376 



BIOLOGICAL CONTROL 



character and simplicity of the indigenous fauna with its paucity of 

 hyperparasites and other competing forms, provide a biological 

 association exceptionally favourable to the introduction of beneficial 

 species which meet with but few obstacles in the struggle for existence. 



Later Work in California. Following the introduction of 

 Vedalia cardinalis, already alluded to. biological control in 



Fig. 9.'}. A typical insectary used for rearing Crijptohvmns. San 

 Gabriel Valley Pest Control Association, Lamanda Park, 

 California. (Photo supplied by courtesy of Professor H. S. 

 Smith.) 



California had, for a time, a somewhat chequered record. Grave 

 mistakes were made by unscientific enthusiasts, large sums of 

 money expended with no appreciable results, and world travel 

 undertaken by agents of the State with disappointing consequences. 

 But as H. S. Smith remarks (1926), this is past history, and the 

 enthusiasm of the public for biological control is now tempered 

 by a far better knowledge of its limitations. The worst pests of 

 the citrus groves are Coccidae, and following the control of the 



