44 THE BITTER ROT OF APPLES. 



(3) Is early spraying more advantageous than late spraying in the 

 treatment of this disease? — No evidence was obtained from the exper- 

 iments calculated to prove that early spraying is more advantageous 

 than late spraying. The later sprayings — that is, those made after the 

 apples were half formed — in our estimation were the most effective. 

 The early spraying resulted in a severe rusting of the fruit during one 

 year. The tissues of the young fruits developed very slowly under 

 the spots where the fungicide covered the epidermis, and rusted and 

 misshapen fruits resulted in many cases. Thick-skinned varieties like 

 the Ben Davis showed this rusting to a marked extent. The exact 

 explanation for this rusting as a result of spraying with Bordeaux 

 mixture is still to be determined. 



(4) Are any other fungicides superior to Bordeaux mixture in the 

 treatment of this special malady? — The Bordeaux mixture is, as far as 

 our tests go, certainly superior to any of the other fungicides used, 

 i. e., ammonium copper carbonate and potassium sulphide. 



Summing up the evidence from our own spraying operations as 

 well as those of others, the following recommendations can be made 

 at this time : 



(1) For spraying to prevent bitter rot use the standard Bordeaux 

 mixture, i. e., 6 pounds of copper sulphate^ 4 pounds of lime, and 50 

 gallons of water. 



(2) Spray at least once before the buds open. This spraying of the 

 trunks and branches should be thorough, so as to reach any possible 

 spores about to form cankers or coming from cankers. 



(3) Spray during the middle of the summer, beginning about the mid- 

 dle of June, and continue several times until the fruit is almost ripe. 

 Should the attack come very late in the summer, use the ammonium 

 copper carbonate, so as to avoid damaging the fruit for the market, 

 because of a possible lime deposit from the Bordeaux mixture. 



In addition to these sprayings aimed especially at bitter rot, it is 

 necessary to spray with Bordeaux mixture to which Paris green or 

 some arsenical poison has been added just after the petals have fallen 

 and again ten days to two weeks later. This is directed against apple 

 scab, codling moth, and leaf -eating insects, as well as bitter rot and 

 leaf blight. 



SUMMARY AND RECOMMENDATIONS. 



The facts presented in the foregoing pages may briefly be summarized 

 as follows: 



(1) The bitter rot or ripe rot is one of the most serious diseases of 

 apples. The loss due to this disease in 1900 was estimated (for the 

 United States) as $10,000,000. It is one of the most difficult diseases 

 to control and is constantly on the increase. 



(2) The bitter rot is due to a fungus, Glomerella rufomaculans (Berk.) 



