96 SPRAYING CROPS 



growing, and finally become disorganized, shapeless, 

 juiceless masses, shriveled to one-half their proper 

 size and fit only to develop the spores of the destroy- 

 ing fungus. And the/ do produce these spores, which 

 are massed together in little black pustules scattered 

 over the surface of the withered skin. 



This Black Rot fungus is most destructive in 

 southern latitudes. As far north as northern Ohio arid 

 western New York it is much less virulent than in 

 Tennessee or the Carolinas. Like most fungous dis- 

 eases it develops with greater rapidity during damp, 

 hot weather, or when nights with heavy dews alternate 

 with hot days. 



Remedies Spray with the copper sulphate solu- 

 tion before the buds start, then with the Bordeaux 

 mixture four or five times, making the first application 

 when the first leaves are half-grown ; the second, when 

 the fruit has set, repeating the later sprayings at inter- 

 vals of about fifteen days. If disease persists so later 

 sprayings are necessary, substitute the ammoniacal 

 solution of copper carbonate for the last one or two 

 sprayings, to avoid spotting the fruit. 



An account of the development of the DOWNY 

 MILDEW or BROWN ROT of grapes has already been 

 given in the Introduction (pages 7-9). This disease 

 has been, in years past, extremely destructive over a 

 wide area ; and it attacks disastrously both the foliage 

 and fruit. In southern latitudes it is said to be most 

 injurious to the former. 



Remedies The Bordeaux mixture is a practical 

 and efficient preventive of this disease. Spray first a 

 week or ten days before the vine blossoms ; second, 

 as soon as the berries are well set; and third, about 

 three weeks later. In very wet seasons it may be 

 desirable to spray a fourth time, but this is seldom 

 done. 



