The Shipley Collection of Scientific Papers Volume 100

The Shipley Collection of Scientific Papers Volume 100

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1904 edition. Excerpt: ...Careful search was made at the roots of the infested plants, but no trace of any aphides could be found. It is, therefore, apparent that this Strawberry Aphis passes the winter solely in the egg stage on the leaves, and does not migrate. One noticeable feature is that where there is an excessive and dense foliage, the Aphis is most abundant. On opening some of the plants sent from Hereford, literally thousands of lice and winged fly and masses of white exuviae were found. Nevertheless, there were numbers according to Mr. Bickham on some young Paxtons, which had only three or four leaves per plant. No doubt dense, close growth helps them in bad weather, but we are sure to find it on plants of all ages and stages. From plants kept under observation during the greater part of a year, I feel sure the whole life-cycle is passed on the Strawberry. That it may occur on the wild strawberry and other plants is possible, but at present we have no evidence that it does so. Infection may easily be spread by nursery stock, by means of the eggs attached to the leaves passing unnoticed. The Aphis not only prevented many trusses from bringing their fruits to a marketable size, but many of them settled on the fruits themselves, sheltering between the fruit and the calyx. The attack lessened as the fruit got ripe and the leaves hardened, and few were noticed at the end of picking. None were noticed by Mr. Bickham on the worst plantation after picking, but they continued on the young plants A New Species. This Aphis is undoubtedly new. The only species it might be is Koch's Siphonophora fragariae. It cannot be that species for the following reasons: --(i.) The eyes are black instead of being red. The pupae have the wing-cases all green, not with dark apices...show more

Product details

  • Paperback | 116 pages
  • 188.98 x 246.13 x 6.1mm | 222.26g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236739566
  • 9781236739568