248 STATE BOARD OF HORTICULTURE. 



The following species of this genus infest citrus trees in 

 California; 



(1) Red scale — Aspidiotus aurantii, Maskell. 



(2) Yellow scale — Aspidiotus citrinus, Coquillett. 



(3) Oleander scale — Aspidiotus nerii, Comstock. 



(1) Red Scale. 



A circular, flat scale, known hy the popular name of " red 

 scale," from the color of its shell. 



Scale of female is light gray, quite translucent. Female 

 light yellow in adolescent stages; as it reaches maturity 

 becomes brownish. Viviparous. 



Ventral view ol insect. Red Scale on leaf. 



Scale of male resembles female, except that it is only one 

 fourth as large. Male light yellow, thoracic band brown; 

 eyes purplish black. 



This insect is the worst enemy to citrus culture in California. 

 It attacks the trunk, branches, leaves, and fruit. So far no 

 effective parasites are known to attack it, excepting predaceous 

 insects, which do not increase rapidly enough to check its 

 progress. 



Treatment. — Rosin solution (formula No. 1), and gas treat- 

 ment (formula No. 4). 



(2) Yellow Scale. 



A small yellow scale, infesting citrus trees in the San Gabriel 

 Valley, Los Angeles, Sacramento, Oroville, and Marysville. 



