10 
FUMIGATION INVESTIGATIONS IN CALIFORNIA. 
EXTENT 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 through- 
out this territory, in reality only a small proportion of the land 
capable of cultivation is devoted to this industry. The most promi- 
nent 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 Bernardino Valley, including the Redlands-Highland, the 
Riverside, and the Corona districts; and the coast region of Orange 
FIG. 1,— Map showing principal localities in southern California where citrus fruits are produced. 
(Original.) 
and Los Angeles counties. Regions of smaller production are found 
in southern Santa Barbara and Ventura counties, in the San Fer- 
nando Valley, and in western San Diego County. 
CITRUS PESTS. 
INSECT ENEMIES OF CITRUS FRUITS, AXD THEIR DISTRIBUTION*. 
The larger number of the pests most injurious to citrus fruits in 
southern California belong to the Coccidae, a group of insects popu- 
larly known as scale-insects. Among the scale-insects which are 
a For a general description of the California citrus-fruit industry, see Bulletin 123, 
Bureau of Plant Industry, United States Department of Agriculture 1 , which may be 
obtained for 20 cents from the Superintendent of Document.-. Government Printing 
Office, Washington. D. C. 
