THE MONTHLY BULLETIN. 



143 



^They are usually found only upon the foliage — the under sides of the 

 leaves being favorite feeding places. 



The distribution of the ordinary and indestructive members of this 

 family is wide throughout the State, but the citrus infesting white 

 fly is exceedingly limited and every possible means are being exer- 

 cised by the State Commission of Horticulture to completely eradicate 

 Aleyrodes citri, the only species now present. 



The control of the white flies is the same as recommended for 

 scale insects, and consists of spraying and fumigation. 



Ladybird beetles and hymenopterous parasites prey upon these 

 insects. 



THE CITRUS WHITE FLY. 



Aleyrodes citri Riley and Howard. 

 (Figs. 125, 126.) 



General Appearance. — The adult white flies are about one tenth of 

 an inch long; have yellow bodies and opaque wings covered with a 

 fine white powder. The males have a characteristic tuft on the under 

 side of the abdomen. The pale yellowish-green eggs are suspended on 

 short stalks. The first hatched young have legs and antennae like a 

 small scale insect, but after moulting these disappear and the body 

 becomes flat, greatly resembling a soft scale. 

 The development of the insect takes place in 

 the flattened shell which gradually becomes 

 raised, showing segmentation and yellowish 

 color. The adult emerges by breaking through 

 the top of the skin. 



Life History. — The wnnter is passed in the 

 miature larval stage on the under sides of the 

 leaves. Early in the spring the pupae appear 

 and in ]March and April the adults emerge. 

 The eggs are deposited upon the foliage, the 

 larvae beginning to hatch in about three weeks. 

 The first hatched have legs and appendages 

 and greatly resemble a young scale. They soon 

 settle to feed and after several months move 

 no more until the adult stage is reached. There 

 are several overlapping broods each year. 



Distribution. — At the present time this pest is known to exist only 

 in the city of Marysville where it infests yard trees. Continuous con- 

 trol measures have reduced it to almost a minimum. The white fly 

 lias been known to exist at Oroville and near Bakersfield, but in both 

 places seems to have been exterminated. It has been found in a number 

 of localities in the city of Sacramento, but all infested trees have been 

 promptl}' destroyed. 



Fig. 126. — Adult citrus 

 white fly {Aleyrodes citri 

 R. & H.). Enlarged fif- 

 teen times. (After Quayle. 

 Courtesy Cal. Exp. Sta.) 



