INSECTS AFFECTING CITRUS FRUITS 455 



are not abundant enough to injure the tree seriously they may 

 cause considerable loss by their presence on the fruit. Atten- 

 tion is usually called to the pest by the presence of small light 

 yellowish spots on the leaves. The scale of the female is 

 almost circular in outline, very flat, and about one-thirty-sec- 

 ond to one-sixteenth of an inch in diameter. The scale of the 

 male is more elongate. This insect increases in numbers so 

 rapidly that although it is attacked by several natural enemies 

 it is necessary to take active measures early to control it when 

 it gains a foothold in the orchard. Fumigation is the most 

 practical remedy. 



The yellow scale, a variety of the red scale, is very similar in 

 appearance and habits to the red scale, and is only distin- 

 guished from it by its lighter color. It confines its attacks to 

 the leaves and fruit, seldom attacking the twigs or branches. 



The red scale of Florida, C. aonidum, is similar in appearance 

 to the red scale of California, but the waxen cover is heavier 

 and darker, usually reddish-brown or almost black with a 

 whitish spot in the center. It is of little importance as an 

 enemy of citrus trees, but is often a serious pest in greenhouses. 



The Purple Scale (Lepidosaphes becki). In general ap- 

 pearance this scale is very much like the oyster-shell scale that 

 occurs on the apple trees. It attacks all parts of the trees, 

 the leaves, branches, trunk and fruit frequently becoming 

 entirely covered by the pest. It may cause the leaves or fruit 

 to drop, or may even kill part of the tree, but it seldom kills 

 the entire tree and so is not as serious a pest as the red scale. 

 It occurs in destructive numbers throughout the citrus regions 

 of Florida and the Gulf states and in certain sections of Califor- 

 nia. The female insect occupies only the anterior portion of the 

 scale, the posterior portion being full of eggs and growing to 

 meet the requirements as more eggs are produced. The young, 

 soon after hatching, make their way from beneath the pro- 

 tecting scale, settle on the plant, and begin secreting the waxy 

 substance that is to form their scale-like covering. It is 

 toward the destruction of these younger scales that the 

 orchardist must direct his attention, for the old insects are so 

 well protected that it is difficult to kill them with any ordinary 



