. Bulletin. Forests and forestry. Insect Enemies of Shade Trees and Shrubs 43 • per cent, of them turn brown and fall from the tree. The writer has observed several cases where small or medium sized Camperdown elms were in a dying condition, apparently from the repeated attacks of this insect. The adult of the elm leaf-miner is a black rather wasp-like insect about % inch long (Fig. 15). These dusky winged insects emerge from the ground where they have spent the winter in the latter part of May. They ily to the leaves of the elm where they may often be seen in immense numbers. Here the females
. Bulletin. Forests and forestry. Insect Enemies of Shade Trees and Shrubs 43 • per cent, of them turn brown and fall from the tree. The writer has observed several cases where small or medium sized Camperdown elms were in a dying condition, apparently from the repeated attacks of this insect. The adult of the elm leaf-miner is a black rather wasp-like insect about % inch long (Fig. 15). These dusky winged insects emerge from the ground where they have spent the winter in the latter part of May. They ily to the leaves of the elm where they may often be seen in immense numbers. Here the females lay their eggs, placing them well down into. Fig. of the elm saw fly, much enlarged. (G. W. Herrick, Cornell BuU. 333.) slits made in the upper surface of the leaf by their saw-like ovipositors. The eggs hatch in from 6 to 10 days and the minute lai^ae immediately begin to burrow through the parenchyma of the leaf, mining out irregular galleries (Fig. 14) and causing the upper and lower epidermis of the leaves to die and turn brown. Several larvae often occur in each leaf and in such cases the leaf is nearly entirely destroyed and falls from the tree. When the larvae are full grown, which occurs about July 1st, they break through the epidermis of the leaf, fall to the ground and burrow into this for a distance of about an inch. Here they construct for themselves a brown parchment-like cocoon in which they spend the rest of the summer and all of the next winter, the adults emerging the following 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 State University College of Forestry at Syracuse University. Syracuse, N. Y.
Size: 2149px × 1162px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectforestsandforestry
