Elm leaf beetle and white-marked tussock moth

Q

ucation Department Bulletin

%J
* /CP/^1 I

ublished fortnightly by the University of the State of New York

as second-class matter June 24, 1908, at the Post Office at Albany, N. Y., under
the act of July 16, 1894

ALBANY, N. Y.

JANUARY 15, 1912

New York State Museum

JOHN M. CLARKK, Director
EPHRAIM PORTER FELT, State Entomologist

^ Museum Bulletin 156

ELM LEAF BEETLE AND WHITE-MARKED
TUSSOCK MOTH

BY

if

EPHRAIM PORTER FELTD.Pc.

PAGE

Introduction 5

Elm leaf beetle 6

Results of attack 7

Food plants 7

Distribution 7

Description 8

Life history 9

Natural enemies 10

Preventive measures.. 10

Remedial measures

White-marked tussock moth,

Description

Life history and habits . . .

Food plants

Natural enemies

Remedies

Explanation of plates

Index. .

PAGE
. II

• 14

• 15

• 15

. 16
. 16
. 16
. 19

• 35

ALBANY

UNIVERSITY OF THE STATE OP NEW YORK
1912

Me2r-Api2-20oo

EXCHANGE

Neiv York State Education Department

Science Division, April 4, 1912

Hon. Andrew S. Draper LL.D.

Commissioner of Education

SIR : I have the honor to submit herewith a revision of our State
Museum Bulletin 109 relating to the elm leaf beetle, the tussock
moth and their depredations upon our shade trees. The demand
for information on these insect pests is large and the last
edition of 'the bulletin is now exhausted. I therefore recommend
this manuscript for publication.

Very respectfully

JOHN M. CLARKE

Director

STATE OF NEW YORK

EDUCATION DEPARTMENT

COMMISSIONER'S ROOM

Approved for publication this $th day of April

Commissioner of Education

Education Department Bulletin

Published fortnightly by the University of the State of New York

Entered as second-class matter June 24, 1908, at the Post Office at Albany, N. Y., under

the act of July 16, 1894

No. 511 ALBANY, N. Y. JANUARY 15, 1912

New York State Museum

JOHN M. CLARKE, Director
EPHRAIM PORTER FELT, State Entomologist

Museum Bulletin 156

ELM LEAF BEETLE AND WHITE-MARKED TUSSOCK

MOTH

BY

EPHRAIM PORTER FELT D.^Sc.

The elm leaf beetle and the white-marked tussock moth must
be ranked among the most important leaf feeders affecting the
shade trees of cities and villages in New York State. They
have been responsible for widespread injury to thousands of
trees in recent years, while earlier experience shows that we
must reckon with these species if we would preserve the
beauty of our trees. Experience in the past has demonstrated
beyond all question the practicability of checking both of these leaf
feeders by spraying, an operation which is not very costly if
modern apparatus be employed. We are forced to conclude
therefore that extensive injury by either of these pests must be
attributed to indifference or culpable neglect rather than in-
ability, despite the fact that many appear very eager to take up
the warfare at a time when the ravages are most apparent and
unfortunately when repressive measures can be employed to
very little advantage.

There is a tendency on the part of many private individuals
to attribute their woes to the neglect of adjacent shade trees on
public streets, and conversely municipal authorities are prone to
state that injury to public trees is due to the pests swarming
thereto from neglected private grounds. The facts of the case
are that both of these insects are very local in habit. This is a

333209

YpRj£ STATE JV^USEUM

•

necessity in the case of the tussock moth, because the female is
wingless and as a consequence the species relies for dissemina-
tion on the very limited crawling powers of the caterpillar or
upon being carried by other agencies. The elm leaf beetle, on
the contrary, flies readily, but for some reason or other it is very
local in its habits and not infrequently one may see magnificent
trees infested with hordes of beetles and larvae, while within a
block, sometimes within 50 feet, other elms may be practically
free from the pest. These facts are of greatest importance to
all interested in the welfare of shade trees, since they demon-
strate beyond question the possibility of protecting the trees on
our public streets, irrespective of what is done by private
citizens, or conversely, the practicability of keeping the pest in
check on private grounds, even though there is little or no re-
pressive work upon those adjacent.

