100 DISEASES OF ECONOMIC PLANTS 



are absent, this treatment may be modified in the light of 

 what is said on preceding pages. 



1. Employ methods 6, p. 22, and 9, p. 23. 



2. Apply a cleansing spray No. 3, p. 20. 



3. Use protective sprays No. 4, p. 20 : 1st, before 

 blossoms open ; 2d, after petals fall ; 3d, three or four 

 weeks later; 4th, about five weeks after the third; 5th, 

 about three weeks later ; 6th, about three weeks later. 



Bordeaux Injury to Apples 



Ever since the first trials of Bordeaux mixture upon the 

 apple some injury has been noted upon both leaves and 

 fruit, due to this mixture itself, the amount of injury 

 differing with different varieties, and with the weather 

 conditions. 



The injury may first appear a few days after spraying 

 or may be delayed for weeks, showing first on the fruit as 

 small, round, black specks, which later become rough and 

 russeted, and in severe cases distorted and badly scarred. 

 Such fruit does not keep well, becoming mealy or soft. 

 Upon the leaves brown dead spots are caused, often 

 followed by yellowing and fall of leaf. Blossoms are 

 killed, and the lives of visiting bees may be endangered. 

 These effects are worse in wet weather, also when large 

 amounts of copper sulphate are used than with smaller 

 amounts. 



This injury is far less than the fungous injury avoided 

 by use of the mixture, but should be reduced to a mini- 

 mum by spraying only when needed, giving less mixture 

 to those varieties which possess fungous resistance, and 

 to those varieties which prove most susceptible to Bor- 



