UNIVERSITY OF CALIFORNIA, 



COLLEGE OP AaHICULTtmE, AGRICULTURAL EXPERIMENT STATION. 



E. W. HILGABD, DIRECTOR. 

 BERKELEY, CALIFORNIA. 



AUGUST 26, 1901. 

 PROFESSOR E. W. HILGARD, 



Director of Agricultural Experiment Station. 



DEAR SIR: In accordance with your directions we have examined the 

 vineyards of Santa Clara with the object of determining the cause of 

 the failure and death of a large number of vines in parts of that county 

 during the last three years. It is not possible at present to give a com- 

 pletely satisfactory explanation for such serious and widespread damage 

 as has occurred, but our observations seem to prove conclusively two 

 propositions: First, that the dying vines exhibit symptoms differing 

 materially from those shown by the vines in Southern California which 

 were destroyed by the Anaheim disease; and, second, that whether or 

 not there be some u unknown influence " at work, as suggested by Mr. 

 Newton B. Pierce, the real, determining factor is the deficiency of rain- 

 fall during the years 1897-1900. 



Area and General Character. The dying of vines without perceptible 

 adequate cause during the last three years has by no means been con- 

 fined to the west side of the Santa Clara Valley. Similar cases have 

 been reported and investigated over a wide area extending from the 

 northern part of Sonoma County, to the western and southern parts of 

 the Santa Clara Valley, and including nearly all the older vineyard 

 districts within these limits. The only peculiarity of the cases on the 

 west side of the Santa Clara Valley is their number, extending in many 

 cases to every vine in a vineyard. The distribution of the injured and 

 dead vines is not in any of the cases examined such as to suggest an 

 infectious parasitic cause. In some instances single vines failed and 

 died sporadically where the main bulk of the vineyard was in fair con- 

 dition, and a dead vine was usually surrounded by vines which were 

 apparently healthy. 



Nature of Injury. In most of these sporadic cases examined the dying 

 vine was found to have been severely injured in some way, usually by 

 cutting off large branches at the pruning and thus causing large wounds. 

 Vines of this kind when split open were found to be more or less 

 decayed in the middle, and many were quite hollow. In a report made 

 to you last year on the same subject this decay of the interior of the 

 trunk was suggested as the cause of death in some cases. This year, 

 however, though in some vineyards the hollow vines have continued to 



