150 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



chlorophyll properly, is due to an excess of soluble lime carbonate in 

 the soil, and is intensified by cold, dampness and the susceptibility of 

 the variety. 



The most serious of these two classes of diseases, which affects the 

 vines, is the Anaheim, or, as it is sometimes called, the California Vine 

 Disease. Notwithstanding that it has been the subject of continuous 

 investigation for over fifteen years its cause is still quite obscure. Even 

 the characterization and detection of the disease are so uncertain that 

 vineyards, which after several years of observation by the most ex- 

 perienced investigators have been pronounced infected, have later been 

 declared free. This has led to such a diversity of opinion that while 

 one expert claims that the disease exists in every vineyard in the 

 State, another would have us believe that no such disease exists at all, 

 and 'that all cases of dying vines can be ascribed to one or other of the 

 recognized vine diseases. 



Neither of these extreme views seem to explain completely the 

 observed facts. While many cases of supposed Anaheim have proved 

 to be nothing but Phylloxera, root-rot, vine-hopper, drought, etc., there 

 still remain a large number of unexplained cases. 



In some cases the symptoms are practically identical with those of 

 some of the "physiological" diseases which affect vine diseases in 

 Europe. Typical cases of Eougeot .have been noted in Contra Costa 

 County, of Brunissure in San Joaquin, and of Folletage in Fresno, 

 Kings, and other counties. In Sonoma County the disease of Red-leaf, 

 which has some analogy with Anaheim, has been studied by Mr. 0. 

 Butler. An account of these diseases may be found in Bulletin 168, 

 entitled ' * Observations on Some Vine Diseases in Sonoma County. ' ' 



In a general way, as these troubles are due to soil and climatic con- 

 ditions which weaken the vine, they are to be combated by cultural 

 methods which tend to invigorate. Shorter pruning, thorough culti- 

 vation, irrigation or drainage, and fertilization will in most cases be 

 effective in curing vines which are not too far gone. 



Many cases have been brought to the attention of the station during 

 the last two years, in which vines which were apparently healthy the 

 previous year have failed to bud out in the spring, or budded out 

 weakly and very late. The cause, in most cases, seemed to be some 

 injury to the vines during the growing season of the previous year. 

 This cause was in many cases the attacks of vine-hoppers. Black 

 Prince vines growing in Tokay vineyards have very often been killed. 

 This seems to be because the vine-hoppers, having a special fondness 

 for this variety, congregate in large numbers on such isolated vines. 

 Whenever the hoppers are sufficiently abundant to cause the dropping 

 of the leaves in summer, the vine fails ' to ripen its wood properly. 



