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SHADE TREE INSECTS

- . +. LESSON NUMBER TEN - - -

es
PART I. 30 4!
BORERS Dwg
NOTE TO STUDENTS: It is important that the

Tree Surgeon should not only know when a tree needs his
technical skill in removing decay and repairing injuries,
but he should also be able to quickly detect the presence of
any agency liable to injure or kill the tree.

In the last lesson you studied the fungous and similar
diseases tending to injure or kill shade trees, but the in-
sects, one of the commonest causes of disease as there de-
fined, were considered of too great importance to be
treated at that time.

The present lesson is the introduction to this very im-

JOHN DAVEY portant subject, and will consider the borers, or those in-
“FATHER OF sects which burrow under the bark or into the harder parts
TREE SURCERY” Of the trees. Their habit of working entirely within the tree
makes them very hard to control, and they frequently

cause serious injury before even their presence is suspected within the tree.

The control of the borers is such a difficult problem that few entomo-
logists have given it the attention that it deserves; consequently, the litera-
ture on the subject is widely scattered, and much of it is very unreliable. For
this reason a full lesson will be devoted to this important subject, and the
other shade tree insects will be left for the next lesson. The fruit insects
will be considered under the subject of fruit growing.

The science of economic entomology, to which you are introduced in this
lesson, is so vast and so important that most of your information must come
from your text books and from the references furnished you. All that can be
done in the lessons is to consider a few of the more important and representa-
tive species, and those with which you are most liable to have to deal in your
future work as Tree Surgeons. By having a thorough understanding of these,
you will also be able to deal successfully with the other related species when
you meet them.

Copyright, 1914. The Davey Institute of Tree Surgery, Kent, Ohio.

S HAD E T KR E E INSECTS

INSECTS

1. The insects, or the six-legged animals comprising the Class
Insecta, are the most highly developed of the invertebrate animals.
They include the smallest of the walking animals, and a greater
variety of forms than all the rest of the animal kingdom com-
bined. Man can learn many valuable sociological lessons by a
careful study of some of these forms.

2. It has been estimated on good authority that fully ten
million species will be represented before the insect life of the earth
is fully explored. New species are being described and named at
the rate of about 10,000 a year, and the richest collecting grounds
have hardly been touched. The total number named is rapidly
approaching a million.

3. Fortunately but a very small part of these are injurious,
and many are beneficial. The American insects of special eco-
nomic importance would hardly reach a thousand, and a tenth of
these are responsible for the billion dollar loss sustained by the
United States each year. Even ten of them are responsible for a
loss each year greater than the total expense for the maintenance
of the United States Department of Agriculture and all the experi-
ment stations.

4. This will give you an idea of the enormous loss that these
pests are capable of inflicting, and will help you to see the great
importance of knowing the more important insects that work on
our shade trees.

5. To control these pests, you must know their habits, the
part of the trees attacked, the time when they are the most easily
killed, the proper remedy to use, and the effect of the remedy upon
the tree and upon the pest. This knowledge can come only by
thorough study, hard work, close observation, and practical experi-
ence.

6. It would be helpful at this time to consider the structure
and habits of the different types of insects, but this can be easily
secured from your text books and general references on the subject.

CLASSIFICATION

7. For convenience in studying them, the insects will be classi-
fied according to the nature of the injury which they inflict upon
the trees. But to a certain extent this will also classify them ac-

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THE DAVEY INSTITUTE OF TREE SURGERY

cording to orders and families to which they belong, for the rea-
son that similarity of habits means a similarity in structure, and
similarity in structure is the basis for the natural classification
used in grouping and naming insects.

8. Classed according to the nature of the injury they inflict,
the injurious insects fall into the following four classes:

Borers, or those insects that work under the bark,
either in the adult or larval stage, and the subject of this
lesson.

Leaf Feeders, or the insects that feed upon the leaves,
either in the adult or larval stage, and consume all or part
of the tissue of the leaves. This includes the eating in-
sects, the leaf miners, skeletonizers, case bearers, etc.

The Sucking Insects, or those that secure their food by
puncturing the tissue and sucking the juices, whether from
the bark, leaves or fruit.

The Gall Insects, or those that cause abnormal growths
on the different parts of the tree as a result of the injury
inflicted. This class contains representatives from nearly
every order of insects. It contains a great variety of
forms, of which comparatively little is known, especially
regarding the methods of control. They may affect the
leaves, twigs, bark, flowers, fruit or roots.

BORERS

g. From the nature of the injury they inflict, and their habit
of working under the bark or within the wood, the borers are the
most difficult, of the serious shade tree insects, to control. In some
cases the larve live within the tree for three or more years. This
makes it difficult if not impossible to study their habits, and also
protects them to a great extent from their natural enemies.

10. For the most part, the borers are scavengers, living on
dead or decaying wood, and are an efficient help to the saprophytic
fungi in reducing waste material to its natural elements, ready to
be worked over again by other living organisms. In this way
some of the borers are a great benefit.

11. Unfortunately, however, some of the borers, in working
in decaying trees, came too near to the living tissue, and so devel-
oped a taste for the fresher living wood. From these a few species

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SHADE T REE IN S E CTs

have developed which will attack and kill living trees, and in a few
cases species which will attack and kill or seriously injure trees in
apparently good health. In this they are very similar to the para-
sitic and saprophytic fungi. Many of them cannot cause injury
until they get started through a wound, or until the vitality of
the tree has been weakened by some other cause.

12. Among the borers you will find a smaller per cent. which
can successfully attack a tree in perfect health than in any of the
other classes of the injurious insects. In most cases the eggs are
laid upon the bark, and when the minute larva crawls out of the
shell it begins to burrow into the tree. The entrance is so small
that it is hard to find, and the larva is quickly buried where it can
carry on its destructive work unobserved. However, if the tree
is in vigorous health, when the robber reaches and injures the cam-
bium layer, this starts a flow of sap that drowns out the intruder.
In some cases the healing is sufficiently rapid so that the burrow
is closed faster than the larva can make it, and the pest is buried
in a grave of its own digging.

13. Anything tending to check the growth of the trees makes
it easier for the borers to become established, and, if sufficiently
abundant, to cause serious injury. Under the right conditions, a
few dying trees can produce borers in such vast numbers that
they cannot find enough dead or dying trees for their food; con-
sequently, they must attack healthy trees or perish.

14. Under city conditions, for this reason, you will meet with
serious injury done to shade trees by species that would be harm-
less under forest conditions, owing to the adverse conditions under
which these city trees must struggle for an existence. Keep this
thought in mind, therefore, both when working with the trees and
when studying the literature on insects. Many of these species
with which you will have to deal have, up to this time, been studied
only from the forester’s standpoint.

15. Remember, that city trees are very largely deprived of the
natural protection afforded the forest trees by the birds and other
natural enemies of the insects. Remember, too, that city trees
must frequently struggle against insufficient sunlight, food and
water. Their roots are also frequently buried beneath asphalt
pavements and cement sidewalks, which keep away the fresh water
and the invigorating gases brought down with the rain. City.
trees are also subjected to the severe slashing of the contractors

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THE DAVEY INSTITUTE OF TREE SURGERY

and linemen in laying foundations or pavements, and in stringing
telephone wires through the streets.

CONTROL

16. Although the borers do a great amount of injury to our
trees each year, very little thorough work has been done to deter-
mine satisfactory methods for their control. The problem is so
dificult, and the prospect of obtaining satisfactory results is so
small, that few entomologists have been tempted to undertake
the work. It is much easier to guess at the remedy, to advise a
remedy used for a similar insect, or to shift the responsibility alto-
gether and follow the recommendations of the earlier writers.

17. To judge correctly the value of the methods of control
generally in use today, it is necessary to trace these methods back
through the literature and see whether they are based upon care-
ful observations or experiments, or simply given first as a guess
and later quoted as a fact.

18. The following quotations of remedies suggested for the
control of the elm borer will serve as an illustration of the develop- ‘
ment of some of the remedies still in use:

19. 1905, Felt. “The badly infested portion should be cut
away and the grubs destroyed, and where a few are working in
living bark it might be well to remove the upper layers till the
grubs are nearly exposed, and then brush over the shaven surface
with strong kerosene emulsion or whale-oil soap solution, finally
covering the wound with a paste formed of a mixture of fresh cow-
dung and lime.”

20. 1893, Lintner. ‘‘Remove the outer bark from the entire
infested portion of the tree in the spring by shaving it down to
the inner bark until the first indications of the fresh burrows are
disclosed. A kerosene emulsion of good strength brushed over the
shaven surface would kill the insects, after which a coating of
some thick substance, as lime and cow-dung, should be applied to
prevent the splitting of the sap-wood from exposure to the sun,
drying winds or extreme weather.”

21. 1880. The use of kerosene emulsion as an insecticide was
discovered about 1880 by the United States Department of Agri-
culture, consequently is a recent addition to the remedies.

22. 1848. Robert (France). “Strips about two inches wide
were cut out of the bark from the large boughs down the trunk to

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SHADE TT R EOE INSECTS

the ground, and it was found that where the young bark pressed
forward to heal the wound and a vigorous flow of sap took place,
many of the maggots near it were killed; the bark which had not
been undermined was consolidated, and the health of the tree was
improved.”

23. Using this as a basis, he tried a more extensive experiment
by “paring off the whole of the rough outer bark from 2,000 elms
with a scraping-knife shaped like a spoke-shave. This operation
caused a great flow of sap in the inner lining of the bark, and the
grubs of the Scolytus beetle were found in almost all cases to perish
shortly after.”

