THE GRAPE PHYLLOXERA I2T 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. G. 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. 
