116 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



tracted rains. In bad seasons all varieties, without exception, are 

 subject to its attacks. Those esteemed as particularly hardy and free 

 from it in one locality succumb to it in another, or even in the same 

 locality another year. On the whole, the varieties reported most free 

 from it are Scuppernong, Norton's Virginia, and Ives's Seedling. 

 Almost the entire loss from Mildew must be attributed to Feronospora 

 viticola, since, as above stated, Uncinula spiralis does serious in- 

 jury only in a few restricted districts. 



(For distribution and severity in United States, see map. ) 



THE BLACK-ROT. 



Two hundred and twenty-eight persons reported the presence of 

 Black-rot, 



The territory over which Phoma uvicola is reported includes the 

 chief vine-growing regions of the United States, and coincides with 

 the Mildew district, save that no rot is reported west of the Rocky 

 Mountains, except doubtfully in one instance, and but very little 

 north of latitude 43°. In some districts this fungus has been under 

 observation for more than twenty years, and in many, during the last 

 decade, it has done serious and increasing injury. It usually at- 

 tracts attention about the time the grapes are beginning to color, or 

 a little earlier, and in very warm, wet seasons may within a week or 

 ten days destroy the whole product of a vineyard. As in the case of 

 Peronospora viticola, its growth is said to be greatly favored by 

 warm and wet weather, and entirely stopped by a protracted drought. 

 The Concord, Catawba, Isabella, Hartford Prolific, and Rogers- 

 hybrid varieties seem most subject to this rot, and the Delaware and 

 other light-colored or white varieties least; but no variety is entirely 

 free from its attacks, unless it be the Scuppernong, which is said to 

 be harmed by nothing. Many persons report all varieties equally 

 subject. Often those reported "iron-clad" and "rot-proof" in one 

 locality are said to be very badly affected in some other. 



(For distribution and severity in United States, see map.) 



SHRINKAGE OF YIELD IN OHIO. 



(See diagram.) 



The enormous shrinkage of the grape crop in 1881, 1883, and 1885 

 was due principally to three factors which cannot be separated — Rot, 

 Mildew, and the eliect of the previous severe winter. That freezing 

 was the factor least important may be assumed from the fact that 

 the winter of 1883-'84 was also severe, and killed or froze back many 

 vines, even hardy varieties, but did not prevent a good crop in 1884. 

 In 1882 the late summer and the autumn were dry. In 1883 it was 

 cold and wet in the spring, and there was long-continued wet weather 

 in June and July. In the summer and early autumn of 1884 Ohio 

 experienced one of the most widespread, prolonged, and severe 

 droughts ever recorded. In 1885 in Northern and Central Ohio the 

 spring was backward. June and July were warm and wet; August 

 and the first part of September were cold and wet. 



Mildew and Rot were unusually j)revalent and destructive in the 

 wet seasons of 1883 and 1885, taking the greater part of the crop in 

 many vineyards. In the dry seasons of 1882 and 1884 there was 

 comparatively little Rot or Mildew. The total product was 27,503,000 