24. 1842, London Botanic Society. A similar treatment was
given to elms encircling their garden in the Regent’s Park, London.
“Tt consists in divesting the tree of its rough outer bark, being
careful at the infested parts to go deep enough to destroy the
young larve, and dressing with the usual mixture of lime and cow-
dung.”

25. The “usual mixture” is probably the following ‘For-
syth’s Composition,” or a modification of it. The directions for
preparing this were given under oath at the Land Revenue office,
in Scotland Yard, the 11th day of May, 1791. They are as follows:

26. 1791, Forsyth (England). ‘Take one bushel fresh cow-
dung, one-half bushel lime rubbish from old buildings, one-half
bushel wood ashes, one-sixteenth bushel pit or river sand. The
last three are to be sifted fine before they are mixed. Then work
them well together with a spade, and afterward with a wooden
beater, until the stuff is very smooth, like fine plaster used for the
ceilings of rooms.”

27. Soapsuds or urine were used to make this “composition”
of the consistency of wet plaster or paint. The composition was
also valued as a filling for cavities in trees.

The following is still earlier, but along the same line:

28. 1629, Parkinson (England). ‘The canker is a shrewd
disease when it happeneth to a tree; for it will eate the barke
round, and so kill the very heart in a little space. It must be looked
into in time before it hath runne too farre: most men doe wholly
cut away as much as is fretted with the canker, and then dresse ity
or wet it with vinegar or cowe’s pisse, or cowe’s dung and urine,
etc., until it be destroyed and after healed againe with your salve
before appointed.”

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THE DAVEY INSTITUTE OF TREE SURGERY

29. In the following discussion
the remedies advised are based upon
experience and experiments, or have
been traced far enough back so that
we know they are the best that can
be given until more is known on the
subject.

LEPIDOPTERA

30. Very few of the butterflies
and moths comprising this order
have the habit of burrowing into
wood or the harder part of plants.
The three species considered below
represent the two families contain-
ing the more important of these
borers.

31. The injury they do is done
in the larva stage. These larve are
provided with well developed thoracic
legs, as well as five pairs of prolegs.

2 1. LEOPARD MOTH
Courtesy Connecticut Agr. Exp. Station. Family COSSID-. Species Zeuzera

Fig. 1 pyrina Fabr.
Leopard moth and its work. .
After W. E. Britton. 32. This European moth was

introduced into this country be-
fore 1880. It was first found in Hoboken, New Jersey, in 1881,
and has since spread up the Atlantic coast from New Jersey to
Massachusetts, causing very serious damage to the shade trees in
many of the cities. It has not been found far back from the coast,
nor in the country where the native birds are plentiful.

33. This moth is widely distributed in Europe, where it has
been known in the literature under the name of Zeuzera e@sculi
Linn.

34. Food Plants. In Europe it is reported as feeding upon
six species of shade trees, but in this country it has been found
feeding upon eighty-three different species of trees and shrubs. It
is most injurious to the elms, maples, horse chestnut, Ohio buck-

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S HA DE T EK EB E INS £ CTS

eye, beeches, birches, dogwoods, hickories, oaks and walnuts, in
the order named.

35. Symptoms. Dead, dying or wilting limbs, projecting
above leafy branches, or broken and hanging among otherwise
healthy trees, are the surest indications of the work of this borer.

36. Habits. The dirty white adults, appearing from May to
September, have a wing expanse of from 2% to 3 inches in the
female, but the male is not so large. The fore wings are covered
with numerous black spots. The under side of the body and the
legs are black. The upper side of the abdomen is black or striped
with black, and the thorax is spotted with six or seven black spots.
The females are large and sluggish. They have a three-jointed
ovipositor, with which the eggs are placed in cracks of the bark or
under bark scales.

37. ‘The males can be collected in great numbers around elec-
tric street lights, but the females are poor flyers and do not fre-
quent the lights so abundantly.

38. The eggs, 400 to 800 in number, are laid in crevices in the
bark of the trunk or limbs, singly or several in a place. On hatch-
ing, the larve crawl to the top of the tree and enter the smaller
branches just above a bud or twig.

39. When the larva first begins burrowing upward through
the limb, its presence can be detected by the white powdery dust
expelled from the hole. Later this changes to cylindrical pellets,
light golden or brown in color. New openings through the bark
are made from time to time through which the frass is expelled,
but these holes are sealed with a silken web when not in use. The
pellets collect in clusters below these holes, where they hang sus-
pended by the web, or form small piles on the pavement or ground
below. In this way they betray the presence of the borers, espe-
cially when the larve are nearly grown. If the limb becomes too
small for the rapidly growing larva, the latter leaves its burrow
and enters at another place, usually in a larger limb.

40. ‘The first winter is passed by the larve when about an
inch long, within the burrow, deep in the wood. Up to this time
they have done comparatively little damage to the tree. The
greatest damage is done during the second summer and the spring
following, before the larve change to the pupe. The larve are
now 1/4 to 2% inches long, and are ravenous feeders. They fre-
quently girdle large limbs or excavate large cavities in the wood,

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THE DAVEY INSTITUTE OF TREE SURGERY

weakening the limbs so that they are easily broken by a storm or
fall of their own weight.

41. Control. From what has been said, it is evident that the
control of this pest is a difficult matter, especially upon large
trees. A close inspection of the upper limbs cannot be made to
locate or kill the larve within their burrow, or to remove the af-
fected limbs and destroy them with the contained larve before the
injury is too great.

42. All that can be recommended is to dig out the larve, or
destroy them with a wire or by injecting carbon bisulphide into
their burrows. Infested limbs that fall or are pruned off should
be destroyed before the larve desert their burrows. Repellants
may help to check egg laying, but the whole of the trunk and larger
limbs will have to be protected from May until September to be
successful. The moths can also be collected by trap lights or by
hand and killed. Protecting the native birds that feed upon these
insects is also a powerful means of fighting them.

43. It has been generally observed that healthy, vigorous
trees, while they are not free from attack, are not as badly injured
as the unhealthy ones. Moreover, they outgrow the effect of the
injury much quicker.

2. CARPENTER WORM
Family COSSID/A. Species Prionoxystus robine Peck

44. This moth is a native of this country, but belongs to the
same family as the leopard moth, and has similar habits. The
larve are similar in appearance, but this one grows to be fully
three inches long, and confines its work more to the trunk and the
heart-wood.

45. The carpenter worm was first described by Peck as Cossus
robing, but Newman changed the genus to Xyleutes, and later it
was changed to Prionoxystus,—the name by which it is now known.
It has also received the following specific names: plagiotus Walker,
crepera Grote, reticulatus Lintner, and zabolicus Strecker.

46. Food Plants. It feeds upon black locust, black, red and
white oak, ash, maple, cottonwood, poplar, willow, and chestnut.

47. Symptoms. Large, half-inch galleries in the trunk and
larger limbs, running parallel with the grain and of about the
same size throughout their length, are generally the work of this

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T RE E IN S E € aes

species. Many burrows fre-
quently start from the same
wound in the trunk, the num-
ber increasing from year to
wear,

48. Habits. The large
moths, of a pale gray color,
mottled with black, appear
during June and the early
part of July. They fly only
by night, and hide during the
day upon the rough bark with
the wings folded over the back.
The color of the moth, in this
position, and the color of the
bark, blend in such a way as
to make them hard to find.

49. The female lays 300
or more eggs, placing them in
crevices in the bark or around
wounds made by preceding
generations of the larve. The
young larve feed for a time
upon the inner bark, but

Courtesy New York State Museum, gradually work deeper into
Fig. 2 the heart-wood, several suc-

Work of the carpenter worm in ash. cessive generations feeding

After E. P. Felt. within the same tree. Fitch
states that he found the larvee
feeding only in the sound wood and never in decaying tissue.

50. The larvee when full grown are fully three inches long,
and are of a livid, reddish color, ‘greenish beneath, and witha black,
shining head. The body is somewhat flattened, with scattered,
long, fine hairs. They live within the tree for three or four years.
The pupa is also found within the burrow, and works itself half
way out the exit hole before the skin splits dow n the back to liber-
ate the moth. The cast skin remains in this position after the
moth flies away.

$1. Control. While this is considered to be one of the most
destructive of our native borers, it is more easily controlled than

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THE DAVEY INSTITUTE OF TREE SURGERY

its European cousin. It confines its work more to the trunk and
the larger limbs, and consequently its burrow can be more easily
located, and the larve destroyed with a wire or with carbon bi-
sulphide.

52. Repellents for preventing egg laying would be a more
effective means of fighting this insect, inasmuch as only the trunk
and larger limbs have to be protected instead of the whole tree, as
with the leopard moth. The moths fly only during the month of
June and part of July, so the protection would also be required
for a much shorter time. Where the trees are badly enough in-
jured to require it, the affected heart-wood should be removed and
the cavity filled, as explained in a subsequent lesson.

3. MAPLE SESIAN
Family SESHD/. Species Sesia acerni Clem.

53. This moth is much smaller than the preceding species,
and represents another family of boring lepidopterous larve. It
isa small, wasp-like moth, with transparent wings and black mark-
ings. The head and a tuft on the tip of the abdomen are a bright
red.

54. The red-headed larve of these moths burrow in the newly
forming callus around wounds, thus preventing healing. At times
they cause quite serious injury to both hard and soft maples.
They have the same habit as other boring Lepidoptera of leaving
the cast pupa skin in
the exit hole after the
moth emerges.

