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UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



without the other arms or shoots being affected." Vines planted in 

 "deep, cool, damp soils" are subject to this trouble, especially when 

 heat follows heavy rains. In dry soils the Folletage also occurs. In 

 both cases it is due to a rupture of the equilibrium between the trans- 

 piration of the leaves and the absorption of the roots. The resemblance 

 between the effect of the Folletage and that of the Red-leaf disease is 

 not a very close one. The Red-leaf disease is apparently not fatal in a 

 single season, if ever. Like the Folletage, however, it affects the vines 

 with greatest intensity and suddenness during July and August, and 

 more frequently partially than wholly. The death, either total or 

 partial, of the affected shoots does not follow the attack in the great 

 majority of cases. In some cases of Folletage, the foliar characteristics 

 are very similar to those of vines affected with the Red-leaf disease, if 

 we may judge from plates 17, 18, and 19 given as illustrations of this 

 disease in Bulletin No. 2 of the Division of Vegetable Pathology, U. S. 

 Department of Agriculture. 



Resemblance between the Rougeot and the Red-leaf Disease. -The Rou- 

 geot is considered by some authors as a mild form, so to speak, of the 

 Folletage, and attributable to the same cause. The Rougeot affects 

 vines as sporadically and irregularly as the Red-leaf disease. Its foliar 

 characteristics remind one of those of the Anaheim, or the Red-leaf 

 disease. Vines affected with Rougeot generally recover. 



Resemblance between the Red-leaf and the California (or Anaheim) 

 Vine Disease. For a description of this disease the reader is referred 

 to Pierce's memoir on the subject.* To describe the disease, even in 

 the most summary manner, is not necessary in the present publication. 

 The California vine disease and the Red-leaf disease are sufficiently 

 different from each other, in their salient characteristics, to be easily 

 distinguished without resorting to details. The reader will find, in the 

 following comparison, a sufficient proof of the distinctiveness of these 

 two diseases: 



Anaheim Disease.^ 



The disease is cumulative. 



The newly-formed leaf either remains 

 green or is striped yellow or red, accord- 

 ing as the grapes are white or red. (loc. 

 cit., page 142.) 



As a rule the leaves fall from the base of 

 the canes first, (loc. cit., page 45.) 



The roots are decayed, (loc. cit., page 57, 

 et suiv.) 



Grapes dry and remain on the vine, or fall 

 off, but not very frequently, (loc. cit., 

 page 53.) 



A diseased vine shows the disease most 

 generally on all its shoots, (loc. cit., 

 page 79.) 



Red-leaf Disease. 



The disease is not cumulative. 



The newly-formed leaves either dry with 

 deformation (leaves just expanded) or a re 

 paler than normally and convex (leaves- 

 two or more nodes from the apex). 



The leaves fall from the apex first. 



The roots are healthy. 



Grapes are mottled with livid, sunken 

 spots. 



The number of shoots affected is variable, 

 though rarely total. 



*Bull. No. 2, Div. Veg. Path., U. S. Dept. 

 fN. B. Pierce: "California Vine Disease, 



Agr. 



" loc. cit. 