Elm leaf beetle

Galerucella luteola Mull

The ravages of this dangerous enemy to elms has been par-
ticularly severe in recent years. The damage has doubtless been
accentuated in numerous instances by exceptionally dry weather
and possibly by extremely low winter temperatures. These two
factors afford no adequate explanation for the great increase in
the number of injured trees, and particularly for the general de-
struction of the foliage so conspicuous in many communities in
1910 and 1911. It is very probable that the extension of electric
car service and the more general use of automobiles have been
of material service in disseminating a local and exceedingly
prolific insect, since both of these vehicles usually traverse tree-
lined streets and afford abundant opportunities for the collection
and dissemination of the beetles and thus greatly increase the
damage along favorite routes of travel.

This pest was so abundant and injurious from 1896 to 1899
in the cities of Albany and Troy as literally to compel some
action or a very large proportion of the elms would have been
destroyed. The insect made such headway in these cities that
it ruined or killed about 3000 elms before the end of 1900, and it
is more than probable that at least 1000 additional succumbed
the following decade. The earlier spraying against this pest
produced for the most part very satisfactory results, while the
treatment in recent years has given indifferent returns in man}'

ELM LEAF BEETLE AND WHITE-MARKED TUSSOCK MOTH 7

instances. An examination of conditions in several communities
in the summer of 1911 forced us to 'the conclusion that most of
the poor results following- spraying were due to careless or
slovenly work. It was a rather common occurrence to find the
lower limbs fairly well sprayed, while the upper branches were
almost untouched by the poison and, as a consequence, severely
injured by the beetle.

Dead foliage in midsummer, a weakened or dying condition
of the trees, and the vacant spaces formerly occupied by elms,
are in most instances the direct result of injury by this per-
nicious beetle, though all conversant with the situation must
admit that leaking gas and electricity have killed some trees
in many communities. The number destroyed by these latter
two agencies is small compared to those succumbing to insect
depredations. Old age has been advanced by some as a reason
for the death of many elms. This is hardly an adequate explana-
tion, since many 'trees which have perished were comparatively
young. Authentic records show that the American elm may
live from 150 to 200 years. Under favorable conditions it
should thrive for at least a century and in many instances for
a century and a half. It is lamentable that so many magnifi-
cent elms, representing the growth of several generations, and
in many instances occupying commanding positions and addine
greatly to the beauty and value of the adjacent property, should
be destroyed within a few years by an insect which may be
controlled at a comparatively small expense.

Results of attack. Elms losing two crops of leaves a season
for three or four years are invariably seriously affected and some
at least may die. The injury is almost as severe if the first crop
of leaves is destroyed so late that very little new foliage de-
velops the latter part of the season. This condition was rather
general with American elms in 1911 and may have resulted in part
from the weakened condition of the trees, an outcome of earlier
injuries.

Food plants. This leaf feeder displays a marked preference
for the more tender foliage of the English and Scotch elms,
though after the beetle has become abundant, it is frequently exceed-
ingly destructive to the American elm. Its operations on this
latter tree have been especially severe in the city of Watervliet
and in villages in the upper Hudson valley.

Distribution. This pest has now attained an extensive distri-
bution in this country, ranging from north of Salem, Mass., to Char-

8 NEW YORK STATE M,USEUM

lotte, N. C, and westward into Ohio and Kentucky. It occurs
in most of the cities and villages in the Hudson valley, having
made its way north to Glens Falls arid Ticonderoga and along
the Mohawk valley at least to Amsterdam. It has become well
established at Elmira and Ithaca and has been known for some
years in Oswego, though it does not appear to have been par-
ticularly destructive in that city. There is no record known to
us of this species occurring in Utica, Syracuse, Rochester or
Buffalo, though it is rather surprising that it has not already
become established in all of these cities.

Description. The skeletonized brown appearance of the fol-
iage in midsummer is very characteristic of the work of this
pest, particularly in the eastern cities and villages of the State.
The irregular, oval holes about one-quarter of an inch in diam-
eter, eaten by the beetles in early spring, are another indication
of the work of this species.