COLEOPTERA

55. The greater part
of the insects that bore
into the woody tissues
of plants belong to this
order. Most of them
belong to three fam-
ilies, and are included

7 i Courtesy Illinois State Entomologist.
in the three following Fin. 3

groups: Maple Sesian. After S. A. Forbes.

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S HA DE TREE INS ECTS

The round-headed borers, or those belonging to the
family CERAMBYCID.
The flat-headed borers, or those belonging to the family
BUPRESTID&.
The bark beetles, or those belonging to the family
SCOLYTID#.

ROUND-HEADED BORERS
56. CERAMBYCID. The beetles of this family are called

the “long-horn beetles,” from the long antennz or feelers, which
usually equal or exceed the length of the body. The body is
usually more or less cylindrical, although some species are more
or less flattened.

37. The larve are called “round-headed borers” because they
usually bore into woody plant tissue, and are more or less cylindri-
cal in form, with the segments well marked. ‘The legs are rudi-
mentary or wanting, the thorax enlarged but round, and the
mouth parts strong, well developed, and more or less contracted
within the enlarged thorax. For the most part these larve burrow
into dead or dying wood, but a few of them will attack and fre-
quently kill living trees.

4. MAPLE BORER
Family CERAMBYCID. Species Plagionotus speciosus Say

s8. This is one of the most destructive of the round-headed
borers, and readily attacks trees in apparently good health. It is
a native American, and its work was described as early as 1828.
It has been discussed in the literature under the following names:
Glycobius speciosus Say, clytus speciosus Say, Clytus hayit and
Arhopolus speciosus Say.

59. The sugar maple is the principal food plant attacked, but
the other maples suffer at times.

60. Symptoms. ‘The beetles are sun lovers, so the portion of
the trunk or limbs exposed to the bright sunlight is the most liable
to attack. In the fall, the location of the young larve in the bark
can be detected by a rusty, irregular discoloration of the bark
about the size of a cent, and by the frass, or castings, which have
been expelled from the burrow. These castings are frequently in

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THE DAVEY INSTITUTE OF TREE SURGERY

the form of a spiral attached to the bark,
and an inch or more in length.

61. Later, when the tree attempts to
heal the burrow, the bark is pushed up in
the form of a ridge following the burrow.
The burrows usually run upward and
around the trunk or limb, but may run in
other directions in certain cases. Frequently
they cut off an area of bark, causing it to
die and peel off, especially if two or more
borers are working in the same tree.

62. Habits. The large black, cylindri-
cal beetles, with yellow head and legs and
conspicuous yellow markings on the back,
appear in July and August, and begin lay-
ing eggs in obscure gashes in the bark. On
hatching, the larve burrow into the bark or
just into the cambium, and there pass the
first winter.

63. The following summer they pen-
etrate the cambium and feed until the ap-
proach of the second winter, when they
penetrate deeper into the wood. ‘The
second spring the burrowing is continued
under the bark, but at a more rapid rate.
A short time before pupating they again
enter the hard wood, working inward and
upward, forming a chamber in which to
pupate. The total length of the burrow
may vary from one to three feet. The bur-
row at the last is one-half inch wide and
one-third inch deep.

64. Control. From what has been said,
you can see the dangerous nature of the

Courtesy New York State
Entomologist.

Fig 4.

Sugar maple borers,
natural size. The lower
one a male and the others
females. Note the vari-
ations in the markings.

After J. A. Lintner.

work of this insect, and the difficulty of reaching it after it once
penetrates well into the tree. To attempt to follow the burrow
and kill a nearly full-grown larva would make a serious wound

inthe tree.

65. This can be avoided by the use of repellents during July
and August to prevent egg laying, or by locating and killing the

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» H AD E T R EB E I N S EVC aes

larve during the fall and winter before they reach the cambium.
Old burrows will heal more quickly if cleaned out and properly
dressed.

5. ROUND-HEADED APPLE TREE BORER
Family CERAMBYCID. Species Saperda candida Fabr.

66. This is another of our native borers which is capable of
doing a great amount of damage to many of our shade and orna-
mental trees, as well as to the fruit from which it receives its com-
mon name. In many sections it is so destructive to the apple

Courtesy Connecticut Agr. Exp. Station.

Fig. 5.

Rounded-headed apple tree borer, and its work.
Natural size. After W. E. Britton.

trees that some class it next to the codling moth as being the
most destructive of the insects affecting the apple. Its deeds are
dark and consequently most of its work is done under cover of
darkness, preventing any but the closest observers from becoming

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THE DAVEY INSTITUTE OF TREE SURGERY

acquainted with the conspicuous adult beetle when laying her
eggs upon the bark. Figure 5 is a remarkable photograph of this
beetle upon the trunk of a tree from which it has recently emerg-
ed through one of the holes in the bark. Figure 6 is a cross sec-
tion of the same tree, showing the destruction wrought by a few
of the larve.

67. It was first described by Fabricius in 1787 as Saperda
candida,—the ‘‘white Saperda,” and in 1824 by Say as Saperda

Courtesy Connecticut Agr. Exp. Station.
Fig. 6
Work of the rounded-headed apple tree borer in cross
section. After W. E. Britton.

bivittata or the “‘two-striped Saperda.” It has been extensively
discussed under both of these names.

68. Food Plants. This species has been reported as feeding
upon the following plants: mountain ash, hawthorn, quince, apple,
pear, crab apple, chokeberry and June-berry.

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S HA DE T R EE iN SE € Ts

69. Symptoms. Unless the trees are closely watched, the first
indication of the presence of these borers is the gradual decline or
the death of the tree, or the breaking of the trunk in a storm near
the ground.

70. If the trees are carefully examined each May and Septem-
ber, the borers can be located in the trunk close to the ground. You
can detect their presence by means of the small areas of discolored
or dead bark, or by the sawdust expelled from the burrows.

71. Habits. The adult is a light brown, cylindrical beetle,
with the antenne as long as the body, and with two silvery white
stripes running the full length of the back. It emerges through a
round hole in the bark. In size it is about three-quarters of an
inch long. It flies by night and is seldom seen in the daytime.
The eggs are mostly laid in slits in the bark near the surface of
the ground. Occasionally, however, the eggs are laid farther up
the trunk or upon the larger limbs.

72. The larve on hatching burrow downward through the
bark, expelling orange-colored castings from the opening. For a
time they feed just under the bark. The first winter is passed in
the sap-wood at or below the surface of the soil, in a dormant con-
dition; but the larvz begin feeding again in the spring. The sec-
ond summer the sap-wood is mined at the base of the tree or below
the ground, in many cases being entirely girdled by the borer.

73. ‘The second winter is passed near the surface of the ground,
and in the second spring a burrow is made upward through the
heart-wood, curving outside, and finally ending just under the outer
bark. After plugging the hole with sawdust at both sides, the larva
pupates about an inch back from the bark and emerges as the beetle
in May, June or July, thus feeding for nearly two years within the
tree. Most of these beetles come out in June.

74. Control. Digging out the young larve in October of each
year, when they are’ still in the inner bark, is probably the safest
and surest method of control. The use of the repellent washes de-
scribed in Paragraphs 41-44 of Lesson Eight is also strongly rec-
ommended to prevent egg laying, but the trees must be protected
from May until July, through the whole egg laying period.

75. The trees can also be protected by wrapping the trunk with
wire cloth, paper or other mechanical protectors, to prevent the
beetles from reaching the base of the tree. Vigorous, rapidly grow-

Page 16

THE DAVEY INSTITUTE OF TREE SURGERY

ing trees tend to drown out the larve before they penetrate the
bark, and are consequently less subject to attack.

6. ELM BORER
Family CERAMBYCID. Species Saperda tridentata Olivier

76. This is another native Saperda, and probably does not at-
tack the trees until they are weakened through some other cause or
agency. They become very abundant in certain localities from
time to time, and kill many magnificent elms by undermining the
bark and cutting off the food supply, thus causing the bark to
separate from the wood in large flakes.

77. The elm borer has been known in the literature as Comp-
sidia tridentata, Compsidia tridentata var. dubiosa, and as Saperda
trilineata.

78. Itis generally associated in its destructive work with three
other borers, the reddish elm snout beetle,
Magdalis armicolis Say; the black elm snout
beetle, Magdalis barbita Say, and the Amer-
ican elm borer, Neoclytus erythrocephalus
Fabr. The elm borer is probably the primary
cause of the injury, as it is found in the liv-
ing tissues, while the others are found in the
dead or dying tissues.

79. These borers work just under the
bark, making irregular burrows which, if
abundant, eventually girdle the trunk or
limbs. The work is done so secretly that
frequently their presence is not suspected
until the trees are beyond hope.

80. The life history of the elm borer has
never been carefully worked out, but it is
probably the same as the life history of the
other Saperdas, requiring two or three years
for the larva to mature. The larva is a

typical round-headed borer, a little over an | dadenaal ‘illiias
inch in length when full grown. The beetle Courtesy Iinois State

is of a grayish color, with a reddish margin Fig. 7

tothe thorax and a red stripe-near the outer E4yy borer enlarged,

edge of each wing cover, and three teeth of After S. A. Forbes.

Page 17

S H ADE FREE I N 8S EC tes

the same color extending inward and backward from them. These
teeth may or may not meet on the middle line.

81. Control. Owing to the nature of their work and the diffi-
culty of detecting their presence before serious injury is done, the
elm borer is a difficult pest to control.

