INSECTS
Fig. 98. The rosy apple aphis, Anuraphis roseus, on apple
A, a cluster of infested and distorted leaves. B, an adult stem mother. C, young apples dwarfed and distorted by the feeding of the aphids
males and females are unknown. In the warmer regions of the West Coast of the United States, species that regularly produce males and females every fall in the East continue without a reversion to the sexual forms.
Of the other two species of apple aphids that infest the buds in the spring, one is known as the rosy apple aphis (Fig. 95 C). The name comes from the fact that the early summer individuals of this species have a waxy pink tint more or less spread over the ground color of green (Plate 3), though many of the adult stem mothers (Fig. 98 B) are of a deep purplish color. The early generations of the rosy aphis infest the leaves (Fig. 98 A, Plate 3 A) and the young fruit (Fig. 98 C, Plate 3 A), causing the former to curl up in tightly rolled spirals, and the latter to become dwarfed and distorted in form.
The stem mothers of the rosy aphis give birth parthenogenetically to a second generation of females which are mostly wingless like their mothers; but in the next generation many individuals have wings. Several more generations now rapidly follow, all females; in fact, as with the green aphis, no males are produced till late in the season. The winged forms, however, appear in increasing numbers, and by the first of July almost all the individuals born have wings.
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