SPRAYING 263 



done before the disease is apparent. Some years we may 

 spray for a disease that does not develop seriously, but the 

 profits on the years when diseases are bad will usually 

 be much more than enough to pay for the apparent loss 

 of labor. However, there are very few years when spraying 

 does not give some benefits. 



Another essential in spraying for fungi is thoroughness. 

 If Paris green is put on a potato plant, even if only part 

 of the leaves are hit, the potato bugs may be poisoned. 

 If the poison is there, the bug will probably eat a poisoned 

 leaf tomorrow if he does not get one today. But when 

 we spray for fungi, only those leaves that are hit are 

 protected, and the unsprayed leaves furnish a place for 

 the disease to enter. 



238. The Preparation of Bordeaux Mixture. Several 

 strengths of the spray are used, as follows: 



Copper sulfate Two, three, four, five or six pounds. 

 Quicklime An equal number of pounds. 

 Water -50 gallons. 



For plants with tender foliage, two pounds of lime and 

 two of copper sulfate are used; for apples and pears, 

 about three to four pounds of each; for potatoes, six pounds. 

 The copper sulfate is dissolved and the lime slaked 

 separately. The copper sulfate is then diluted with nearly 

 all the water before the lime is added. If the concentrated 

 solutions' of lime and copper sulfate are put together, 

 they form a thick, curdled mass that will not stir up readily 

 when the water is added. The mixture is all right if either 

 the lime or the copper sulfate is diluted before adding 

 the other, or each may be diluted with half the water. 

 The former method is usually most convenient. 