The parent beetle may be recognized by reference to the
colored illustration [pi. i, fig. 5,6]. lit is about one-quarter of an
inch long, with the head, thorax and margin of the wing covers
a reddish yellow. The coal-black eyes and median spot of the
same color on the head are prominent. The thorax is marked
with a dorsal black spot of variable shape and with a pair of
lateral ovoid ones. The median black line on the wing covers is
widely separated from lateral stripes of the same color by green:
ish yellow. The wing covers are minutely and irregularly punc-
tured, bear a fine pubescence and at the base of each there is an
elongated, black spot in the middle of the greenish yellow stripe.
These markings are fairly constant in the beetle, though the
color is quite variable during life and changes more or less after
death. Many of the insects emerging from winter quarters have
the yellowish stripes of the wing covers nearly obliterated by
black.

The orange-yellow eggs [pi. i, fig. i] are usually deposited in
irregular rows side by side, forming clusters of from three to
twenty-six or more on the underside of the leaf. Each egg is
somewhat fusiform, attached vertically by its larger end and
with the free extremity tapering to a paler rounded point.

The recently hatched grub [pi. I, fig. 2] is about one-twentieth
of an inch long with the head, thoracic shield, numerous tuber-
cles, hairs and le^s jet-black. The skin is dark yellow but the
tubercles are so large and the hairs so prominent that the pre-
vailing color of the grub at this stage is nearly black. An increase

ELM LEAF BEETLE AND WHITE-MARKED TUSSOCK MOTH Q

in size, following molts, is accompanied by the stiff hairs be-
coming less conspicuous and the yellow more prominent, till
the grub becomes full grown [pi. I, fig. 3]. It is then about one-
half of an inch long, more flattened than in the earlier stages,
with a broad, yellowish stripe down the middle of the back and
with a narrower stripe of the same color on each side, these be-
ing separated by broad, dark bands thickly set with tubercles
bearing short, dark colored hairs. The dorsal yellow stripe is
broken on each side by a subdorsal row of black tubercles which
decrease in size posteriorly. The lateral yellow stripe includes
a row of prominent tubercles with dark tips bearing hairs of the
same, color. The under surface is yellowish.

The pupa [pi. i, fig. 4] is a bright orange-yellow, about one-
fifth of an inch long and with a very convex dorsal surface
which bears transverse rows of stout, inconspicuous hairs.

Life history. The transformations of this insect are so rapid
and so greatly influenced by local conditions 'that a man must
know what to expect or he will accomplish very little in fighting
the pest, because a substance effective against the beetles or grubs
may not kill the pupae and, after the larvae have begun to de-
scend, may be of no value. The beetles winter in attics, sheds,
belfries and other shelters. They emerge with the advent of
warm weather and may then be found on the walks during the
sunny portion of the day or at the windows of houses, trying to
escape. The last of April or early in May, with the appearance
of the foliage, the beetles fly to the elms and eat irregular holes
in the leaves. Some time is occupied in feeding before the
deposition of eggs, the latter may continue four and possibly
five or six weeks. The prolific beetles consume a large amount
of foliage during this time, depositing clusters of from three to
twenty-six or more eggs every day or two. Over half the total
number of eggs may be laid at the height of the season within
about twelve days; in 1898, from June I2th to 23d. A female
may produce over six hundred eggs.

The young grubs appear early in June or about five or six
days after the eggs have been deposited later in the season. They
feed on the under surface of the leaf, producing the familiar
skeletonization [pi. i, fig. 7] which is caused by their eating
the softer underpart, leaving the veins and the upper epidermis
practically untouched. The results of their feeding are so
marked that it is easy to detect the presence of the grubs by the

IO NEW YORK STATE MUSEUM

semitransparent patches in the foliage. These latter soon dry
and turn brown.

