CALIFORNIA VINE OR ANAHEIM DISEASE CAUSE AND NATURE 5 







parts of Napa and Sonoma counties by Professors Viala and Serib- 

 ner. 



That in some localities whole vineyards have died in a short 

 time, is because in the first place the cause and the augmenting 

 factors mentioned, were very pronounced; in the second place the 

 vines stood on a uniform soil, made uniform growth and therefore 

 died off uniformly. On account of the richness and great uniformity 

 of all alluvial soils the trouble has been greatest in valleys. Mount- 

 ain soils are more "spotted," and for this reason the disease has ap- 

 peared only in spots so far, wherever conditions were most favor- 

 able. 



It has been called by some the vine-top disease, also in some 

 of the earlier reports the statement is made, that the disease first 

 appears at the end of the canes. This is wrong ; tops and roots are 

 attacked simultaneously, although generally in a different degree. 

 If the roots were sound, there would be a bushy growth of healthy 

 suckers coming from its base. As it is, if these come at all, they 

 only come sparingly and sickly from the beginning. True, the 

 symptoms of the disease are first visible on the young foliage. 



To ascertain this more clearly, I root-pruned during the winter 

 several vines, which had made vigorous growth the preceding sum- 

 mer, but which had shown signs of attack in yellow spots appear- 

 ing on their leaves, by digging a trench around them about three 

 feet deep and four feet from their bases. As the soil was shallow 

 but rich and the vines extended their roots horizontally in all di- 

 rections twenty feet and more, the root-pruning was thorough. I 

 also root-pruned some healthy vines in the same manner. Exam- 

 ining the roots of these vines the following summer I found the 

 young root-growth on the healthy ones strong and sound, but on the 

 attacked ones small and sickly, similar to the top-growth. 



If we are anxious to give a name to the disease, I believe "Par- 

 alysis of the Grape Vine" is the most appropriate one. I shall point 

 out a few similarities between human paralysis and the California 

 vine disease : In both vital activity, which manifests itself in man 

 principally in voluntary motion, and in the grape vine in the growth 

 of new wood, is impaired, although without any outward sign on 

 the main body. In both the young are less subject to an attack than 

 the old. Like a human the vine sometimes is affected on one side 

 only, while the other side remains healthy at least for some time. 

 A predisposition to attack is increased in man by rich living, so 

 vines on rich ground are more susceptible to the disease than vines 

 on poor ground. In human paralysis there are different degrees of 

 attack, so vines are attacked differently, some more severely than 

 others. 



It is a curious fact that cuttings taken from only slightly af- 

 fected vines will grow fairly well as long as the vines are young, 

 the soil moisture is not exhausted and so the cause of the disease 

 does not exist, but as soon as this appears again the vine has an- 

 other attack during the latter part of the summer and then fails to 

 make proper growth the following spring. 



In grafting an old Muscat vine three years ago, which had suf- 



