Pomona College Journal of Entomology 



Volume II DECK M BE R 1910 Number 4 



THE CITRUS MEALY BUG 



{Pseudococcus citri) Kisso. 



UY E. o. ESSIC. 



Horticultural Coniniissioner of Ventura Count)-, California. 



GENERAL HISTORY AND DISTRIBlTIOX IX SOUTHHRX CALII'ORXIA. 



It is claimed by good authorities that the mealy bug first made its 

 appearance in this State on the Granger Place, in the Paradise Valley, just 

 north of National City, and that it spread from this locality to the adjoining 

 country. That it came from Florida is very probable, having been intro- 

 duced with nursery stock about the year 1880. To-day, only a remnant of 

 the old Granger orchard is left, but the mealy bug has a firm hold upon 

 many citrus groves in San Diego County. Sometime near the year 1904 

 this pest made its first appearance on the large Sweetwater Ranch at Bonita, 

 :ind has been a source of trouble ever since. A recent trip, by the writer, 

 to this locality revealed the fact that, in spite of much that has been accom- 

 plished by predaceous and parasitic insects, the mealy bug still plays an 

 important part in many large orchards, and in some the pest is very bad. 



In Orange County, the mealy bug has been known to exist in limited 

 numbers since the year 1898 in a few localities, but only during the past 

 few years, has it become a menace. It is now generally distributed but is 

 still scattering. 



The same conditions exist to-day in Los Angeles County. Here it 

 may be found in nearly every city greenhouse and scattered over a large 

 citrus growing territory, but not so serious as in San Diego or in \"entura 

 Counties. The process of distribution has been long and slow, and only a 

 very accurate tree to tree inspection can reveal the extent of the infestations. 



Few counties have ever suffered from the attacks of this pest, as ha^ 

 \'entura County. It was first observed in a greenhouse at Santa Paula, dur- 

 ing the year 1897, and was introduced on common greenhouse plants. For 

 many years it was never noticed in the citrus orchards, and when it did 

 ap])car in these orchards, it was regarded as a harmless greenhouse scale, 

 which could not thrive out-of-donrs. It took just 12 years for it to become 

 adapted and generally distributed, and then it threatened to ruin the entire 



