VARIOUS VINE TROUBLES 



367 



The Bordeaux Mixture and other copper preparations are 

 sometimes useful upon grape-vines, as will be cited in the chapter 

 on plant diseases. 



Coulure. A frequent misfortune of the vine, and for which 

 no remedy is yet known, is coulure, a term signifying the failure 

 of the fruit to set or to remain on the cluster. This occurs in 

 varying degrees from the loss of a few berries to the almost 

 complete clearing of fruit from the stem. It is worse with some 

 varieties than others and in some localities than others. The 

 trouble is believed to arise from various causes. 



There is, also, occurring with more or less frequency, a red- 

 dening and death of the vine leaves, supposed to be identical 

 with the trouble known to the French as "rougeole." The leaves 

 show light-colored spots at first, which afterward turn red 'and 

 finally involve the whole leaf or cane, and sometimes the whole 

 vine. It usually occurs in mid-summer, and is not necessarily 

 fatal in its effects. 



Root Knot. An evil occurring on the main stem of the vine, 

 generally near the surface of the ground, is an excresence of 

 woody character commonly called "black knot." There has been 

 much discussion as to the cause of this abnormal growth, without 

 full agreement among observers. Some attribute the knots to 

 injuries to the stump in cultivation, others to outbursts of sap 

 which the short pruning system does not give top growth enough 

 to dispose of, and to various other causes. This is analogous to 

 the "crown knot" of fruit trees which will be mentioned in the 

 chapter on plant diseases. 



Anaheim Disease. There has prevailed for several years in 

 California a mysterious disease of the vine known as the "Ana- 

 heim disease," because its evil work first appeared in that vicinity. 

 It destroyed many thousand acres of vines and led to the aban- 

 donment of grape growing in some regions in southern California. 

 The fullest statements concerning its performance can be found 

 in Bulletin No. 2, U. S. Department of Agriculture, Division of 

 Vegetable Pathology, by Newton B. Pierce, 1892, and Farmers' 

 Bulletin No. 30, 1895. Fortunately during recent years the trouble 

 has been less aggressive but neither its nature nor satisfactory 

 treatment has been fully demonstrated. The latest available 

 information concerning it and other troubles of the vine can be 

 had by application to the University Experiment Station at 

 Berkeley. 