There are two and occasionally three generations of this de-
structive insect in the latitude of Albany, the number depending
to a considerable extent upon the availability of suitable food.
The grubs complete their growth in from fifteen to twenty days,
descending limbs and trunk to a great extent in search of some
shelter under which to pupate. Seven days are spent in this
latter state in warm July weather, while in September it is ex-
tended to twelve and in October to twenty-four days. The grubs
of the first brood usually forsake the trees in Albany by the last
of June or early in July, and beetles belonging to the second
generation may begin depositing eggs about the middle of July,
and from then to late in autumn it is generally possible to find
this insect in all stages in some part of Albany. The beetles of
the second brood are naturally attracted to fresh foliage and
consequently more eggs are usually deposited on trees which
have been defoliated earlier in the season than upon others.

Badly infested trees are therefore very likely to lose two crops
of leaves in a season and may possibly have their third seriously
marred by this pest. The second brood of grubs completes its
growth about the middle of August, beetles appearing the latter
part of the month, and if there is an abundant supply of fresh
leaves, a third generation may appear in considerable numbers.
This last brood more frequently occurs in near-by trees which
have not been severely injured earlier in the season.

Natural enemies. This leaf feeder is subject to attack by a
number of natural enemies, most of which, however, are of com-
paratively little importance in keeping it in check. The common
garden toad will devour many beetles, and the much despised
English sparrow also feeds upon these insects to some extent.
Several predaceous insects prey upon this pest to a certain
degree.

Preventive measures. There are measures of considerable
value in the prevention of insect depredations, and there is no
reason why such should not be applied to the shade tree problem.
It is a mistake to have half to three-fourths of all the shade
trees in a city or village one species, especially if mostly on
contiguous streets. This is true of many localities where
the elm leaf beetle has caused very serious injury during the
last few years. The American elm and sugar maple, both

ELM LEAF BEETLE AND WHITE-MARKED TUSSOCK MOTH II

deservedly favorites for shade and park trees, may well give
way in part at least to other desirable, species, such as the Nor-
way maple, an excellent tree in many ways and practically free
from the insect pests so injurious to the sugar and the white or
silver maple. The last named has been extensively used in
many localities, and though brittle and liable to injury by wind
and ice, usually keeps in excellent condition for a number of
years. The red maple is also a valuable tree. The American
basswood or linden, the horsechestnut, the European plane tree
or buttonwood, the American ash and oaks, especially the pin
oak, red oak and scarlet oak should be set more freely. The
Ailanthus (pistillate trees) and the Carolina poplar, though pos-
sessing serious drawbacks, are desirable under certain condi-
tions. This diversified planting would admit the use of one
species on a street, and if adjacent streets were set with differ-
ent varieties, such an arrangement would go far toward reduc-
ing the possibility of extended outbreaks by injurious insects or
fungous diseases.

The proper care of trees, including judicious selection so as to
secure the best adaptation to local conditions, is an important
factor in forestalling insect ravages. Trees in full vigor are
better able to sustain injury and are usually less troubled by in-
sects than those in a debilitated condition. Certain progressive
communities have already recognized this need and have met it
in a more or less satisfactory manner. The city of Newark,
N. J., with a population of 347,469, expends for tree work (which
latter is separate from park work) about $27,000 a year, $6000
of this being for pruning, $6000 for spraying and $15,000 for
setting out new trees, maintenance etc. East Orange, N. J.,
with a population of only 34,371, expended in 1909 over $10,000
through its shade tree commission, $1200 of this being a special
appropriation for spraying elms. The city of Buffalo has re-
cently placed the care of its trees in the hands of a forester and
there is no reason why other communities should not adopt
equally comprehensive measures. Spraying alone is not suffi-
cient. There should be wise planting, judicious pruning and
liberal fertilization whenever necessary.

Remedial measures. The secret in controlling this insect lies
in understanding thoroughly its life history and appreciating
the vulnerable points. A thorough spraying with a poison early
in the spring, when the leaves are half out or larger, is most

12 NEW YORK STATE MjUSEUM

effective in preventing breeding, as the beetles are de-.
stroyed before they can deposit many eggs. Arsenate of lead is
by far the best poison and should be used at the rate of four pounds
(15 per cent arsenic oxid) to fifty gallons of water. Fortunately the
beetles are rather local in habit and as a consequence individual
trees or groups of trees may be protected to a very large extent
even if there are neglected ones in the near vicinity. The local
spread of this pest is slow and this should be taken advantage
of to the greatest possible extent by keeping the insect in control
wherever it occurs, even though the infestation be a small one
and the present injury of comparatively little importance. It is
a mistake on the part of local authorities to wait till this enemy
of the elms has become well established and destructive before
repressive measures are undertaken.