82. Cut and burn all badly infected trees or parts of trees
before May to prevent the beetles from emerging. Force the growth

Courtesy Illinois State Entomologist.
Fig. 8.
Elm borer larva. After S. A. Forbes.

of the remaining trees as much as possible. On valuable trees,
remove all dead or badly infested bark to kill the borers under it,
scrape off the outer bark from the rest of the trunk and larger
limbs if infested, and spray it thoroughly with 15% kerosene emul-
sion. If the trees are thoroughly sprayed with repellents from June
to the middle of August, this will tend to prevent egg laying. If
the cambium is exposed it can be protected from drying out by the
composition described above (paragraphs 18-28).

7. LOCUST BORER
Family CERAMBYCID. Species Cyllene robine Forst.

83. This-round headed borer is so destructive to black locust
that it is difficult to grow these trees with any prospect of success
in many localities. It has been described under the following
names: Leptura robine Forster, Leptura picta Drury, Clytus
flexuosus Fabr., Clytus pictus Drury, and Clytus robine Forst.
It has also frequently been confused with the hickory borer.

84. ‘The adult is a beautiful black and yellow beetle, quite
similar to the maple borer. ‘These are also lovers of the bright sun-

Page 18

THE DAVEY INSTITUTE OF TREE SURGERY

light, and can easily be found upon the blossoms of the golden rod
or upon the sunny side of the trunk of the locust. They feed upon
the pollen of the golden rod and upon the juices of other plants.
They will feed freely upon sweetened baits.

85. The eggs are laid upon the bark during the period when
the golden rod is in bloom, the first adults appearing about the
same time as the first golden rod blossoms. ‘The larve on hatch-
ing burrow into the bark, and pass the winter in a small cell in the
inner bark. The next spring they go deeper, burrowing through
the cambium layer and later into the solid wood. The injury is
so severe that the trees are girdled, or the heart-wood is so weak-
ened that the tree is easily broken in a storm. The larva requires
but one season to complete its growth.

86. Control. A number of remedies have been suggested.
One suggestion calls for the destruction of all locust trees; another
the hand picking of the beetles, and a third the destruction of the
golden rod, upon which the beetles feed.

87. The more promising control measures include the use of
repellents from the last part of August to the first part of October
to prevent egg laying, the use of sweet poisoned baits to kill the
beetles before they lay their eggs, and the spraying of the
trunk and larger limbs in the fall with
strong kerosene emulsion to kill the young
larvee, which pass the winter in cells just
under the outer hard bark.

88. In all control measures, you
should not overlook the importance of
reducing the number of beetles by des-
troying all badly affected or worthless
trees during the winter or early spring,
before the larve complete their
growth.

89. The trees can be prevented from
sprouting by peeling the bark from the
trunk during August. If the wood is
valuable, the larve can be prevented
from entering it by removing all the bark

. . - bs Co rtesy x e of. cs)
during the fall or winter. This will also ieee oS a
pill the larve, as they are unable to de- a
velop in the bark alone. Locust borer (female).

Page 19

S HA DE T KR EE INSECTS

go. Severe pruning and the forcing of the growth has caused
affected trees to outgrow the injury from this pest when not too
severe. Many of the larve die from fungous diseases and othe

causes.
8. HICKORY BORER
Family CERAMBYCID. Species Cyllene carye Gahan

gt. This species is very closely related to the locust borer,
and for a long time the two were confused or considered as the
same insect. The locust borer feeds entirely upon the black locust,
but the hickory borer feeds upon hickory, walnut, mulberry,
Osage orange and honey locust, but not on black locust.

g2. It has been discussed in the literature under the follow-
ing names: Leptura picta Drury, Leptura robine Forst., Clytus
Hexuosus Fabr., Clytus pictus Drury, Clytus robine Forst.,
Cyllene robiné Forst., Cyllene pictus Drury, and Cyllene carye
Gahan. The last name has been in use but a short time in the
American literature.

93. The larve work under the bark and in the wood of dead
or dying trees; consequently, it is not of great importance as a
shade tree pest.

94. The control consists in keeping the trees in a healthy con-
dition, or in the use of repellents during the egg laying period
from April through May.

g. LINDEN BORER
Family CERAMBYCID. Species Saperda vestita Say

95. This species is very similar in its habits to the round-
headed apple tree borer, working at the base of the tree and in the
roots, and burrowing under the bark or deep into the wood. Very
little is known about its life history or the length of the larva stage.
Its food is probably restricted to the linden, although this species
has also been reported upon elm, poplar and apple.

96. The beetle is a typical Saperda, black in color, but cov-
ered with a dense olive pubescence. There are usually three spots
on each wing cover where the pubescence is wanting, and the spots
show as black. In some specimens, part or all of these spots may
be wanting. The adults appear the latter part of the summer,
and feed for a time upon the tender bark and leaves, and may
when abundant, cause some injury in this way.

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THE DAVEY INSTITUTE OF TREE SURGERY

97. ‘The control, as far as known, is the same as-for the apple
tree ore é., protecting the trunk and exposed roots from
ttack.
¥ 10. POPLAR BORER

Family CERAMBYCID. Species Saperda calcarata Say

98. This is the largest of our native Saperdas, measuring from
one to one and one-fourth inches long. Together with the broad-
necked Prionus, it makes it next to impossible, in many sections,
to grow the Lombardy poplar. The larva is nearly two inches long,
making a half-inch burrow under the bark and through the heart-
wood. Packard regorts taking eight to ten larve from a section
of a five-inch trunk ten inches long.

99. It causes serious injury to Lombardy poplar, cottonwood,
quaking aspen and willows. It has also been reported from apple.
The adults can be found on the trees during August and Septem-
ber in the northern states.

100. The nature of its work and the lack of a full record of
the habits and life history of the species make it difficult to know
the best methods of control. Digging out the larve, the use of
carbon bisulphide in the burrows and the use of repellents to pre-
vent egg laying, are the only remedies to be suggested. ‘The de-
struction of badly infested trees will also help to reduce the injury,
by reducing the number of beetles.

11. BROAD-NECKED PRIONUS
Family CERAMBYCIDZ. Species Prionus laticollis Drury

101. This is one of the largest of the borers belonging to this
family. The beetles, one to one and one-half inches long, are broad,
black, and have three irregular teeth on either side of the thorax.
The larve are round-headed borers with rudimentary legs, and
when full grown, are fully three inches long. They burrow in the
trunk and roots of Lombardy poplar, balm of Gilead, black oak,
pine, apple and grape vines. Most of their work is underground,
making them difficult to control.

12, OAK TWIG PRUNER
Family CERAMBYCID/. Species Elaphidion villosum Fabr.

] 102. While this species is a typical round-headed borer, it has
f peculiar habit that throws it into a class by itself, as indicated by

Page 21

S HA DE T R EE IN 8S E € Fess

its name. The larve are provided with rudimentary legs. Its
peculiar habits and the nature of its injury were first described by
Peck in 1819, although Fabricius had described the adult at a
still earlier date.

103. The species has been discussed under the following names:
Stenocarnus villosus Fabr., Stenocarnus putator Peck, Elaphidion
parellelum Newman, Elaphidion putator Peck, and Elaphidion
villosum Fabr.

104. The dark brown, slender, cylindrical beetle, covered
with a mottled grayish pubescence, appears in early summer and
usually deposits the eggs in a tender branch. The larva first feeds
by burrowing the tender branch toward the main limb. On reach-
ing the latter, it tunnels through the wood or pith, and when about
half grown, cuts the twig partially off at the lower end of the bur-
row. This it does by eating away the wood from the inside, but leav-
ing the bark and enough wood
to keep the twig from breaking
until dry. The larva retreats
up the limb, and plugs the hole
below it with sawdust and
wood fiber. The first strong
wind breaks off the twig,
carrying the voluntary pris-
oner to the ground with it.
Here the larva lives, feeding
upon the dead wood until the
next summer, when it pupates
and the mature beetle emerges.

105. In some seasons this
pest is so abundant that the
fallen twigs can be_ picked
from under the trees by the
wagon load. If these are
gathered and burned while the
larve are still within, the
number of beetles present

Ciminy Uncle Sinks Bnkenalogist, the next season will be greatly
Fig. 10. reduced. This is the only

Gale sacar anes tae Salaeed: method of control that can bq
After S. A. Forbes. suggested, with the addition

Page 22

THE DAVEY INSTITUTE OF TREE SURGERY

of removing any dead twigs that may be still hanging to the
trees.
106. The food plants include oak, hickory, chestnut, beech,
Dsaice. birch, firs, locust, redbud, sumach, orange, Osage orange,
apple, plum, quince, peach, grape and bittersweet.

13. TWIG GIRDLER
Family CERAMBYCID. Species Oneiders cingulatus Say

107. The adult of this peculiar round-headed borer appears in
July and August. It is similar in its habits to the twig pruner, in
so far that it cuts the twigs from the tree upon which the larva is
to feed. It differs from this species, however, in that the beetle
cuts the twig from the tree instead of the larva. This is done by
cutting a U-shaped groove around the twig, leaving nothing but a
small portion of the heart-wood. When this dries it is easily broken
by the wind. The eggs are laid in a crescent-shaped cut in the
bark, above the point where the twig is girdled. These may hatch
before or after the twig falls. The larva feeds within these twigs
and emerges as the adult beetle the following summer.

108. ‘The simplest and most effective control is to collect and
destroy these twigs as fast as they fall.

tog. They attack hickory, pecan, persimmon, elm, linden, oak,
apple, pear, quince, peach, orange, and rose bushes.

