APPENDIX. 141 



considered in the above figures, would grade as "No. 1" fruit. As 

 is well known, however, the fungus grows rapidl}' after the fruit is 

 packed, hence the rigid adherence to our arbitary distinction. 



As shown by the table, the best results were obtained from the 

 use of a combination of Bordeaux mixture and Paris green — a fact 

 which would indicate a possible fungicidal value for Paris green. 

 That this value is slight, however, was shown by some trees sprayed 

 with arsenite only. 



The modified ea^c celeste^ while less effectual than Bordeaux 

 mixture in preventing scab, was also found to injure the foliage 

 unless used with caution. The fruit also was made somewhat 

 rusty, the epidermis apparently being injured by the ammonia. 



The relative value of the different materials used may best be 

 illustrated by the following diagram, the shaded portion represent- 

 ing the per cent, of fruit free from scab : 



1. Xot sprayed. 



Eau Celeste. 



Bordeaux Mixture , 



Bordeaux Mixture, 

 and Paris Green. 



A Brief Retrospect. 



For the benefit of those who have not received previous reports, 

 it may be well to give a brief resume of the results obtained from 

 three seasons' experiments. 



We have seen that apple scab is caused by a parasitic fungus 

 which attacks the leaves and young twigs as well as the fruit, and 

 that the growth of the tree may be seriously checked. Spraying 

 the trees with certain compounds of copper has been found an 

 effective means of holding the disease in check, — the increase of 

 salable fruit, as a result of spraying, often amounting to 50 per 



cent. 



Indications point strongly to the value of spraying early in the 

 season, before the blossoms open, and of repeating the application 

 four or five times during the season. 



The best results have been obtained from the use of Bordeaux 

 Mixture, prepared as follows : 



6 pounds copper sulphate (Blue Stone), 

 4 pounds quick lime, 

 40 gallons water. 