The grubs feed almost exclusively on the under surface of
the leaf, rarely occurring upon its upper side. The first injury
is usually on the upper more tender leaves, hence there is great
need of spraying the tops of the trees, and in order to kill the de-
structive grubs it is essential that the poison be thrown on the
underside of the foliage. Spraying with an arsenical poison for
the destruction of grubs is satisfactory only when the application
is early, as it is hardly advisable to spray for this insect when the
grubs are nearly full grown, since they are liable to desert the
tree even when slightly underfed and complete their transforma-
tions, rather than to eat distasteful foliage.

The ideal spray for this pest is a fine mist applied to the under
side of all the leaves. It is impossible to throw such a spray
any distance, and owing to the great height of most elms, such
treatment is impractical. A moderately coarse spray which can
be thrown 25 to 40 feet has been usually employed in connection
with ladders or the use of a high tower. The latter is practical
only where the streets are fairly level. The recent development
in the use of a solid stream and pressures of between 200 and
300 pounds for gipsy moth work has greatly reduced the cost of
applications in woodlands, and the system is now being applied
to shade trees with a corresponding saving in time and expense.
This method necessitates the use of more poison, there is in-
creased dripping and the throwing of the spray upon the foliage
is not so readily controlled. These are grave though not insur-
mountable objections, and for the present we are inclined to
favor a moderately coarse spray with the use of ladders or a
tower as the most practical method of spraying shade trees.

ELM LEAF BEETLE AND WHITE-MARKED TUSSOCK MOTH 13

Communities usually fail to realize that in the elm leaf beetle
we are dealing with an insect extremely sensitive to poison
and one which will feed upon sprayed leaves only when no others
are available. Its senses are so keen that it can detect poison
hardly visible with a powerful hand lens. Under such conditions
one may readily see how easy it is to secure indifferent results.
Spraying trees is a disagreeable, hazardous occupation, and in
order to secure the best returns, it is necessary to make the com-
pensation such as to result in a keen competition for the position
of nozzleman. The application of business principles would justify
larger municipalities placing this work in the hands of one who
understood at least the rudiments involved (a skilled landscape
gardener or forester would be even better) and giving him au-
thority to insist upon any reasonable standards in methods and
operation. Such a person could reasonably be expected, if pro-
vided with sufficient funds, to keep the foliage of elms practically
intact throughout the season, even in sections where the elm
leaf beetle was excessively abundant or upon trees adjacent to
those badly injured by the pest. Many trees were badly injured
last year because there was so much difficulty in securing men
who would do thorough work, a prime essential in an under-
taking of this kind.

The effective spraying season extends from early to middle
May till nearly the latter part of June, a total of approximately
six weeks. Making allowances for interruptions by rain, we
can hardly expect more than thirty full working days during
this period. A power spraying outfit of the usual type and
provided with two lines of hose can spray thoroughly, perhaps
fifty trees a day or a maximum of 1500 during the season as
restricted above, much depending upon the size and location of the
trees as well as the efficiency of the men in charge.

The cost of thorough spraying is not excessive. It may be esti-
mated at about 50 cents a tree or only 10-20 cents a tree if all
the work be done from the ground with a high power outfit, in
each case making no allowance for the cost of apparatus. A
power spraying outfit adapted to shade tree work can hardly
be obtained for less than $275 to $500, and in case of the high
pressure outfits, may easily amount to more than double the
latter sum. There should be plenty of power, an abundance of
hose and good ladders unless it is planned to do all the work
from the ground. This work can be done with a powerful hand
pump at a greater cost for operation though the initial expense

14 NEW YORK STATE M,USEUM

($30 — $50) is much less. It is extremely desirable, where conditions
permit, for a community to provide not only for the spraying of the
"street trees, but also to arrange for the care of those on private
grounds at a nominal cost.