14. HEART-WOOD BORER
Family SPONDYLIDE. Species Parandra brunne Fabr.

110. While the larva of this species closely resembles the
round-headed borers and has similar habits, the adult beetles are
very different. These are about three-quarters of an inch long and
one-third as wide. In color they are a chestnut brown. They are
much flattened, and in general appearance resemble the common
pinching bug, but with smaller mandibles or pincers.

111. ‘The larvz live in the heart-wood of different trees, gain-
ing entrance through a wound and then honeycombing the heart-
wood, causing rapid decay. This has not been generally consid-
ered to be a pest of shade and fruit trees until recently, owing to

he fact that its work has been confused with the work of the round-
eaded apple tree borers It has been found to cause serious dam-

Page 28

S HA DE TY EK.E E INS £ CT &

age to telephone poles, and consequently has received the name o
’ the chestnut telephone pole borer. C. A. Hart also reports it a:
doing serious damage to apple, maple and other trees, includin;
conifers, burrowing into the sound wood and hastening decay.

112. Control. So little is known in regard to the habits o:
this species that control measures have not been worked out
From what is known it will probably cause little trouble if wound:
are properly protected against decay and the cavities are properly
cleaned out and filled.

FLAT-HEADED BORERS
113. BUPRESTIDZ. A large proportion of the beetles be.

longing to this family are bronzed or have a metallic luster, and other:
are marked with gaudy red or yellow bands or spots. The beetle:
are elongate, usually stout, but sometimes cylindrical, and have <
broad thorax and elytra tapering back from the shoulders. The
prothorax is closely united with the mesothorax and is usually
somewhat flattened. Most of them are so characteristic in ap-
pearance that they are easily recognized.

114. ‘The larve are also very characteristic, with their slende1
abdomen, the segments well defined, and their large flattenec
thorax with the small head and strong mouth parts partly con-
tracted within it. When at rest, the abdomen is usually curvec
back upon itself in the form of a U. Most of these larve feed upor
dead or dying trees, burrowing under the bark or through the wood.
making rather broad but shallow galleries or chambers. However.
some of them feed upon living tissue, and in some cases seem tc
attack trees in perfect health. The common names of “‘flat-
headed”’ or ““hammer-headed”’ borers came from the slender ab-
domen and greatly enlarged and flattened thorax.

15. FLAT-HEADED APPLE TREE BORER
Family BUPRESTID. Species Chrysobothris femorata Fabr.

115. ‘This bronze-colored beetle, about one-half inch long, car
frequently be seen on the sunny side “of the trunk of fruit and shade
trees during the latter part of May to July. It is a native species
widely distributed throughout the United States and Canada, anc
even extends its range into Mexico. When first described it wa:
placed in the genus Buprestis, but later transferred to the genu:

Page 24

THE DAVEY INSTITUTE OF TREE SURGERY

Chrysobothris. Eight or more varieties of this species have
been described. Among these are alabame Gory, fastidiosa
Gory, lesueurt Gory, misella obscura Lec., 4-impressa Gory,
semisculpta Lec. and soror.

116. The beetles deposit their eggs during June and July,
mostly upon the bark exposed to the sun, and at times it is a ques-
tion whether the primary cause of the injury is due to the borers
or to sun-scald or winter injury. However, there is no doubt but
that healthy trees are less liable to attack than diseased trees.

117. The food plants include oak, soft maple, mountain ash,
box elder, hickory, chestnut, sycamore, horse chestnut, beech, wil-
low, cultivated redbud, apple, pear, peach, plum, cherry, and cur-
rant.

118. Control. In orchards the best preventatives are clean
culture and care, tending to produce vigorous growth, together
with proper pruning to prevent exposing the trunk or large limbs
to sun-scald. The trees should also be carefully inspected in fall
and spring to kill any borers that may be found in trunk or large
limbs. The use of repellents has also given good results. The
larva do not burrow deep into the wood, so can be more easily
located and killed than the larve of the round-headed borer.

16. BRONZE BIRCH BORER
Family BUPRESTID. Species Agrilus anxius Gory

119. This flat-headed borer has killed many of the magnifi-
cent birches in some of our northern cities, but has not been found
to be injurious to trees under forest conditions. This is probably
due to the effect of the birds and other natural enemies. In the
cities, when a tree becomes infested, it seldom lasts more than two
to three years. The species was first described in 1841. It has ap-
peared in the literature under the names of Agrilus anxius Gory,
Agrilus gravis Lec., and Agrilus torpidus Lec.

120. The first indication of the destructive work of this borer
is usually seen in the dying of some of the top branches. These
are usually the first to become infested, and consequently the first
to be injured. When the trees reach this stage, no remedy is
known that will save them. The only thing to be suggested in

po cases is the complete destruction of the affected trees, includ-
ing all the branches down to one-quarter inch, before May Ist, to

Page 26

S HA DE T REE IN 8S £ CTs

prevent the beetles from emerging and spreading to healthy
trees.

121. The small, bronze green or violet beetles are about one-
half inch long, with parallel sides, but conspicuously tapering
wing covers with a blunt tip and a notch where they meet. They
emerge through peculiar bean-shaped holes in the bark during May
and June. The eggs are laid during these months in cracks in the
bark.

122. The larve on hatching penetrate the bark with zig-zag
burrows, and work just under the bark, making tortuous burrows
that frequently intersect, and soon girdle the tree if abundant.
When the larve are full grown, the burrows are about one-eighth
inch in diameter. Professor Slingerland has demonstrated that
from June Ist to October Ist a larva is capable of making a burrow
over five feet long.

123. When full grown the larva is about three-quarters of an
inch long, with the characteristic of the flat-headed borer, but
with a peculiar brown, horny, forcepslike appendage at the caudal
end of the body, with two teeth
upon the inner side of each of the
two prongs. This pest seems to
prefer the European white birch,
but will also attack and kill some of our
native species, including the black and
vellow birch. It has been known to
also attack the paper, or canoe birch.

125. As stated above, when a tree
begins to die at the top the only rem-
edy is to cut and burn the tree before the
beetles emerge and spread to other trees.
If all badly infested trees are promptly
destroyed, the number of beetles that
emerge can probably be reduced to the
point where their natural enemies will
control them. The secrecy of their
Courtesy Illinois State Entomologist. attack, and the habit of starting upon

Fis: ii. the upper limbs, puts this pest practi-
Bvdhoe iiss Bese: cally beyond the reach of the oo
After S. A. Forbes. insecticides.

Page 26

THE DAVEY INSTITUTE OF TREE SURGERY

17. TWO-LINED
CHESINUT BORER

bFamily BUPRESTIDA.
Species Agrilus bilineatus
Weber

126. This borer is similar
to the bronze birch borer,
but is only three-eighths
inch long and makes a
smaller burrow. When full
grown, the burrow is but
one-quarter inch in dia-
meter, and is confined
largely to the bark and Fig. 12.
cambium layer. In some Exit holes of the bronze birch borer in bark
cases the larva feeds en- of white birch. After Slingerland.
tirely within the bark and
does not enter the wood.

The larva closely resembles the bronze birch borer, but is only
three-quarters inch long when full grown. Its work is confined to
the chestnut, oak, and beech. Some writers think that it will attack
healthy trees, but in some cases the chestnuts will be badly injured
or killed, while the oaks near them remain uninjured. The
evidence strongly indicates that injured trees are the ones attacked.

127. The larve usually pupate in the bark, and the beetles
emerge in May and early June. The latter are long and slender,
about three-eighths inch long and one-third as broad, and of a
dark brown to black color, with a greenish tinge. The sides of the
thorax and wing covers are a light golden yellow, with a strip of
the same color running the full length of each wing cover.

128. The size of the burrows and the habit of working in all
parts of the tree, makes this a difficult pest to control. In most
cases they will have to be left to the control of their natural ene-
mies, after destroying or barking the badly infested trees, in this
way destroying the larve before the beetles emerge in May and
June. By removing the bark and burning it, the insects can be
killed and the wood saved for other purposes. For valuable trees,
he repellents can be used during May, June, and the first part of
Bay to prevent egg laying. The trunk and large limbs can also

Courtesy Cornell Agricultural Experiment Station.

Page 27

S HA DE 1 B&B EE LLNS EC Ts

be sprayed with penetrating contact insecticides to kill the larve
when small. The larve are too small to dig out or kill with a wire.

BARK BEETLES
129. SCOLYTIDA. The beetles belonging to this family are

commonly known as the bark beetles, bark borers, or ambrosia beetles.
They are very small, cylindrical, black or brown, and seldom much
over one-fifth inch in length. The adult female of the bark beetles
burrows through the bark and makes a gallery in the cambium
layer, in which she lays her eggs. The eggs hatch, and the legless
grubs mine through the cambium layer in such a peculiar and char-
acteristic manner that it is easier to tell many of the species by the
burrow than by the adult beetles. The ambrosia beetles burrow
more deeply into the wood and cultivate ambrosia, or a fungous
growth, within the galleries, upon which they feed and upon which
to feed the young.

18 HICKORY BARK BORER
Family SCOLYTID. Species Eccoptogaster quadrispinosus Say

130. ‘The hickories in many sections have been killed by the
hundreds by this pest. It works so secretly that frequently the
trees are dying before the presence of the pest is suspected. The
outbreaks that occur from time to time probably follow injury to
the trees by adverse weather conditions or injury from leaf eating
or other insects. This species has been considered in the literature
mostly under the name Scolytus quadrispinosus Say. Riley de-
scribed the female as Scolytus carye, but this name was dropped
on finding that the difference was due to the difference in sex. It
has recently been changed to the genus Eccoptogaster.

