EIGHTEENTH ANNUAL REPORT OF STATE ENTOMOLOGIST 7 



inflicted a loss of $110,175 in this one comparatively small territory. 

 Although these losses took place on irrigable land, no water was 

 available until after the first of June. Were it not that irrigation 

 made it possible in some cases to reseed and grow a late crop on 

 part of the originally destroyed area, the loss would have been 55 

 per cent instead of 48 per cent of the acreage in that district. 



Farmers generally throughout Montana should realize that the 

 pale western cutworm is a pest of the first magnitude, ranking with 

 the alfalfa weevil and others of great power of destruction. 



This insect came into prominence for the first time in 1911 in 

 the southern part of the province of Alberta, Canada, where several 

 hundred acres of grain were destroyed and where in the following 

 year the estimated loss was between 30,000 and 35,000 acres. The 

 first record of its occurrence in Montana was in the northern part 

 of the state in 1915. Since that time it has been spreading south- 

 ward and in 1920 was found to occur quite generally over that part 

 of Montana east of the continental divide, with the exception of 

 some few districts in the southern part of the state. 



Every effort is being made to find a remedy for this insect and 

 the director of the Experiment Station has been as liberal as possible 

 in the allowance of research funds to this department for studying 

 this insect. We are glad to report that some progress has been 

 made and that a publication dealing with what is known about this 

 insect and methods for its control has just been issued and is now 

 available for distribution. 



FBUIT-TEEE LEAP-ROLLER 



The fruit-tree leaf-roller or Colorado leaf-roller, as it is some- 

 times culled, (Archips argyrospila) is doing serious and rather 

 extensive damage to apple trees in the Bitter Root Valley. Our 

 attention was first called to it during the spring of 1920 when reports 

 of its presence and the damage it was doing were brought to our 

 notice from Ravalli County. 



The eggs of this insect are laid by the parent moth on the bark 

 of the apple tree during July and hatch in the early spring just as 

 the leaf buds are unfolding. The very minute worms go to the 

 buds and soon secrete themselves by burrowing among the tender 

 leaves. As the leaves expand the worms web them together 

 and remain hidden. It is characteristic of this insect to appear in 



