252 MANUAL OF FRUIT DISEASES 



grapes. In the spring spores from acervuli in the old lesions 

 bring about the first infections. 



Moisture and the proper temperature are essential to the 

 development of the pathogene. It is said that a poorly-drained 

 soil also favors the fungus. 



Control. 



Until recently little has been done in American vineyards 

 to prevent anthracnose, although its control is well understood 

 in Europe. Recommendations based on the results of careful 

 experimentation follow : (1) prune out and burn all diseased 

 wood ; (2) spray' dormant vines with lime-sulfur, diluted one to 

 nine ; (3) spray the vines with bordeaux mixture, as for black- 

 rot of grapes as follows : (a) when the shoots are eight to twelve 

 inches in length ; (b) just before the flower-buds open ; (c) just 

 after the blossoms fall ; (d) ten to fourteen days later ; (e) and 

 again in ten to fourteen days. The addition of two pounds of 

 resin-fish-oil soap to fifty gallons of the spray mixture in the 

 last two applications is advisable on account of the increased 

 adhesiveness of the fungicide which results. 



For the dormant spraying lime-sulfur may be replaced by 

 a fungicide of the following formula : 



Iron-sulfate, 13f lb., or 6| Ib. 



Sulf uric-acid (commercial) 7 oz., or 3i oz. 



Hot water, 3i gal. 



This mixture of iron-sulfate and sulfuric-acid has been 

 successfully applied in Europe. It is objectionable, however, 

 for it is unpleasant to prepare and to use because of the corro- 

 sive action of the sulfuric-acid. A four per cent solution 

 of sulfuric-acid has also been used as a substitute for other 

 dormant fungicides. 



