THE GRAPE PHYLLOXERA IN" CALIFORNIA. 7 



The date when these replants were procured is not specified, but was 

 probably about 1864 or 1865. Before the date of replanting the 

 phylloxera had infested the S'onoma Creek district and had spread 

 to Napa County. 



In 1859 a horticultural exhibit was held in the agricultural hall 

 just completed that year at Sacramento, and the records of the State 

 Agricultural Society mention exceptionally good exhibits of grapes 

 by progressive fruit growers. The eastern grape Catawba is twice 

 mentioned. 



From another report (4, p. 29-30) we learn to what extent the 

 eastern varieties of grapes were grown prior to 1875 in El Dorado 

 County. No mention is made of earlier dates, but it is more than 

 probable that the European grapes were already supplanting the 

 eastern ones, judging by the few of the latter type which were 

 planted in later years and which to-day are found only in family 

 vineyards and gardens. This report, written by Mr. Gr. G. Blan- 

 chard, commissioner of the State board of viticulture, further stated 

 that what was true of El Dorado County could also be said of 

 Nevada, Placer, Amador, Calaveras, Tuolumne, and Mariposa Coun- 

 ties. A passage reads : 



The proportions and kinds (grapes) growing, taking one hundred as the sum, 

 are as follows : Mission, or native grapes, sixty-eight ; Catawba and Isabella, 

 ten ; White Muscat, Muscatella, Malaga, six ; Tokay, Black Morocco, Malvoisies, 

 one ; Zinfandel, Riesling, two. The other thirteen are made up of numerous 

 other varieties, such as Sweet Water, Black July, Hartford Prolific, Cloantha, 

 and Concord, and some others. 



In this enumeration eastern grapes would represent approximately 

 23 per cent of the varieties grown. We thus see the important part 

 played by eastern varieties of grapes in the earliest plantings and 

 can conceive how the pest was introduced directly from its natural 

 habitat. 



ACCIDENTAL AND NATURAL SPREAD. 



Centers of infestation, when compared according to the modes of 

 dissemination which they engender, are of two kinds : Accidental 

 and natural. An accidental distribution center would be a nursery 

 which imported, unwittingly, phylloxera-infested grapes, propagated 

 the vines, and by so doing bred the insect and disseminated it with 

 the sale and shipment of these vines. The same is true when vines 

 are procured from phylloxera-infested districts. For new plant- 

 ings or replants, such a center would be the infested locality in Napa, 

 from which the Zinfandel vines were the means of introducing the 

 pest into a locality as yet free from it. In turn, the Orleans Hill 

 vineyard became a natural distributing center because the insect 

 by its natural increase and habit spread to other parts of the same 

 vineyard or even to other vineyards of the district. 



