236 THE CHIEF SOUTHERN AGRICULTURAL CROPS 



The Linsecomii varieties have all originated with 

 Mr. Munson in Texas. They are especially adapted 

 to southwestern conditions, though they succeed 

 well in most other 'parts of the South. They con- 

 tain some very fine table varieties. Owing to their 

 wide range in season of ripening, they have con- 

 siderably extended the Southern grape season. The 

 adaptability of these kinds to tropical conditions has 

 not yet been determined. 



Grapes are subject to a great variety of insect 

 pests and fungous diseases. Owing to the impor- 

 tance of the vine industry in Europe and to the fact 

 that it has been three times seriously threatened 

 with annihilation, owing to the importation of Ameri- 

 can diseases (powdery mildew, downy mildew, and 

 Phylloxera), attention was early called to these 

 troubles, and they have been more exhaustively 

 studied and published on than the diseases of any 

 other cultivated plant. The resulting mass of liter- 

 ature is so enormous as to be absolutely bewildering. 

 Only the more important troubles can be touched on 

 here. For practical purposes it is only necessary to 

 know that most of the fungous diseases and leaf-eat- 

 ing insects can be held in check by persistent spray- 

 ing with Bordeaux mixture and Paris green. This 

 treatment is strongly recommended wherever grapes 

 are grown in the humid regions. The first spray- 

 ing should always be given before the buds open. 



Powdery mildew ( Uncinula') is a superficial fun- 

 gus that forms a white coating over the leaves, 

 fruit clusters, and young stems. It is very injuri- 

 ous to the European varieties, but rarely does much 



