THE GRAPE PHYLLOXERA IK" CALIFORNIA. 11 



nels. For this reason the early plantings give an idea of how the 

 insect could have been spread before its presence was suspected. 



PRACTICAL METHODS EMPLOYED TO ARREST THE SPREAD OF THE PEST. 



When the discovery of phylloxera in California was first made 

 known, the grape growers were already acquainted more or less 

 with the havoc it had produced in the vineyards of France, and a 

 panic spread throughout the different grape districts. It soon sub- 

 sided, however, when the vineyards were not being rapidly destroyed, 

 and even precautionary measures were overlooked. 



Of all the grape-growing counties, that portion of Alameda County 

 known as the Livermore Valley district evolved the best organized 

 system of quarantine measures, the aim of which was not to prohibit 

 the importation of vines into the county, but to have cuttings, as 

 well as rooted vines, thoroughly disinfected before they were per- 

 mitted to be planted. 8 



The disinfectant used was a commercial soluble phenol. Vines 

 were immersed for one-half hour in a solution of 1 part phenol to 60 

 parts water. Notwithstanding these precautions, vines were intro- 

 duced without the knowledge of the quarantine commission, and 

 there occurred three distinct centers of infestation from which the 

 pest was remarked to spread with the prevailing summer winds. 

 Two of these centers were planted originally with material from 

 San Jose, and the third with vines from St. Helena, in Napa County. 



DISTRIBUTION OF PHYLLOXERA IN CALIFORNIA. 



As far as has been observed, Stanislaus, Merced, Kings, and Madera 

 Counties, north of Tehachapi Pass, are free from phylloxera. South 

 of Tehachapi Pass it has not been found so far. Most of the counties 

 named have either enacted ordinances establishing prohibitive quar- 

 antine against the importation of grapevines or protective measures 

 subjecting vines to strict inspection and fumigation. 



The absence of infestation is without doubt not wholly due to 

 quarantine measures, which were enacted years after the pest had 

 many opportunities to be introduced, but more likely is due to the 

 combined conditions of climate and soil in these counties. 



The writers have made a personal investigation of the present status 

 of phylloxera infestation, and have tried to ascertain and estimate 

 approximately the damage caused to the viticultural interests. At 

 this late date, however, there is much difficulty in obtaining informa- 

 tion on which to base the estimate. Quite a number of vineyards have 

 been replanted, some as many as three times ; property has changed 

 hands, and the history of vineyards has been forgotten. Again, 



8 Data personally contributed by Charles A. Wetmore, formerly chief executive of the 

 State board of viticultural commissioners. 