The full-grown larvae crawl down the trunks in great num-
bers and the golden yellow pupae may be found in abundance in
crevices in the bark and on the ground about the tree. A good
proportion of the insects can be forced to take refuge on the
ground by scraping off the rough bark, thus depriving them of
shelters upon the tree. Large numbers can then be killed when
assembled about the base of the tree by spraying them with a
contact insecticide such as kerosene emulsion, whale oil soap
solution or even by pouring boiling water on them. The
grubs should be destroyed in the manner indicated every five
days so long as the pests are seen in numbers, in order to secure
the best results. This method of fighting the pest is advisable
only when it is impossible to employ the more satisfactory
arsenical sprays. Bands of tar, sticky fly paper, cotton batting,
etc., while they do no harm, can not be considered of much value
in keeping the elm leaf beetle under control. The relatively few
grubs caught on a sticky band are but a drop in the bucket com-
pared with the masses which complete their transformations
either above or below. It is worse than useless to attempt to
control this or any other insect by boring a hole in the trunk of
a tree and inserting therein compounds of any nature. The tree
is weakened and unless the chemical be powerful enough to kill
it, the insects are not affected.

White-marked tussock moth.

Hemerocampa leucostigma Abb. & Sm.

This insect, preeminently a pest on city and village trees,
occasionally proves a veritable scourge over considerable areas.
Some cities appear to be more afflicted in this way than others.
The summer of 1906 was marked by extensive depredations in
a number of cities and villages throughout the State, thus dupli-
cating the experience of 1898. It will therefore be seen that seri-
ous injuries by this caterpillar are more or less periodic. This
is to be explained by the fact that the species has a number of
natural enemies which assist materially in keeping it under con-
trol. The destructive outbreaks are examples of what might
occur annually were there no parasites to check the work of this

ELM LEAF BEETLE AND WHITE-MARKED TUSSOCK MOTH 15

voracious leaf feeder. The cause of this native species thriving
so greatly in cities and villages during recent years is explained
by the abundance of the English sparrow. This bird will not
eat the caterpillars and drives away many of the native forms
which, in earlier days, were of great service in devouring these
hairy pests.

Description. The full-grown caterpillar is really a beautiful
object. It has a coral-red head, a pair of long, black plumes just
over it, a single one at the opposite extremity of the body, four
delicate yellowish or white, brushlike tufts on its back and just
behind them, separated only by a segment, two small retractile
red elevations. There is a broad, black band broken only by
tubercles and tufts along the back and bordered by yellowish
stripes. Each side is dark gray except for the yellowish tuber-
cles. The breathing tubes or spiracles are in a lateral black
line and below this the caterpillar is yellow, the legs usually be-
ing paler [pi. 2, fig. 4]. The very young caterpillar is pale yel-
lowish or whitish with long, irregular hairs. It increases in
size, casts its skin from time to time and assumes one after
another the characteristics of the full-grown larva.

The thin cocoons spun in the crevices of the bark [pi. 2, fig. 6]
have the long hairs of the caterpillar interwoven and within this
shelter the larva transforms to a yellowish white pupa more or
less shaded with dark brown or black [pi. 2, fig. 7].

The sexes differ strikingly as is shown on plate 2, figures I
and 2. The male is a beautiful moth with large feathery anten-
nae, tufted legs, and with the wings and body delicately marked
with several shades of gray or grayish white. The female, on
the other hand, is a nearly uniform gray with simple antennae
and but rudimentary wings.

The eggs, usually over three hundred, are deposited on the
empty cocoon, under a conspicuous white mass of frothy matter
about one-half of an inch in diameter [pi. 2, fig. 3]. This soon
hardens and forms a very effective protection. The egg masses
[pi. 7, 8] are easily removed and a tree thoroughly cleared
thereof can become infested again only by caterpillars crawling
from adjacent trees or being carried thereto. The individual egg
is nearly spheric, about one-twenty-fifth of an inch in diameter,
white or yellowish white and with a light brown spot surrounded
by a ring of the same color.

