﻿Pomona College Journal of Entomology 



Volume II DKCKMBER 1910 Niimbei4 



THE CITRUS MEALY BUG 



( Psciiciucocciis citri) Ris.su. 



I'.v K. 1). JCssic. 



Horticultural Coniniis^iniKT uf \cntura County, California. 



GENERAL IIISTOKV A.Mi IHSTKI I'.l 'r l( i\ 1 .\ SOUTHERN CALIFORNJA. 



It is claimed b)' .ynod autlmritics that the mealy bug first made its 

 i.ppearancc in this State on the (iranger Place, in the Paradise Valley, just 

 north of National Citw 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, onl\- a remn;mt 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 plavs an 

 imiKirtant part in many large orchards, and in some the pest is vcr\' 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 e.xist to-day in Los Angeles County. Mere 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 N'entura 

 Counties. The process of distribution has Ixcn long and ^low, and only a 

 very accurate tree to tree iiisf^eetinii can rerea! the extent of the infestations. 



Few cdunties have ever suffered from the attacks of this |)est. as h;is 

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

 ing the year 1807, and was introduced on common greenhouse ]ilants. I'or 

 many years it w;is never noticed in the citrus orchards, and when it did 

 ;ippear in these nrchards. it \\a> regarded as a harmless greenhouse scale, 

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

 ;idapted and geiicridly distributed. an<l then it threatened to ruin the entire 