131. Habits. ‘The dark brown or black beetles, about one-
fifth inch long, emerge during the last of June and July through
holes in the bark about the size of number eight shot. They feed
for a time upon the young nuts, at the base of the leaves, or burrow
into the young twigs, causing them to wilt, die or fall. The wilting
or falling of these leaves and twigs is usually the first signs of their
presence, and should be the warning to watch for more serious in-
jury later.

132. During August, the females begin to burrow into th
bark, usually starting their galleries in a crack or under a bark

Page 28

THE DAVEY INSTITUTE OF TREE SURGERY

scale, making vertical brood chambers, just under the bark, about
one and one-half inches long and one-eighth inch in diameter.
». In small pits on either side of this brood chamber, twenty to
fty eggs are laid, which soon hatch into small legless grubs which
begin burrowing through the cambium at right angles to the parent
chamber. The end burrows gradually diverge from the others,
spreading out fan-shaped, until the end ones finally run nearly
parellel to the brood chambers. The grubs grow rapidly and con-
tinue to extend their individual galleries until the latter are two
to three inches long and the grubs are about one-quarter inch long.

133. The winter is passed within the burrows as nearly full
grown larve. In the spring the work is continued, and their
growth completed the latter part of May, when the larve change to
pupe. The adult beetles emerge about a month later through
small round holes in the bark. Thus it will be seen that each
colony will thoroughly undermine a portion of the bark from four
to six inches square.

134. The brood chambers are placed with such regularity
over the trunk and larger limbs that it does not require a very
large number of them to completely girdle a tree. In a section
where serious damage is being done, several hundred of these colo-
nies can be found in a single tree of moderate size.

135. Control. From what has been said it is evident that this
pest is a difficult one to control. In an outbreak covering a large
area, or upon a large estate, the principal method of control con-
sists in making a thorough inspection of the entire infested area
in the early fall, and marking all badly infested trees and trees that
have died since June of the current year. During the winter and
spring all these trees are destroyed, or the bark removed and
burned before May to kill the larve before they can emerge and
spread to the healthy trees. If this is carefully done throughout
the area, it will so reduce the number of borers that the natural
means of control will prevent further serious injury. With small
estates the greatest difficulty with this method is to secure the nec-
essary cooperation among the different owners, so they will all
carry out their part of the program.

136. For small estates or valuable trees the following cam-
paign is the one promising the best results: ;

> 137. First—Remove and destroy all badly infested trees or
parts of trees as before.

Page 29

S HA DE i RE E INSECTS

138. Second—Force the growth in the remaining trees by
every means available.

139. Third—Use repellants on the trunk and larger limba
from the last of June to the middle of August, to prevent the fe-
males from entering the bark.

140. Fourth—Keep close watch during July and August for
the injury of the beetles, as indicated by the falling, wilting or
dying of the leaves or tender shoots.

141. Fifth—If these signs of the presence of the beetles are
found, be on the watch for the first signs of the work of the females
in entering the bark preparatory to egg laying.

142. Sixth—lf but a few trees are involved, locate the entrance
to the brood chambers, usually in cracks or under bark scales, by
the fine sawdust found in the crack or upon the bark. With a
small oil can squirt a small amount of gasoline into each of these
brood chambers. Mr. Bird, of New York, reports treating in this
way a 40-foot tree infested with 200 to 300 brood galleries in
three hours’ time and using but a quart of gasoline.

143. Seventh—Spray the trunk and larger limbs thoroughly
with 25% kerosene emulsion, using an excess of whale-oil soap.
To this add “Black Leaf 40” at the rate of one part of the “Black
Leaf 40” to 400 parts of the diluted emulsion. Care must be
taken not to get much of this upon the foliage, on account of the
danger of injuring it or causing it to fall. This application is
made when the females are making the brood chambers, and be-
fore the larve penetrate tco far from this chamber.

144. The following solution is reported as very promising by
Dr. Felt for use in the same way: 1 gallon soft soap, 1 gallon
hot water, I pint crude carbolic acid. Mix thoroughly and allow
to stand over night, when it is ready for use after being diluted
with eight gallons of cold soft water.

19. ELM BARK BEETLE
Family SCOLYTID. Species Eccoptogaster multistriata Marsh

145. his is an imported species, very similar to the hickory
bark borer, and promises to cause as serious injury to the elms as
the latter species does to the hickories. It has been reported frong
eastern Massachusetts.

Page 80

THE DAVEY INSTITUTE OF TREE SURGERY

146. The control is the same as for the other species, with the
first consideration being given to keeping the trees in a healthy
condition.

> 20. MOTTLED WILLOW BORER
Family CURCULIONID. Species Cryptorhynchus lapathi Linn.

147. This is an introduced species, belonging to a family con-
taining a number of notoriously i injurious species, but only a few
borers. This species was first reported in this country in 1887,
near New York, but has since spread throughout the Northeastern
States and westward across the Mississippi. It is very destructive
to nursery stock, working on willows, balm of Gilead, cottonwood,
and several of the poplars.

148. It can be controlled to some extent by spraying with
strong arsenate of lead, to kill the beetles when feeding upon the

bark.
HYMENOPTERA

149. This order contains comparatively few wood borers of
importance. Among the eating insects it is more important.

21. PIGEON TREMEX
Family SIRICIDA. Species Tremex columbia Linn

150. This is one of the larger of the Hymenoptera, and is
preyed upon by one of the largest of the parasitic species of the
same order. In the early literature it was known under the name
Sirex columbia Linn.

151. The adult is a saw fly with four clear wings, with a
spread of about two and one-quarter inches. The black and yellow
cylindrical body is provided at the end with a horn or ovipositor
about three-eighths inch long. The female can frequently be
seen in the latter part of the summer upon dead or injured maple,
elm, oak, sycamore or other trees with its ovipositor, or “saw,”
thrust into the wood. The infested trees are frequently full of
round holes about the size of a lead pencil. In laying the eggs the
female frequently gets the ovipositor so tightly wedged into the
wood that she cannot get it out. Dead specimens can frequently
be found in this position.

152. On the same trees can frequently be seen a large, long-
Pisce, dangerous looking four-winged fly, with a long ovipositor

Page 31

S HA DE F EEE INS ECTS

about three inches long. This is the lunate long-sting, Thalessa
lunator Fabr., or the largest of our native ichneumon flies. The
larva is parasitic upon the larve of the borer under consideration,
and prevents them from becoming sufficiently injurious to required
special treatment.

153. This borer is usually found in dead wood, and its work
is stopped when this is properly removed and the cavity filled.

22. BLACK CARPENTER ANT
Family FORMICID. Species Camponotus herculaneus Linn.

154. he large black ants frequently found in hollow or decay-
ing trees generally belong to this species. It is usually found in
decaying trees, but after it once gains an entrance to the heart-
wood of a number of kinds of trees, it can do extensive damage
by burrowing through the heart-wood, in which it makes its nest.

155. It is hard to check their work, except by digging out the
affected wood and destroying the nest, or by fumigating the cavity
with hydrocyanic acid gas or carbon bisulphide. If you are sure
that the cavity is such that the fire can be controlled and prevented
from spreading farther than desired, the same results can be secured
by burning out the cavity. This, however, is a dangerous practice.

LESSONS 10-11
SHADE TREE INSECTS

PARTS 1-2

HOST LIST

In the following host list the trees are given in alphabetical
order according to their common names.

The insects affecting each tree are indicated by their respec-
tive members as given in Lessons 10 and 11.

Apple—1, 5, 9, 10, 11, 12, 18, 14, 15, 25, 26, 27, 28, 29, 30, 31,
32, 33, 35, 36, 44, 48, 58, 61, 63, 64, 67.

Apricot—33, 68.

Ash—2, 25, 26, 27, 28, 32, 67, 68.

Arbor vitae—33.

Beech—1, 12, 17, 25, 28, 31, 32, 35, 44, 68.

Birch—1, 12, 16, 25, 27, 28, 31, 34, 44, 47, 63, 68.

Basswood—See linden.

Box elder—15, 25, 27, 29, 32, 36, 58.

Balm of Gilead—11, 20, 25, 31.

Catalpa—25, 63.

Cherries—15, 25, 26, 27, 28, 30, 32, 48, 63, 68.

Cottonwood—2, 10, 24, 61, 63, 64.

Chestnut—2, 12, 15, 17, 29, 31, 63, 67, 68.

Crab-apple—5, 25, 26, 44, 48.

Dogwood—1, 68, 68.

Elm—1, 6, 9, 13, 19, 21, 23, 25, 28, 29, 30, 31, 32, 33, 34, 41, 43,
45, 50, 55, 57, 68, 65, 68.
American—23, 25, 28, 44, 50, 53, 54, 58,
English—23, 25.
Scotch—23, 25.

Fir—25, 27.

Ginkgo—25.

Gum—1, 25, 28.

Hackberry—1, 30, 58.

Hawthorn—5, 35, 44, 64.

Hemlock—25, 33.

Hickory—1, 8, 12, 13, 15, 18, 27, 28, 29, 31, 32, 36, 52, 68.
Shag-bark—25.

Horse chestnut—1, 25, 27, 28, 31.

Juneberry—65, 68.

Juniper—25.

Kentucky coffee tree—25.

Larch—25, 27, 33, 42, 46.

Linden—1, 9, 13, 25, 26, 28, 30, 31, 33, 58, 63, 64, 68.
European—25, 27.