Life history and habits. This insect winters in the conspic-
uous egg masses described above, the young appearing about

l6 NEW YORK STATE MUSEUM

the latter part of May in this latitude. They feed at first on the
more tender lower epidermis of the leaf and soon devour all but
the principal veins. The small caterpillars frequently hang
by a silken thread and continued jarring may cause many
to drop to the ground. "Feeding and growth occupy a month or
more, pupation occurring the latter part of June or early in July.
There is some deviation from this, as a few individuals spin up
early and some caterpillars linger till numerous egg clusters indi-
cate that most of the insects have completed the round of life.
The pupal stage occupies from ten to fifteen days. The wingless
female appears at the end of this period, crawls on her co-
coon and shortly deposits eggs as described. There is normally
but one generation annually in Albany and other inland cities,
while in New York City and vicinity and in Boston, Mass., there
are two broods and at Washington, D. C., there are three gen-
erations each year as stated by Doctor Howard.

The young caterpillars drop from the tree readily, suspend
themselves by silken threads and then may be blown or carried
considerable distances. The full-grown caterpillars desert the
trees and wander considerably. This is particularly true of the
larger ones which almost invariably produce female moths. The
cocoons are spun very generally on the trunks or on the under-
side of the larger branches.

Food plants. This leaf feeder exhibits a marked preference
in cities for the linden and horse-chestnut, while it feeds readily
on elms and maples. It has also been recorded on a number of
other trees.

Natural enemies. This species has a number of natural ene-
mies. Its comparative rarity in the country shows that our
native birds must be very efficient natural checks upon this in-
sect. Mr E. H. Forbush states that forty-seven species of native
birds feed on hairy caterpillars, most of which would probably
take this leaf feeder. The robin, Baltimore oriole and cuckoo
are among the more valuable in this respect.

Parasitic insects are also very efficient checks. This species is
subject to attack by some twenty-one primary parasites and these
in turn may become the prey of fourteen hyperparasites.

Remedies. A simple and very satisfactory method of con-
trolling- this insect is the gathering and destroying of egg masses.
Several cities and villages in New York State have employed
children in this work by offering a small bounty and a system of
prizes. The result has been that a large number of egg masses

ELM LEAF BEETLE AND WHITE-MARKED '-fUSSpCj^MtrTH, \ 17

were secured and destroyed at a comparatively slight cost. The
defect in this method is that it is more* or less irregular in opera-
tion and is usually resorted to only after serious injury to the
trees has aroused public opinion. There is no doubt as to the
effectiveness of collecting egg masses and in not a few instances
it may prove the cheapest method of keeping this pest in
check. It would seem better for the welfare of the trees to
make some provision for the systematic collection of egg masses
from year to year from all the trees, even though the cost be some-
what greater.

The collection of egg masses should be supplemented, if un-
cleaned trees are in the vicinity, by banding the trunks at the
time the caterpillars begin to crawl, with some material which
will prevent the ascent of straggling larvae. A very simple
method is to take a band of cotton batting some six or eight
inches wide, wrap it around the tree, tie a string about its middle
and then turn the upper edge down over the string. Tree tangle-
foot, a preparation made by the same company that manufac-
tures tanglefoot fly paper, has been used very extensively on
trees about Boston. It is very adhesive, remains sticky for a con-
siderable time and does not injure the bark of older trees at least.

The tussock moth caterpillar succumbs readily to arsenical
poisons and where the trees are infested or are likely to be at-
tacked by more than one leaf feeder, as is true in the Hudson
valley, spraying is perhaps the best method of protecting the
trees. One of the best poisons for this purpose, particularly in
sections infested by the elm leaf beetle, is arsenate of lead, (15
per cent arsenic oxid), used at the rate of four pounds to fifty gal-
lons of water.

EXPLANATION OF PLATES
Plate i

Executed from nature, under the author's direction, by L. H.
Joutel of New York City, and reproduced from the 5th report of
the Commissioners of Fisheries, Game and Forests through the
courtesy of the commissioners

19

Elm leaf beetle

Galerucella luteola Miill.

