Manual of vegetable-garden insects . is oftenfound in greenhouses, where it infests the calla lily, carnation,rose, violet, oleander and many others. It has also been re-corded from tulip, pansy, hollyhock, tobacco, peppermint, rapeand several ornamental plants. It is also sometimes found inthe summer on apple, pear and lilac. The spinach aphis may pass the winter either in green-houses or on its food plants out of doors, where the winters arenot too cold, or in the egg stage on the peach, plum, cherry,apricot, sand cherry and choke cherry. In the last case, theeggs hatch shortly before the bu
Manual of vegetable-garden insects . is oftenfound in greenhouses, where it infests the calla lily, carnation,rose, violet, oleander and many others. It has also been re-corded from tulip, pansy, hollyhock, tobacco, peppermint, rapeand several ornamental plants. It is also sometimes found inthe summer on apple, pear and lilac. The spinach aphis may pass the winter either in green-houses or on its food plants out of doors, where the winters arenot too cold, or in the egg stage on the peach, plum, cherry,apricot, sand cherry and choke cherry. In the last case, theeggs hatch shortly before the buds burst in the spring and thestem-mothers are ready to begin reproduction when the blossomsappear. They are wingless and of a pinkish color. In thesecond generation the ])lant-lice are for the most part wingless,but instead t)f being pink, are pale yellowish green and usuallymarked with three indistinct darker stripes on the the third generation, most of the lice acquire wings. They 106 MANUAL OF VEGETABLE-GARDEN INSECTS. are then greenish with the head, thorax and a large spot on theabdomen black. These winged forms leave the tree and flyto their various herbaceous food plants where they found coloniesof young. When the lice have survived the winter on weeds or vegetables, reproduction is resumedas soon as new growth starts in thespring. They multiply rapidly andthe plants soon become covered withthe lice. The wingless forms foundon the summer food plants have thebofly a uniform greenish yellow,without the darker lines found onthe forms on the peach, or plum(Fig. 66). When the plant becomesFig. 66. —Wingless viviparous crowded, winged forms (Fig. 67) are female spinach aphis (X 11). , i i • i • pi produced which migrate to new feed-ing grounds. The insects are most destructive to spinachlate in the season when the cooler weather prevents the rapidmultiplication of their predaceous and parasitic enemies,although they may become troublesome at any time. In thef
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1918