Locust—2, 7, 12, 25, 28, 33, 44, 68.
Honey—8, 25, 27, 35, 58, 64.

Magnolia—28, 62, 68.

ae Ts 2, 3, 14, 21, 25, 29, 31, 33, 49, 58, 59, 60, 61, 63, 64,

Sugar—4, 25, 26, 28, 64.
Soft or red—15, 25, 26, 27, 36, 58, 61, 68.
Norway—27, 64.
Mountain ash—1, 5, 15, 25, 28, 63.
Mulberry—1, 8.

Oak—1, 12, 13, 15, 17, 21, 22, 25, 27, 28, 29, 32, 33, 35, 37, 44

67, 68.

Black—11, 25, 68.

Red—2, 25, 68.

Scarlet—2, 25, 68.

White—2, 25, 68.
Ohio buckeye—1.
Osage orange—33, 63, 68.
Peach—12, 138, 15, 25, 26, 61, 63, 68.

Pear—1, 5, 18, 15, 25, 26, 27, 29, 32, 33, 36, 48, 58, 61, 63, 64.

Pecan—13, 35, 63.
Plum—12, 15, 25, 26, 27, 28, 30, 32, 33, 48, 61, 63, 64, 68.
Pine—11, 14, 25, 39, 56, 66, 68.
Poplar—2, 9, 20, 25, 28, 31, 33, 34, 36, 39, 41, 63, 64, 67, 68.
Carolina—See cottonwood.
Lombardy—10, 11, 25, 63.
Large-toothed aspen—10, 25, 68.
Quince—5, 12, 13, 26, 27, 33, 61, 63, 64.
Spruce—12, 25, 27, 33, 38, 51, 68.
Sumach—12, 25, 63, 68.
Sycamore—21, 25, 27, 32, 58.
Tulip tree—1, 25, 62, 68.
Walnut—1, 8, 28, 67.
Black—26, 27, 63.
Butternut—27.

Willow—2, 10, 20, 24, 25, 26, 27, 28, 31, 32, 34, 35, 39, 41, 63, 64.

68.
Yellow wood—25.

?

Lesson 10

BIBLIOGRAPHY
Borers.

The references in the following bibliography are selected as
the best ones and those most easily secured. It is not complete but
will helps you to know the different insects. A complete biblio-
graphy would be confusing and require too much space as the
references for some of the species would be greater than the total
references given below.

The two most comprehensive works on this important subject
are Packard’s Fifth Rept., U. S. Entomological Commission, and
Memoir 8, New York State Museum of Natural History, in two
volumes, by E. P. Felt. These are both excellent works and you
should have them. They are getting out of date in some cases in
regard to means of control but they are the best we have at the
present time, treating of the same number of shade tree insects.
Packard’s Report is out of print and is hard to get. It is, however,
the most comprehensive work treating of American forest and
shade tree insects and contains liberal quotations from many of
the early writings which are also out of print.

Send for as many of these references as possible and use them
when studying Lesson 10. Some of them also contain good des-
criptions of other species to be considered in subsequent lessons.

1. LEOPARD MOTH.

. 1894—Southwick, E. B., Insect Life, Vol. 7, pp. 138-140.
. 1897—Webster, F. M., Bul. 77, Ohio Agr. Exp. Sta., pp. 48-50,
fig. 10.

3. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 75-79,
pl. 4, figs. 1-11. Albany, N. Y. 2 vols. $4.00.

4, 1909-——Britton, W. E., 9th Rept., Conn. State Ent. ; Pt. 4, Rept.
Agr. Exp. Sta. for 1909-1910.

5..1909-—-Howard & Chittenden, Cir. 109, U. S. Bur. Ent., pp. 1-8,

figs. 1-2.

Ne

6. 1911—Britton, W. E., Bul. 169, Conn. Agr. Exp. Sta., pp. 3-24.,

pls. 1-8, figs. 1-6.
2. CARPENTER WORM.

7. 1890—Packard, A. S., Fifth Rept., U. S. Ent. Com., pp. 53-58,

fig. 14.

8. 1900—Doten, S. B., Bul. 49, Nev. Agr. Exp. Sta., 7 illus.
9. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, p. 79.

10.

ti.

12.

14.

25.

1906—Cotton, E. C., Bul. 7, Ohio State Dept. Agr., Div. Nur.
& Orch. Inspection, pp. 12-14, Bibl.

3. MAPLE SESIAN.

1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 56-58,
pl. 4, fig. 12-18.

1911—Forbes, S. A., Bul. 151, Ill. Agr. Exp. Sta., pp. 497-498,
figs. 37-38.

4, MAPLE BORER.

. 1890—Packard, A. S., Fifth Rept., U. S. Ent. Com., pp. 374-

379, figs. 137-140.
1895—Weed, C. M., Bul. 33, N. H. Agr. Exp. Sta., pp. 7-9, figs.
8-4,

. 1897—Lintner, J. A., 12th Rept. Ins. N. Y., pp. 237-242, pl. 7,

fig. 1, Bibl. 1824-1897.

. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, p. 51,

5. ROUND-HEADED APPLE TREE BORER.

. 1890—Packard, A. 8., Fifth Rept., U. S. Ent. Com., p. 539.
. 1902—Banks, N., Bul. 34n. s., U.S. Div. Ent., pp. 39-40, fig. 36.
. 1904—Feit, E. P. & Joutel, L. H., Monograph of the Genus Sa-

perda, Bul. 74, N. Y. State Mus. Nat. Hist., pp. 28-39, pl. 1,
8-10, Bibl. to 1902.

0. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Voi. 1, pp. 84-86.
. 1907—Britton, W. E., 7th Rept., Conn. State Ent.; pt. 5, Rept.,

Conn. Agr. Exp. Sta. for 1907, pp. 333-334, pl. 16.

. 1907——Chittenden, F. H., Cir. 32, 3rd Revised, U. S. Bur. Ent.,

pp. 1-7, fig. 1.

. 1908—Garman, H., Bul 133, Ky. Agr. Exp. Sta., p. 49.
. 1912—Sanderson, E. D., Insect Pests of Farm, Garden & Or-

chard, pp. 588-591, figs. 444-445. John Wiley & Sons, New
York. $3.00.

6. ELM BORER.

1890—-Packard, A. S., Fifth Rept., U. S. Ent. Com., pp. 224-
226.

26.
27.

1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. I, p. 67.

1912—Forbes, S. A., Bul. 154, Ill. Agr. Exp. Sta., pp. 13-15, fig.
12.

7. LOCUST BORER.

28. 1890—Packard, A. S., Fifth Report, U. S. Ent. Com., pp.
3855-358.

29.

Ww
Oo

wo
jaarg

ww ow 0
orm Co lx.

wo
oO

37.

AT.

1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 93-97
pl. 5, fig. 3.

’

. 1906—Cotton, E. C., Bul. 7, Ohio State Dept. Agr., Div. Nur.

& Orch. Inspection, pp. 8-12, figs. 1-5.

. 1906—Hopkins, A. D., Bul. 58, U. S. Bur. Ent., pt. 1, pp. 1-6,

pl. 1, figs. 1-6.

2. 1907—Hopkins, A. D., Bul. 58, U. S. Bur. Ent., pt. 8, pp. 31-40.
. 1907—Hopkins, A. D., Cir. 83, U. S. Bur. Ent., pp. 1-8, figs. 1-4.
. 1907—Hopkins, A. D., Yearbook, U. S. Dept. Agr., p. 164.

- 1908—Washburn, F. L., Bul. 112, Minn. Agr. Exp. Sta., pp.

169-171, figs. 39-41.

. 1910—Webb, J. L., Yearbook, U. S. Dept. Agr., pp. 347-349, fig.

22.
8. HICKORY BORER.

1910—Webb, J. L., Yearbook, U.S. Dept. Agr.. pp. 349-350.
9. LINDEN BORER.

. 1890—Packard, A. S., Fifth Rept., U. S. Ent. Com., p. 474, fig.

171.

. 1900—Webster, F. M., Bul. 26 n. s., U. S. Bur. Ent., p. 89.
. 1904Felt & Joutel, Bul. 74, N. Y. State Mus. Nat. Hist., pp.

54-58, pl. 5 figs. 1, 5, Bibl.

. 1905.—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 91-

92, pl. 6 figs. B. C., 7-10.
1909—Levison, Jour, Econ. Ent., Vol. 2, pp. 363-364.

10. POPLAR BORER.

. 1890—Packard, A. S., Fifth Rept., U. 8. Ent. Com., p. 426.
4, 1904—Felt & Joutel, Bul. 74, N. Y. State Mus. Nat. Hist., pp.

39-44, pl. 2 fig. 1.

. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 98-

100, pl. 6 figs. 1-6, 26.

. 1912—Gee, Wilson P., Jour. Econ. Ent., Vol. 5, pp. 336-387, pl.

8.
11. BROAD-NECKED PRIONUS.

1890—Packard, A. S., Fifth Rept., U.S. Ent. Com., p. 437.

48.

49.

50.

57.

58.

59.
60.

61.

62.

63.

64.

65.

66.

67,
68.

1882—Saunders, Wm., Insects Injurious to Fruits, pp. 227-228,
fig. 232. J. B. Lippincott Co., Philadelphia, $2.00.

1906—Felt, E. P., Memoir 8, N. Y. State Mus, Vol. 2, pp. 486-
487, .

12. GCAK TWIG PRUNER.

1882—Saunders, Wm., Insect Injurious to Fruits, pp. 31-33,
figs. 17-20. J. B. Lippincott Co., Philadelphia, $2.00.

