. Annual report of the Commissioner of Agriculture ... Agriculture -- New York (State). THE CONTKOL OF PLANT LICE ON APPLE TREES* H. E. HODGKISS and B. B. FULTON. Plant lice are among the most harmful pests of the apple. During recent years these insects have been very destructive in many orchards in the leading apple-growing sections of New York. The species of aphids which occur on this fruit are the green apple-aphis (Aphis pond DeG.), the rosy apple- aphis (Aphis sorbi Kalt.), the European grain-aphis (Sipho- coryne avenue Fab.), and the woolly apple-aphis (Schizon- eura lanigera Hausm.).
. Annual report of the Commissioner of Agriculture ... Agriculture -- New York (State). THE CONTKOL OF PLANT LICE ON APPLE TREES* H. E. HODGKISS and B. B. FULTON. Plant lice are among the most harmful pests of the apple. During recent years these insects have been very destructive in many orchards in the leading apple-growing sections of New York. The species of aphids which occur on this fruit are the green apple-aphis (Aphis pond DeG.), the rosy apple- aphis (Aphis sorbi Kalt.), the European grain-aphis (Sipho- coryne avenue Fab.), and the woolly apple-aphis (Schizon- eura lanigera Hausm.). The most injurious forms are the green apple-aphis and the rosy apple-aphis. The woolly apple-aphis is abundant only in occasional years. NATURE OF INJURY. Injuries from plant lice result chiefly from the extrac- tion of plant juices by the insects which feed upon foliage (Plate XXI, fig. 1) and fruits. Young, tender, growing twigs and succulent sprouts afford the most con- genial conditions for aphids and on those they multiply very rapidly. The lice choose by preference the lower and more dense portions of the trees and are less often found in the top- most branches. The work of the aphids dur- ing May and June is especially destructive since it occurs during the period when next year's fruit buds are forming and when the vigor of the trees is also required for the development of the young apples of the current season's crop. If favorable conditions exist for the rapid increase of the pests the leaves become curled (Fig. 39) and the development of the young. Fig. 39.— Leaves curling from aphis attacks. .Reprint of Circular No. 2:3, March 4, 1913. [365]. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original New York (State). Dept. of Agriculture; New York State Agricultural Experiment Station; Cornell Universit
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