b HYDROCYAXIC-ACID GAS FUMIGATION IX CALIFORXIA. 
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 maimer, 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 approYed methods, success will be as marked 
with one system as with another. 
The recent horticultural ordinances of Los Angeles, San Bernardino, 
and Rixerside 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 
cultiYation is deYoted 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, RiYerside, 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 groYes vary in size, the majority probably aYeraging between 
5 and 15 acres. Some fruit growers haYe from 50 to 100 acres or 
more, while a few fruit companies control from seYeral hundred up 
to about 3,000 acres. The trees for the most part are budded Yarie- 
ties which aYerage less than 20 feet in height. In some districts a 
few groYes of seedling trees 30 to 35 feet in height still exist. The 
trees in most of the groxes, especially those of more recent planting, 
are regularly arranged, aYeraging from about 22 to 24 feet apart. 
Some of the older groYes are less uniform, either because they were 
not arranged after the " block" system, or, if so, additional alternate 
rows of trees were interset, 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. 
