The Elm Leaf Beetle
Life history: The elm leaf beetle, Fig. 10, is annually causing the
defoliation of thousands of elm trees throughout the United States.
Several successive defoliations are liable to kill a tree. The
insects pass the winter in the beetle form, hiding themselves in
attics and wherever else they can secure shelter. In the middle of
May when the buds of the elm trees unfold, the beetles emerge from
their winter quarters, mate, and commence eating the leaves, thus
producing little holes through them. While this feeding is going on,
the females deposit little, bright yellow eggs on the under side of
the leaves, which soon hatch into small larvae or grubs. The grubs
then eat away the soft portion of the leaf, causing it to look like
lacework. The grubs become full grown in twenty days, crawl down to
the base of the tree, and there transform into naked, orange-colored
pupae. This occurs in the early part of August. After remaining in
the pupa stage about a week, they change into beetles again, which
either begin feeding or go to winter quarters.
Remedies: There are three ways of combating this insect: First, by
_spraying the foliage_ with arsenate of lead in the latter part of
May while the beetles are feeding, and repeating the spraying in
June when the larvae emerge. The spraying method is the one most to
be relied on in fighting this insect. A second, though less
important remedy, consists in _destroying the pupae_ when they
gather in large quantities at the base of the tree. This may be
accomplished by gathering them bodily and destroying them, or by
pouring hot water or a solution of kerosene over them. In large
trees it may be necessary to climb to the crotches of the main limbs
to get some of them. The third remedy lies in gathering and
_destroying the adult beetles_ when found in their winter quarters.
The application of bands of burlap or "tanglefoot," or of other
substances often seen on the trunks of elm trees is useless, since
these bands only prevent the larvae from crawling down from the
leaves to the base and serve to prevent nothing from crawling up.
Scraping the trunks of elm trees is also a waste of effort.
1. Egg cluster, enlarged. 1a. Single egg, greatly enlarged. 2. Young
larva, enlarged. 3. Full grown larva, much enlarged. 4. Pupa, enlarged.
5. Overwintered beetle, enlarged. 6. Fresh, brightly colored beetle,
enlarged. 7. Under surface of leaf showing larvae feeding. 8. Leaf eaten
by larvae. 9. Leaf showing holes eaten by beetles.]
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Tree Studies
How To Identify Trees
Group I The Pines
The White Pine (pinus Strobus)
The Pitch Pine (pinus Rigida)
The Scotch Pine (pinus Sylvestris)
Group Ii The Spruce And Hemlock
The Norway Spruce (picea Excelsa)
Hemlock (tsuga Canadensis)
Group Iii The Red Cedar And Arbor-vitae
Red Cedar (juniperus Virginiana)
Arbor-vitae; Northern White Cedar (thuja Occidentalis)
Group Iv The Larch And Cypress
The European Larch (larix Europaea)
Bald Cypress (taxodium Distichum)
Group V The Horsechestnut, Ash And Maple
The Horsechestnut
The White Ash (fraxinus Americana)
Sugar Maple (acer Saccharum)
Silver Maple (acer Saccharinum)
Red Maple (acer Rubrum)
Norway Maple (acer Platanoides)
Box Elder (acer Negundo)
Group Vi Trees Told By Their Form: Elm, Poplar, Gingko And Willow
American Elm (ulmus Americana)
Lombardy Or Italian Poplar (populus Nigra, Var Italica)
Gingko Or Maidenhair Tree (gingko Biloba)
Weeping Willow (salix Babylonica)
Group Vii Trees Told By Their Bark Or Trunk: Sycamore, Birch, Beech,
Blue Beech, Ironwood, And Hackberry
The Sycamore Or Plane Tree (platanus Occidentalis)
Gray Or White Birch (betula Populifolia)
American Beech (fagus Americana)
Blue Beech Or Hornbeam (carpinus Caroliniana)
Hackberry (celtis Occidentalis)
Group Viii The Oaks And Chestnut
White Oak (quercus Alba)
Black Oak (quercus Velutina)
Red Oak (quercus Rubra)
Pin Oak (quercus Palustris)
Chestnut (castanea Dentata)
Group Ix The Hickories, Walnut And Butternut
Shagbark Hickory (hicoria Ovata)
Mockernut Hickory (hicoria Alba)
Black Walnut (juglans Nigra)
Group X Tulip Tree, Sweet Gum, Linden, Magnolia, Locust, Catalpa,
Dogwood, Mulberry And Osage Orange
Tulip Tree (liriodendron Tulipifera)
Sweet Gum (liquidambar Styraciflua)
American Linden (tilia Americana)
The Magnolias
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Informational