-88 INTERNATIONAL CONGRESS OF VITICULTURE 



combination of high temperature and moist air, which favors the development 

 of fungous diseases and makes their control difficult or impossible. 



Even Eureka and Berkeley have two months of almost complete absence 

 of rain and two more months when the rain is too scant to keep the air moist 

 for injuriously long periods. The summers in these localities, in fact, are 

 about as free from rain as in Ukiah and Redding, where all grapes succeed 

 admirably. Lack of heat is a sufficient cause for failure at Eureka but at 

 Berkeley, where the heat is ample for early varieties, the presence of frequent 

 summer fogs is sufficient to make their crops very uncertain. These fogs 

 militate against grape growing to an increasing degree, as we go north from 

 San Francisco, but their effect decreases gradually as we go south. Grapes 

 are grown in favored spots within a few miles of the ocean from Santa Cruz 

 south, but much trouble is experienced in controlling the Oidium. 



Winter Killing. 



The killing of dormant vines by cold is practically unknown in California. 

 A thoroughly dormant vine is seldom hurt by temperatures above 10 F., 

 unless it is of a tender variety or growing in very wet soil. Where the tem- 

 perature falls to 5 F. or lower, most varieties will be killed to the ground 

 unless protected. Such temperatures do not occur in California, except at 

 high elevations where the summers are too cool for grape growing. In more 

 northerly and easterly localities, such winter temperatures may occur even 

 where the summer temperature is favorable. In such localities, vinifera 

 varieties may be grown if protected with straw or soil during the winter. 

 Autumn killing occurs occasionally in nearly all parts of California, especially 

 in the wide plains of the interior. It is due to excessively late growth of the 

 vines, which maintains them in a susceptible condition until the first autumn 

 frosts. It occurs most commonly in vineyards of two or three years of age, 

 growing in rich moist soil. Younger vines are shallower rooted and the dry- 

 ing of the upper soil causes them to become dormant earlier. The drain of 

 the crop on the vital activities of bearing vines has the same effect. In all 

 cases it can be prevented by appropriate cultural methods which insure the 

 dormancy of the vine before November. 



Extent of the Industry. 



The vineyards of California covered in 1912 about 385,000 acres. Of this 

 total, about 180,000 acres were producing wine grapes. Roughly, 50 per cent 

 of the wine was produced in the great interior valleys, including most of the 

 sweet wines; 35 per cent was produced by the valleys and hillsides of the 

 Coast ranges, including most of the dry wines; the remaining 15 per cent 

 was produced in Southern California and included both sweet and dry. 



The raisin-grape vineyards covered about 130,000 acres, of which about 

 90 per cent were in the San Joaquin Valley, 7 per cent in the Sacramento, and 

 3 per cent in Southern California. 



The shipping-grape vineyards are reckoned at 75,000 acres, distributed 

 about as follows: 40 per cent in the Sacramento Valley, 40 per cent in the 

 San Joaquin, G per cent in Southern California, and 4 per cent in the Coast 

 ranges. 