. 1890—Packard, A. 5., Fifth Rept., U.S. Ent. Com., pp. 83-

90, figs. 31-32.

. 1893—Chittenden, F. H., Bul. 18 n. s., US. Div. Ent., pp. 35-

AO, fig. 11.

. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 59-

61, pl. 2 figs. 7-9.

. 1906—Cotton, E. C., Bul. 7, Ohio State Dept. Agr., Div. Nur.

& Orch. Inspection, p 46.

5. 1910—Chittenden, F. H., Cir. 130, U.S. Bur. Ent., pp. 1-7, fig. 1.
6. 1911—Forbes, S. A., 26th Rept., I. State Ent., pp. 50-52, figs.

56-57.
1911—-Forbes, S. A., Bul. 151, Tl. Agr. Exp. Sta., pp. 512-515,
figs. 56-57.

13. TWIG GIRDLER.

1890—Packard, A. 8., Fifth Rept., U. S. Ent. Com., pp. 288-
290.

1895—Scheffer, T. H., Insect Life, Vol. 7, pp. 345-347.
1898—Parrott, P. J., Bull. 77, Kan. Agr. Exp. Sta., pp. 56-62,
figs. 29-82.

1905.—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 271-
274, pl. 9 figs. 6-12.

14. HEART-WOOD BORER.

1910—Snyder, T. E., Bul. 94, pt. 1, U. S. Bur. Ent., pp. 1-12,
pls. 1-2, figs 1-3.
1911—-Hart, C. A., 26th Rept., Ill. State Ent., pp. 68-78, figs. 1-5.

15. FLAT-HEADED APPLE TREE BORER.

1890—Packard, A. S., Fifth Rept., U. S. Ent. Com., pp. 64-69,
figs. 16-18.

1895—Lintner, J. A., 10th Rept. Ins. N. Y.; 48th Rept. N. Y.
State Mus. Nat. Hist., p. 488.

1897—Lintner, J. A., 12th Rept. Ins. N. Y.; 50th Rept., N. Y.
State Mus. Nat. Hist., p. 356.

1897—Hillman, F. H., Bul. 86, Nevada Agr. Exp. Sta., pp. 2-4.
1898—Stedman, J. M., Bul. 44, Mo. Agr. Exp. Sta., pp. 16-19.

_ 1898—Faville & Parrott, Bul. 77, Kan. Agr. Exp. Sta., pp. 47-

49, figs. 21-22.

| 1899-—-Harvey & Munson, Bul. 56, Maine Agr. Exp. Sta., pp.

109-110, pl. 2, fig. 2.

. 1900—Lugger, Otto, Bul. 66, Minn. Agr. Exp. Sta., pp. 187-

141, figs. 63-64.
1904—Cooley, R. A., Bul. 51, Mont. Agr. Exp. Sta., pp. 224-227,
fig. 9, pl. 3 figs. 7-8.

. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 86-87.

1907—Chittenden, F. H., Cir. 32, 3rd revised, U. S. Bur. Ent.,
pp. 8-11, fig. 3.
1908—Garman, H., Bul. 183, Ky. Agr. Exp. Sta., pp. 48-49.

76. 1912—O’Kane, W. C., Injurious Insects, p. 2387, figs. 805-306.

77.

89.

90.

Macmillan Co., New York. $2.00.

1912—-Sanderson, E. D., Insect Pests of Farm, Garden and
Orchard, pp. 591-592, fig. 446. John Wiley & Sons, New
York. $38.00.

16. BRONZE BIRCH BORER.

. 1898—-Chittenden, F. H., Bul. 18 n. s., U. S. Bur. Ent., pp. 44-

51, figs. 15-17.

. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 284-

287, fig. 49.

. 1906—Slingerland, M. V., Bul. 234, N. Y. Cornell Agr. Exp. Sta.
1. 1911—Forbes, 8S. A., Bul. 151, Tl. Agr. Exp. Sta., pp. 515-517.
. 1911—¥orbes, S. A., 26th Rept., Ill. State Ent., pp. 53-55, figs.

58-59.
i7. TWO-LINED CHESTNUT BORER.

. 1897—Chittenden F, H., Bul. 7 n. s., U. S. Div. Ent., pp. 67-72,

fig. 42.
1897—Chittenden, F. H., Cir. 24, U. S. Div. Ent., pp. 1-8, fig. 1.

. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 280-

283, fig. 48.

. 1909—Chittenden, F. H., Cir 24, Revised, U. S. Div. Ent.
. 1911—Felt, E. P., 27th Rept., N. Y. State Ent., pp. 118-114, fig.

D.
18. HICKORY BARK-BORER.

. 1890—Packard, A. S., Fifth Rept., U. S. Ent. Com., pp. 294-

295, fig. 118.

1896—Johnson, C. W., Rept. Penn. Dept. Agr. for 1896, pp.
360-361.

1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 275-
279, pl. 39 fig. 4, figs. 46-47.

91.
92.

108.

109.

110.

111.

1910—Felt, E. P., 25th Rept., N. Y. State Ent., pp. 103-104.
1913—Felt, E. P., 28th Rept., N. Y. State Ent., pp. 63-69, figs.
8-9.

19. ELM BARK BEETLE.

8. 1910—-Chapman, J. W., Psyche, Vol. 17, pp. 63-68, pl. 2.
. 1911—Chapman, J. W., The leopard moth and other insects

injurious to shade trees in the vicinity of Boston, Mass., Bus-
sey Institute, Harvard University, Cambridge, Mass., pt. 2.

. 1912—Burgess, A. F.—Jour. Econ. Ent., Vol. 5, p. 178, pls. 3-4.

20. MOTTLED WILLOW BORER.

. 1895—Howard, L. O., Insect Life, Vol. 7, March, p. 360.

. 1895—Howard, L. O., Insect Life, Vol. 7, July, p. 430.

. 19802—Kirkland, A. H., Bul. 31 n.s., U. S. Div. Ent., pp. 96-97.
. 19038—Felt, E. P., 18th Rept., N. Y. State Ent., pp. 110-111, pl.

6 fig. 1.

. 1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pp. 100-

103, pl. 16 figs. 6-9.

. 1907—Schoene, W. J., Bul. 286, N. Y. Geneva Agy. Exp. Sta.,

pp. 81-104, pis. 1-6.

. 1907—Schoene, W. J., Bul. 67, U. S. Bur. Ent., pp. 27-29.
. 1911—Forbes, S. A., 26th Rept., Ill. State Ent., pp. 40-44,

figs. 43-47.

. 1911—Forbes, S. A., Bul. 151, Ill. Agr. Exp. Sta., pp. 502-506,

figs. 43-47.
21. PIGEON TREMEX.

. 1883—Saunders, Wm., Insect Injurious to Fruits, p. 141, figs.

147-148. J. B. Lippincott Co., Philadelphia. $2.00.

. 1888—Riley, C. V., Insect Life, Vol. 1, pp. 168-179, figs. 36-39,

pl. 1.

. 1890—Packard, A. S., Fifth Rept., U. S. Ent. Com., pp. 379-

381, fig. 41.
1906—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, pg
61-64, fig. 56.

22. BLACK CARPENTER ANT.

1905—Felt, E. P., Memoir 8, N. Y. State Mus., Vol. 1, p. 90, pl
al.

1909-—Pricer, John L., Biol. Bul., Marine Biol. Lab., Woods
Holl, Mass., Vol. 14, pp. 177-218, Bibl.

1911-—Felt, E. P., 26th Rept., N. Y. State Ent., pp. 57-58,
pis 19-20.

LESSON 10

NOTES

The lessons upon the shade tree insects, like the lessons upon
the tree diseases, must necessarily be more technical, and conse-
quently more difficult, than the other lessons of the course.

In the preparation of these lessons, it has been our aim to
make them simple and brief yet contain as much practical informa-
tion as possible that will help you in your work and in studying the
references given in the bibliography.

The lessons are not intended simply for study while you are
taking the course and answering the examination questions, but
they are intended also for future reference while working as a Tree
Surgeon.

Entomology was first studied as a past time or as a pure
science. It had to do largely with the study of the dead insects,
classifying and naming them or arranging them into collections
for exhibition purposes. This is now generally spoken of as sys-
tematic entomology.

Economic entomology, as now understood, is a new science
and does not date much beyond 1850. It deals with the insects in
their relation to man together with the means used for controlling
them. Such a great advance has been made in this subject within
the past few years that it now ranks ahead of the older, more tech-
nical side of the subject.

However, the two subjects are so closely related that they can
no more be separated than the bookkeeping system can be separ-
ated from the manufacturing end of a large corporation.

The insects must be named and classified and the scientific
name recorded, together with the descrpition of the species, or we
cannot tell whether the insect which we are studying is the same
as the one described in the literature.

The two subjects are so closely related that many of the tech-
nical terms used in both sciences must be learned before the liter-
ature can be understood.

Study the rest of your Elementary Entomology and where
possible collect and study the insects as outlined in the back of this
book. Pay special attention to the external anatomy and to the
structure of the mouth parts. It will be impossible for you to de-
cide upon the correct remedy, in many cases, without knowing how
the insect takes its food.

In studying these lessons, refer frequently to Lesson 8 until
you understand the use of the remedies, there described, in control-
ling the different insects. Also review your earlier lessons, in your
Elementary Entomology, until you know the characteristics of the
different orders.

The bibliography furnished with the lessons will help you in
getting additional literature upon the different species.

Cornell University Library

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