1 Cluster of eggs, much enlarged

i a Side view of single egg, still more enlarged

2 Recently hatched larva or grub, much enlarged

3 Full-grown larva or grub, much enlarged

4 Pupa, much enlarged

5 Overwintered beetle, much enlarged

6 Fresh, brightly colored beetle much enlarged

7 Leaf showing eating of larvae or grubs and a few holes eaten

by beetles, eggs in clusters, cast larval skins and full-grown
larvae, natural size

8 Leaf skeletonized by grubs

9 Leaf eaten by beetles

20

PLATE 1

"'

L. H. joutei, 1900, ELM LEAF BEETLE

(Reprint from 5th report of commissioners of fisheries, game and forests)

Plate 2

Executed from nature by L. H. Joutel
21

White-marked tussock moth
Hemerocampa leucostigma Abb. & Sm.

1 Male moth at rest on trunk

2 Female laying eggs upon her cocoon

3 Egg masses on cocoons

4 A full-grown caterpillar resting on a twig

5 Cast skins of caterpillars

6 Cocoons massed on trunk

7 Pupa of female within cocoon

8 Twigs girdled by caterpillars

8a Twig broken off at point of girdling

The foliage shows the effects of this caterpillar's work

22

PLATE 2

L. H. Joutel, 1906.

WHITE MARKED TUSSOCK MOTH

Plate 3

23

A magnificent English elm nearly defoliated by the elm leaf
beetle, Galerucella luteola Miill. Lancaster street,
Albany. Photo August 1906.

Plate

Albany, Aug. 1906

Work of elm leaf beetle on Lancaster street

Plate 4
25

Row of English elms on South Hawk street, Albany, nearly
ruined by the work of the elm leaf beetle, Galerucella
luteola Mull. Photo August 1906. These nine trees were,
in 1898, in about the same condition as the one illustrated on
plate 3.

26

Plate 4*

Albany, Aug. i >

Work of elm leaf beetle on South Hawk street

;-•»••,

f %• ': . •:

Plate 5

27

American elm on Washington avenue near Fort Orange Club,
Albany, seriously injured by the elm leaf beetle, Galerucella
luteola Mull. Photo August 1906. Note the numerous dead
limbs. This tree died about two years later.

28

Albany, Aug. 1906

Work of elm leaf beetle on Washington avenue

Plate 6

29

Work of white-marked tussock moth, H e m e r o c a m p a
leucostigma Abb. & Sm., on clump of horse-chestnuts
standing on the grounds of St Francis de Sales Asylum, Albany.
Photo August 1906.

Plate 7

Egg masses of white-marked tussock moth H e m e r o -
campa leucostigma Abb. & Sm., on American elm.
Congress street, Albany. Photo August 1906. Note that the egg
masses are conspicuous, attached to slight cocoons and therefore
easily removed.

32

Plate 7 V AL.: :' vK'A :/•'•

Albany, Aug. 1906
White-marked tussock moth eggs on Spring street

Plate 8

33

Egg masses of white-marked tussock moth, H e m e r o -
cam pa leucostigma Abb. & Sm., on English elm,
Capitol park, Albany. Photo August 1906. Note that the egg
masses are conspicuous, attached to slight cocoons and therefore
easily removed.

34

Plate 8 '•

Capitol Park, Albany, 1906

White-marked tussock moth eggs

INDEX

Arsenate of lead, 9, 12, 17.

Birds, feeding on white-marked
tussock moth, 16; on elm leaf
beetle, 10.

Cotton batting, 14.

Elm leaf beetle, 6-14; description, 8-
9 ; distribution, 7-8 ; food plants, 7 ;
life history, 9-10; natural enemies,
10 ; remedial measures, 11-14.

Fly paper, 14.

Galerucella luteola, 6-14.

Hemerocampa leucostigma, 14-17.

Kerosene emulsion, 14.

leucostigma, Hemerocampa, 14-17.
luteola, Galerucella, 6-14.

Parasites, white-marked tussock
moth, 16.

Remedies, arsenate of lead, 12, 17;
cotton batting, 14; flv paper, 14;
kerosene emulsion, 14; tar bands,
14; whale oil soap solution, 14.

Tar bands, 14.

Tussock moth, see White-marked
tussock moth.

Whale oil soap solution, 14.

White-marked tussock moth, 14-
17; description, 15; food plants,
16; life history and habits, 15-16;
natural enemies, 16; remedies, 16-

35

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