Nov. 5. 1921 Pale Western Cutworm 307 



EXPERIMENTS IN CONTROL 

 ORDINARY CUTWORM CONTROI, METHODS NOT EFI^ECTIVE 



Early in our study of Porosagrotis orthogonia it became apparent that 

 the ordinary method of scattering poisoned bran mash over an infested 

 field was not effective in controlling this species. On May 2, 19 19, pois- 

 oned bran mash was scattered over a heavily infested field in southern 

 Montana at the rate of 20 pounds to the acre and was followed by three 

 other applications on successive days. The field was exammed each 

 day by the owner, who reported that he could not find a single dead worm. 

 On May 7 the treated area was carefully examined by one of the writers 

 but no dead worms could be found, nor could any decrease in the number 

 of live worms be noted. On May 7, 19 19, poisoned bran mash was scat- 

 tered over 2 acres of heavily infested wheat in northern Montana. During 

 the next 10 days no results whatever were secured from this treatment. 

 County agents and numerous farmers have reported that attempts to 

 poison this species by the ordinary method of scattering poisoned bran 

 mash over the surface have always resulted in failure. 



At Willow Creek in 1920 pale western cutworms were noticed crawling 

 over the surface of the groimd in the evening after a rain, and an attempt 

 was made to kill them by scattering poisoned bran mash during the 

 night. The bait was scattered soon after dark over an area which in- 

 cluded bare ground, scattering wheat, and a good stand of wheat, all 

 heavily infested. Observations were made during the night by the aid 

 of automobile headlights, and many of the worms were seen feeding upon 

 the bait. Two days later a search was made for dead cutworms. In 

 the area where there was no vegetation it was estimated that 60 per 

 cent of the worms were killed; where there was a scattering of wheat 

 the percentage of dead worms was 50; and where there was a good stand 

 of wheat 43 per cent were killed. It is possible that several night appli- 

 cations of poisoned bran mash during rainy weather might bring about a 

 satisfactory control, but as yet we have not had the opportunity to 

 try it. 



POISONED BRAN MASH HARROWED INTO THE SOU. 



Strickland reports {17) that poisoned bran mash harrowed into the 

 soil gave gratifying results. This method was tried out at Wilsall in 

 May, 19 19. Poisoned bran mash was scattered over 3^ acre of heavily 

 infested wheat at the rate of 25 pounds to the acre. On several square 

 rods where the worms were thickest the mash was worked well into the 

 soil with a hand rake, and the remainder of the treated area was thor- 

 oughly worked with a spike-toothed harrow. The plot was carefully 

 examined three days after the poisoned bran mash was applied, and it 

 was estimated that the treatment was not more than i per cent effective. 

 Very few dead cutworms could be found, and eventually all of the wheat 

 was destroyed. 



