INSECTICIDES AND FUNGICIDES 



273 



FUNGICIDES 



When all has been said the number of fungicides approved by the 

 experience of practical and scientific men is very small. Many have been 

 recommended, but comparatively few have stood all the tests as to effective- 

 ness, convenience of application and cheapness. 



Copper Sulphate .— At the head of the list stands copper sulphate, a 

 cheap, effective fungicide, commonly known as bluestone. This is the 

 active and most essential ingredient of Bordeaux mixture. Concentrated 

 solutions of it cannot be used alone on foliage because of their caustic action. 

 In winter on dormant trees it is sometimes used for fungous troubles, about 

 two pounds being dissolved in a barrel of water. A weaker solution — 1 



Efficiency of Bordeaux Mixture on Potatoes. 

 Not Sprayed. 1 



One Row 



pound in 200 gallons of water — may be used on foliage in summer when 

 fruit is well matured and it is not desirable to use sprays like Bordeaux 

 mixture, which leave a residue. The bluestone may be quickly dissolved 

 by pouring boiling hot water over it. When one is not hurried it may be 

 dissolved by suspending in a loose sack in the water. It dissolves slowly 

 if simply thrown in the water and allowed to settle. 



To avoid to some extent the delays involved in dissolving bluestone it 

 is well to buy a finely powdered grade now manufactured for the making 

 of fungicidal preparations. 



Bordeaux Mixture. — A standard formula for the preparation of this 

 valuable mixture is the following: 



Bluestone 4 pounds 



Fresh lime 4 pounds 



Water 50 gallons 



i Courtesy of New York Agricultural Experiment Station, Geneva, N. Y. 



