10 kepoet of search for enemies of citrus white fly. 



Description. 



Although the citrus white fly is known to attack several species 

 of plants, its special importance as a pest is owing to its injury of 

 citrus trees, in which the infestation is confined to the leaves. The 

 insect as commonly seen on trees is of the appearance of a small, 

 thin, transparent or gi'eenish-white scale entirely devoid of wings. 



In the earlier stages of development, as hatched from the egg, it 

 possesses three pairs of short, stubby legs and somewhat resembles 

 in general appearance a small louse or mite. So small is the insect 

 at this time and so transparent is it that only the closest observation 

 will reveal its presence to the naked eye. In fact, persons unac- 

 customed to close observation might easity examine aji infested leaf 

 without discovering the presence of these young insects. This is 

 the only time in the life of the immature insect in which it is able to 

 move about the plant. After hatching from the egg the minute 

 larva crawls about the leaves until it finds a situation suitable to its 

 taste. This found, it inserts its elongate threadlike mouthparts into 

 the leaf and then settles down to remain in this position until full 

 grown. The juice of the leaf is extracted through this threadlike 

 mouth. To allow growth, the hard outer skin of the young insect 

 is cast off from time to time. The legs are lost with the first molt, 

 so that in the later stages of development the insect is entirely without 

 the power of locomotion. 



With the third molt the insect passes from the so-caUed larval con- 

 dition into the pupal stage (PI. I). This is the last stage of develop- 

 ment and the one in which the insect is most commonly noticed. At 

 first thin and so pale gi'een as to be almost transparent, it becomes 

 thickened and opaque on approaching maturity. WTien almost 

 mature a bright orange spot appears on the back and later two purple 

 spots toward the anterior end. The insect at this time is about one- 

 sixteenth of an inch long or practically the size of the head of a 

 pin. These puiple spots are the eyes of the adult and appear from 

 three to eight days before the same is fully mature. When fully de- 

 veloped the pupa case splits down the back, allowing the adult to 

 come out. 



The adults are light orange-yellow in color and possess four wings, 

 which enable them to fly about the tree or from one tree to another 

 (PI. II). Tills is the only stage in which the white fly possesses much 

 activity, and were it not for the winged adults the mechanical con- 

 trol of this species would be quite easily accomplished. The eggs are 

 deposited on the lower surface of the leaves. An individual female 

 will average about 125 eggs during life. Usually many thousands of 

 eggs are deposited on a single leaf, the leaf presenting an appearance 

 as if sprinkled with grains of dust. 



