6 HYDROCYANIC-ACID GAS FUMIGATION IN CALIFORNIA. 



under any of the others. This is mainly due to the fact that directors 

 of the former class are likely to employ field men of inferior qualifi- 

 cations. Efficient fumigation at the present time means, for the 

 most part, that the men in the field performing the operations are 

 careful, conscientious, and reliable. Otherwise the work is likely to 

 be performed in a slipshod, hasty manner, along lines of least resist- 

 ance. Work of this character, combined with the element of guess- 

 work in deciding the dosages and proportions of chemicals to be 

 used, has been responsible for most of the unsuccessful results. If 

 perfectly reliable men are employed to carry on the actual work in 

 the field, using the most approved methods, success will be as marked 

 with one system as with another. 



The recent horticultural ordinances of Los Angeles, San Bernardino, 

 and Riverside Counties requiring fumigators to be licensed are a step 

 in the direction of more efficient results. Such ordinances offer a 

 means of debarring outfits which perform unsatisfactory work. 



EXTENT AND CHARACTER OF CITRUS ORCHARDS. 



The production of citrus fruits in southern California is confined to 

 the narrow stretch of land south and west of the Sierra Madre Range, 

 extending from Santa Barbara on the north to the Mexican border. 

 Although citrus plantings are located here and there throughout this 

 territory, in reality only a small proportion of the land capable of 

 cultivation is devoted to this industry. The most prominent centers 

 of production (see fig. 1) are in the foothills region and lower land of 

 the San Gabriel Valley; the corresponding regions of the San Ber- 

 nardino Valley, including the Redlands-Highland, Riverside, and 

 Corona districts, and the coast region of Orange and Los Angeles 

 Counties. Regions of smaller production are found in southern 

 Santa Barbara and Ventura Counties, in the San Fernando Valley, 

 and in western San Diego County. 



The groves vary in size, the majority probably averaging between 

 5 and 15 acres. Some fruit growers have from 50 to 100 acres or 

 more, while a few fruit companies control from several hundred up 

 to about 3,000 acres. The trees for the most part are budded varie- 

 ties which average less than 20 feet in height. In some districts a 

 few groves of seedling trees 30 to 35 feet in height still exist. The 

 trees in most of the groves, especially those of more recent planting, 

 are regularly arranged, averaging from about 22 to 24 feet apart. 

 Some of the older groves are less uniform, either because they were 

 not arranged after the " block" system, or, if so, additional alternate 

 rows of trees were in terse t, which broke up the continuous open space 

 between two rows of regularly set trees, thus rendering it confusing 

 as well as difficult to work freely therein. 



