22 MISC. PUBLICATION 4 9 8, U. S. DEPT. OF AGRICULTURE 



CALIFORNIA RED SCALE 



(Aonidiella aurantii (Mask.)) 



The California red scale is a serious pest of citrus fruit in many 

 parts of the world, but it is found chiefly in regions having a semiarid 

 climate like that of California, Australia, and South Africa. At the 

 stage of development most likely to be found on fruit on the market 

 it is bright red to black, rather than reddish brown as in the case of 

 the Florida red scale. In gross appearance, except color, the two scales 

 are very similar. 



Fumigation is recommended for the control of this insect. 



(See 81, 94, 100, 131, 132.) 



CHEWING-INSECT INJURY 



When citrus fruits are young they are sometimes attacked by grass- 

 hoppers, katydids, and other chewing insects, which eat away the rind 

 over areas of varying size on any part of the fruit. Some of these 

 injuries are probably so severe that they cause the fruit to drop ; others 

 heal over, producing a roughly circular, or sometimes oblong, smooth 

 scar which at the edges is sharply sunken below the level of the rest 

 of the rind (see pi. 18, D). These sunken scars are rarely discolored. 



Grapefruit and oranges may be affected, as well as lemons. 



CITRUS RUST MITE RUSSETING 



(Phyllocoptruta oleivorus (Ashm.)) 



OCCURRENCE, SYMPTOMS, AND EFFECTS 



The citrus rust mite occurs in the Gulf States and the West Indies 

 and to a slight extent in California. It is not a serious pest of citrus 

 fruit anywhere in the last-named State. Although it may attack all 

 commercial varieties of citrus, most of the damage is done on grape- 

 fruit and oranges. The mite is a minute member of the spider family, 

 which sucks the juice from both leaves and fruit and thereby injures 

 them. Several types or degrees of the injury are recognized. 



(1) Injury produced by very early infestation. This is characterized 

 by slight, scattered, more or less crisscross or star-shaped brown etch- 

 ings or russeting of the rind near the stylar end of the fruit. It is 

 sometimes mistaken for copper-spray russeting or for the effect of 

 rubbing while the fruit is on the tree. This type of blemish is found 

 mostly on oranges. 



(2) Injury caused by somewhat later but severe infestation and 

 known as "sharkskin" (pi. 5, B) . Practically the entire surface of the 

 rind of fruits affected by this blemish becomes slightly roughened, ab- 

 normally thick, and of a pale grayish or silvery appearance. Young 

 fruits are often stunted in growth ; fruits of normal size are commonly 

 light in weight and contain less than the usual amount of juice. 

 Sharkskin is much lighter in color than melanose. This tyrje of citrus 

 rust mite russeting, which is found chiefly on grapefruit and oc- 

 casionally on lemons and limes, is not often seen on the market. It 

 does not spread in transit, but the damage done by it to the market 

 value of the fruit is considerable, since much of what would other- 

 wise be classed bright fruit must be placed in the russet class solely 



