236 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



black horn flies, which are especially bothersome on ac- 

 count of their great numbers. 



Flies breed in filth or decomposing matter of various 

 kinds, horse manure appearing to be the most favorable 

 material for house flies, wet and rotting straw or other vege- 

 tation for stable flies, and cow manure for horn flies. Clean- 

 ing up, treating, or screening their breeding places is an ef- 

 fective method of combating flies. This is especially true 

 if a large area is covered, such as a whole community. The 

 individual farmer can do much to lessen the number of flies 

 on his farm, as the major part of them, under usual farm 

 conditions, are produced there. Since flies will travel for 

 miles, however, the effectiveness of this method depends to 

 some extent on the distance from other favofable breeding 

 places. 



One of the most effective methods of decreasing the 

 trouble from house flies is to keep all food away from them. 

 See that there is no spilled milk for them to feed on; also 

 that all soiled mangers that attract flies are cleaned. If 

 there is nothing for a house fly to eat it will not stay around. 

 Fly traps will catch a great number if properly baited. They 

 will also attract flies into the barn, and for this reason it is 

 better to set the traps outside rather than inside the build- 

 ings. Poison made by using a solution of formalin and milk 

 in the proportion of 3 teaspoonfuls of commercial 40 per 

 cent formalin to 1 pint of sweetened milk gives good re- 

 sults. In using this poison, blotting paper may be placed 

 in the bottom of shallow pans and the paper barely covered 

 with liquid. As the liquid dries out it should be renewed. 



Since stable flies are not attracted by bait of any kind, 

 the method of combating them is to keep them away from 

 the stock by darkening the stable, blanketing the cattle, or 

 using some sort of fly repellent on the animals. No repellent 

 has yet been devised that will protect the animals for more 

 than a few hours. A repellent composed of the following 

 is probably as effective as any: Oil of tar, 10 parts; cotton- 

 seed oil, 10 parts; and paraffin oil, 80 parts. Although flies 

 worry cows considerably, the presence of limited numbers 

 does not materially effect milk production. 



