THE IMPOETAXT PUXGICIDES 



15 



Water. — The use of water heated to 132^° F. has 

 recently come into practice to destroy the spores of grain 

 smuts in or on the seed. The water should not get 

 above 135°^ nor below 130°^ while the seed is immersed. 

 Full directions for this treatment will be found in the 

 discussion of wheat and oats smuts. 



Bordeaux Mixture. — This fungicide originated 

 in France^ and has become one of the leading combina- 

 tions of copper salts. Since its introduction into Amer- 

 ica there has been a constant tendency to dilute the mix- 

 ture more and more. The results from the diluted 

 mixtures have been apparently as good as from those of 

 full strength, and, of course, the cost has been propor- 

 tionately lessened. The different formulas are indicated 

 below : 



Original Formula. — Dissolve six pounds of copper 

 sulphate in one gallon of hot water in an earthen or 

 wooden vessel. In another vessel slake three pounds of 

 fresh lime in one gallon of water. Strain the latter and 

 add to twenty gallons of water. Xow pour in the dis- 

 solved copper sulphate and mix thoroughly. Keep the 

 mixture stirred while using. 



Half-strength Formula. — In 1889, while at the 

 Ohio Experiment Station, I experimented with jDotato 

 blight by diluting this mixture a little more than half, 

 using six pounds of copper sulphate and four pounds of 

 lime to a barrel (fifty gallons) of water, instead of 

 twenty-two gallons. This was applied to a number of 

 plants besides potatoes, and, apparently gave as good 

 results as undiluted mixtures. The same formula was 

 also successfully used in 1890, and has since been quite 

 generally adopted, being now recommended by the 

 United States Department of Agriculture. Mr. Gallo- 

 way suggests the following method of procedure : 



^^In a barrel that will hold forty-five gallons dissolve 

 six pounds of copper sulphate, using eight or ten gallons 



