Small Fruits 



121 



Upon the leaves the disease appears considerably earlier 

 than upon the fruits. Here it produces tan-colored spots 

 about 3-8 mm. in diameter, many or few according to the 

 severity of the infection. In or near the centers of the older 

 spots, upon the upper surface of the leaves, are seen the 

 nearly microscopic pycnidia which are often arranged in 

 concentric circles. 



On the young shoots the spots are somewhat more reddish 

 and are often cracked longitudinally, 

 but otherwise they are as upon the 

 leaves. 



This rot is much more prevalent 

 in warm, humid weather than in 

 dry times, and a few days of muggy 

 weather may so favor the growth 

 of the causal fungus as to develop 

 an epidemic, which may in turn be 

 checked by a dry spell. Often the 

 disease appears in distinct waves 

 during the season, each wave cor- 

 responding to a climatic condition 

 favorable to infection and usually 

 lagging behind such favorable con- 

 dition a period of 8 to 14 days, the 

 time necessary after infection for 

 the disease to become conspicuous 

 enough to attract the attention of 

 the vineyardist. 



While the Scuppernong occa- 

 sionally shows a few spots upon leaf or berry and the blossom 

 is sometimes affected, this variety is practically immune. 



To prevent the inroads of black-rot, thorough, clean cul- 

 ture should be practiced. All mummified fruit should be 

 burned to avoid infection. Keep the ground free from 

 sprouts and all other growths and i:)ermit no weeds or grass. 

 Cover crops are beneficial. Plow early so as to cover all re- 

 maining leaves and berries that Ijear the hibernating fungus. 



- Grape black- 

 Original. 



