894 ANNUAL REPORT OF THE Off. Doc. 



silken cocoon around itself within the grain. In this cocoon it trans- 

 forms from the caterpillar to the moth and when this change has been 

 completed the moth pushes out the circular piece cut by the cater- 

 pillar in the surface of the grain, and escapes. This usually occurs 

 in August, and the moths, therefore, find themselves either in the 

 stack, when threshing has not yet been completed, or wherever the 

 grain has been stored. They now proceed to lay the eggs for a 

 second brood which has a similar history. The work of this brood, 

 like that of the first, is generally overlooked until the moths ap- 

 pear, at which time the abundance of the little ''millers" around the 

 bins and granaries, and the holes in the grains become noticeable. 

 If the temperature of the place where the grain is stored be high 

 enough, the moths lay their eggs for a third brood and if conditions 

 permit will continue breeding through the winter. Usually, how- 

 ever, in Pennsylvania but two broods occur, and the insect passes the 

 winter in whatever stage it happens to be when cold weather over- 

 takes it. 



Parasites and Treatment. 



There are two foes to the Angoumois grain moth in Pennsylvania 

 — a mite, and a minute insect known as C'atolaccus. The latter has 

 been quite abundant in this Commonwealth and has prevented some 

 loss, but has failed to control the grain moth. Treatment should 

 therefore be resorted to. 



For the first brood of the grain moth nothing can be done as the 

 insect is working inside the grain while it is yet uncut in the fields. 

 After harvesting, however, the second brood can be cheaply and 

 easily handled. 



In order to successfully treat the grain at this time, it is desirable 

 to thresh it as soon as possible after harvesting. Then when the 

 grain has been placed in the bins it can be fumigated with carbon 

 bisulfide and all the insects destroyed. 



To properly use the carbon bisulfide, the following directions 

 should be followed: See that the bin is tight and that it can be closed 

 so as to be fairly tight at the top, though this is less important. 

 Place shallow dishes on the top of the grain and pour the carbon 

 bisulfide into these; then close the bin and leave it undisturbed for 

 twenty-four hours, after which the cover may be lifted and the bin 

 left to air for an hour. Now stir over the grain to find if all the in- 

 sects have been killed, and if any remain (which is not usually the 

 case) repeat the treatment. 



The quantity of carbon bisulfide to use depends on the size of the 

 bin, the usual amount being one pound (costing twenty-five or thirty 

 cents) to every thousand cubic feet contained in the bin. Thus one 

 pound would be suflScient for a bin ten feet wide, ten feet long and 



