THE GEAPE PHYLLOXERA IN CALIFORNIA. 15 
At this time the phylloxera was known to exist more or less 
throughout the valley, and had been identified in different vineyards, 
but as yet its injury had not reached the advanced stage of noticeable 
characteristic phylloxera spots, was therefore little in evidence, and 
was not considered a prominent factor in connection with the de- 
struction of the vineyards. 
The following facts were brought out during the writers' investi- 
gations and have a direct bearing upon existing conditions in the 
Santa Clara Valley at that time : 
Extensive areas of a vineyard may be infested by phylloxera be- 
fore characteristic spots are noticeable; a lighter crop and a slight 
decline in vigor of growth are for some time the only apparent signs 
of injury. 
Infested vines change suddenly for the worse, becoming rapidly 
stunted in growth, or even dying, when influenced by unusual con- 
ditions either from lack or excess of moisture. 
Injured roots, functioning poorly under normal conditions of 
moisture, reproduce with difficulty fibrous roots, or feeders, to replace 
those which have been destroyed by the insect, and when subjected to 
drought they starve the vine. 
Excessive moisture, instead of benefiting injured roots, causes them 
to rot and hastens the death of the vine. 
For these reasons it is believed that the phylloxera was responsible 
for a far greater share of the destruction of the Santa Clara Valley 
vineyards than has been ascribed to it,. 
While Santa Clara and the southern counties have lost in acreage, 
a larger gain has been made at about the same period and later 
in other counties, especially those of Sutter, San Joaquin, and 
Fresno. Many vines throughout the State have been killed by 
phylloxera and not replanted; more have been grubbed out. and 
replanted, sometimes more than once, and it is estimated that the 
loss in these respects has been very considerable. 
Mr. George C. Husmann, pomologist in charge of viticultural 
investigations, Bureau of Plant Industry, United States Department 
of Agriculture, estimates the loss at 75,000 acres; Prof. F. T. Bioletti, 
of the viticultural department of the University of California, makes 
a similar estimate; and Charles C. Wetmore, for many years identi- 
fied with the board of State viticultural commissioners, considers 
this estimate conservative. 
VINEYARD DESTRUCTION. 
PROGRESS OF THE DESTRUCTION OF A VINIFERA VINE. 
According to conditions there is a great variation in the number 
of months or years that elapse between its original infestation by 
