Carter, with the help of some farmers in the very heavily infested 

 district around Retlaw, which is about sixty miles to the north-east 

 of Lethbridge. These traps were set out from the middle of July till 

 September 8th, when snow and frost put an end to the flight of P. 

 orthogonia. During periods of moonlight, high wind and other un- 

 favourable weather these traps were not operated. The results were 



