File:The American rose annual (1922) (18134164716).jpg

Title: The American rose annual
Identifier: americanroseannu1922amer (find matches)
Year: 1916 (1910s)
Authors: American Rose Society
Subjects: Roses; Roses; Roses; Rose culture
Publisher: Harrisburg, Pa. : The Society
Contributing Library: UMass Amherst Libraries
Digitizing Sponsor: UMass Amherst Libraries

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INSECTS THAT HUNT THE ROSE 91
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There are in the eastern United States three common species of sawflies, the larvse of which feed on rose foliage. THE THREE ROSE SLUGS The American Rose Slug (Endelomyia rosae Harris).— This rose slug is a native American insect and is widely distrib- uted throughout the eastern United States, but is more abundant in the northern part of its range. The parent four-winged flies (Fig. 2) are deep shining black in color and about one-fifth inch in length. They appear on the rose bushes soon after the leaves open and may be found until the bushes are in full leaf. The female is provided with a sharp ovipositor with which she inserts her eggs into the tissue of the leaf between the upper and lower epidermis. The eggs hatch in ten days to two weeks, and the young slugs feed mostly at night, skeletonizing the upper surface of the leaves. The slugs are at first greenish, but later become opaque yellowish. They become full grown in two or three weeks. When mature the slug descends to the ground and there at the starts, and the spring forms develop on the rose. It has the same pronounced color varieties as Macrosiphum rosse, being either pink or green. On this account, and because of a simi- larity in size, these two species are often confused with each other, though the jet-black cornicles of Macrosiphum rosx make a distinguishing feature, as do structural differences discernible under the microscope. The winged forms migrate to the potato (and other annuals) where the simimer gen- erations are developed. Dispersing over the potato field, these insects carry the disease known as "potato mosaic" from sick plants to healthy ones. In the fall there is a migration back to the rose. Control.—While on the rose, the potato aphid should yield to any treatment that will control Macrosiphum rosse. Such treatment previous to the spring migration not only benefits the rose but, in certain localities, the potato crop as well. Fortunately, from the standpoint of rose-growers, potato mosaic assumes its greatest economic importance in localities which, for the most part, are not in the "real" zone of the cultivated rose—that is in those districts in the north where seed potatoes are grown for the southern planter. Those interested in the relation of this aphid, common on rose, to the potato mosaic are referred to Bulletins 292 and 303 of the Maine Agricultural Experiment Station.— Edith M. Patch. Fig. 2. The American rose slug (Endelomyia rosae): a, adult sawfly; b, mature larva; c, work of larva on rose leaf; d, section of rose leaf showing location of egg near upper margin; e, egg in situ on bit of rose leaf. (After Chittenden.)

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