. Cirtus fruits under irragation. Citrus fruits; Fruit-culture. 36 CITRUS FRUITS UNDER IRRIGATION § 24 Parasitic and predacious insects attack the yellow scale, but do not hold it in check. It is controlled by fumigation, like the other scales. 36, Purple Scale.—The purple scale is not so widely distributed in California as the black, red, and yellow scales, but where it does occur it yields less readily to control than those mentioned, since the eggs are more resistant to fumi- gation. Leaves, branches, and fruits are attacked and often become completely encrusted; usually only a portion of t
. Cirtus fruits under irragation. Citrus fruits; Fruit-culture. 36 CITRUS FRUITS UNDER IRRIGATION § 24 Parasitic and predacious insects attack the yellow scale, but do not hold it in check. It is controlled by fumigation, like the other scales. 36, Purple Scale.—The purple scale is not so widely distributed in California as the black, red, and yellow scales, but where it does occur it yields less readily to control than those mentioned, since the eggs are more resistant to fumi- gation. Leaves, branches, and fruits are attacked and often become completely encrusted; usually only a portion of the tree becomes so completely infested. The insects thrive on the interior, lower parts of the tree and it is here that injury is most apparent. When the scales infest the leaves, a marked yellowing of the leaves occur, and in severe cases many of the branches become leafless. The purple scale excretes no honeydew, but, like the red scale, it injures the host plant directly by sucking the juices from the tree. When scales are present on immature fruit they have a tendency to delay the coloring. Often a green spot is present about a scale while the rest of the surface of the fruit is yellow The purple scale is attached very firmly to the fruit, and is not removed easily by washing; in fact, ordinary brushing and washing has little effect. The adult female scale is an elongated, oyster-shaped body varying from ^ to J inch in length and is one-third as wide. The female is stationary. The scale covering varies in color from a reddish-brown to a rich purple. The male scale, before the adult stage is reached, is more elongated in proportion to its size, narrower, and much smaller than the female scale. It can readily be distinguished from the female. When adult, the male is a minute, two-winged insect. The eggs of the purple scale are oval in shape and pearly white in color. They are protected by the scale covering above and by a cottony layer beneath and are covered at all points
Size: 1307px × 1911px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectcitrusfruits, booksubjectfruitcultur
