INJURIOUS INSECTS 



307 



in stored grains. For root insects it is poured into 

 holes, which are immediately closed up, causing the 

 fumes to permeate the soil in all directions. For in- 

 sects in grain bins, pans of this liquid are placed <m 

 the tup of the grain or stored material. The vapor 

 descends through the stored material. About a tea- 

 spoonful is required for each cubic foot of space. 

 Lighted lamps, fire, lighted pipes or cigars must be 

 kept from the building while this method of fumiga- 

 tion is in progress. 



BORDEAUX MIXTURE. - This is primarily a fungi- 

 cide, but has likewise insecticide qualities in certain 

 cases. It is frequently used to good effect at the same 

 time with arsenical sprays for apple scab and other 

 fungous diseases. Paris green is much more prefer- 

 able in composition with the Bordeaux mixture. The 

 formula fur the Bordeaux mixture is as follows: 



Sulphate of copper 6 Ibs. 



Quicklime 4- Ibs. 



Water 40 gals. 



Dissolve the copper sulphate in 4- gallons of water; 1 

 slake the lime in another vessel; add the milk of lime 

 slowly to the copper sulphate, stirring constantly. 

 Strain through a sieve or coarse-grained guimysack, 

 and add the remainder of the water. The mixture is 

 ready for use. A simple test to make sure that enough 

 lime is present in the mixture to properly protect, the 

 plant, is to place some bright metal substance, such as 

 a knife-blade, in the Bordeaux mixture. If when the 

 blade is withdrawn there is an appearance of copper 



1 The best way to dissolve the sulphate of copper is to suspend it la the water by 

 means of a bag of coffee-sacking. Use the pulverized sulphate. 



