206 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



The only serious insect pests that have been noted are the vine 

 hopper and a species of thrips. 



The vine hopper seems at present confined almost entirely to one 

 locality, but it is possible that it may become as serious a pest as it 

 is in many other parts of California. The only method of control 

 which so far offers much chance of success can be applied effectively 

 only to vines which have a distinct trunk with all arms well off the 

 ground. 10 This offers another forcible reason for adopting the mode of 

 training recommended. 



The thrips have been found in large numbers on the vine blossoms. 

 So far as noted, no particular damage seems to have been done, as 

 their attacks were confined to the second crop. 



Several cases of dying vines were investigated. In some cases the 

 numbers of dying and dead vines was large. In all cases the trouble 

 seems to be due to mistakes in irrigation or cultivation. In the worst 

 cases the trouble seemed to be due to the shallow rooting of the vines 

 and their consequent sensitiveness to heat and drouth. 



This valley, like all of southern California, seems to be so far free 

 from phylloxera. It is advisable, therefore, that the present strict 

 quarantine should be maintained against all rooted vines from outside 

 the county and especially from eastern states and Europe. The exclu- 

 sion of unrooted cuttings, however, works an unnecessary hardship on 

 those growers who wish to plant or experiment with varieties which 

 cannot be obtained in the county. There is very little danger from 

 cuttings grown in California and this danger can be eliminated by 

 disinfection under the direction of the horticultural quarantine officer. 



Handling the Grapes. The profitable production of grapes in 

 Imperial County at present and probably in the future can be carried 

 on only by the methods of intensive culture. Wholesale, careless 

 methods may in some regions yield a profit in growing wine grapes 

 or raisin grapes, but the conditions for these industries are not at 

 present favorable in this region. Fine early table grapes that can be 

 placed on the eastern market in prime condition will command high 

 prices. Inferior grapes or grapes which spoil before they reach the 

 consumer are hard to give away and can never yield a permanent 

 profit. 



Every reasonable effort, therefore, should be made to produce only 

 the choicest fruit. An extra expenditure of $25 to $50 per acre is 

 justified if the salable value of the crop is increased $100 or $150 per 

 acre. 



10 See Bulletin 198 and Bulletin 193, pp. 111-116, Agricultural Experiment 

 Station, Berkeley, California. 



