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EXCHANGE




- Published monthly by the

New York State Education Department



MAY 17



BULLETIN 397



MARCH 1907



New York State Museum

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



Bulletin 109
ENTOMOLOGY 27



WHITE MARKED TUSSOCK MOTH AND ELM
LEAF BEETLE



BY



EPHRAIM PORTER FELT D.



Introduction 5



White marked tussock moth. . .

Description

Life history and habits :

Food plants

Natural enemies

Remedies .'.



' UNIVERSITY



Elm leaf beetle 9

^Foqd plants 10

Distribution 10

Description 10

Life history 12

Natural enemies 13

Remedial measures 13

Explanation of plates 15

Index 31



ALBANY

NEW YORK STATE EDUCATION DEPARTMENT
1907



Met2 7 in-N6-2



Price 20 cents



EXCHANGE

STATE OF NEW YORK
EDUCATION DEPARTMENT



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Regents of the University '



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With years when terms expire

1913 WHITELAW REID M.A. LL.D. Chancellor - - - New York
1917 ST CLAIR MCKELWAY M.A. LL.D. Vice Chancellor Brooklyn
1908 DANIEL BEACH Ph.D. LL.D. - Watkins

igi.4. .PLINX T^ Sj^ercjN LL.B. LL.D. - Palmyra

* ' S



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Ph.D. L.H.D. LL.D. D.C.L. New York

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Commissioner of Education

ANDREW S. DRAPER LL.B. LL.D.

Assistant Commissioners

HOWARD J. ROGERS M.A. LL.D. First Assistant
EDWARD J. GOODWIN Lit.D. L.H.D. Second Assistant
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Secretary to the Commissioner

HARLAN H. HORNER B.A.

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Statistics, HIRAM C. CASE

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New York State Education Department

Science Division, October 31, 1906

Hon. Andrew S. Draper LL. D.

Commissioner of Education

MY DEAR SIR: I communicate herewith for publication as a
bulletin of the State Museum a paper of immediate importance by
the State Entomologist, entitled the White Marked Tussock Moth and
Elm Leaf beetle.

Very respectfully yours

JOHN M. CLARKE

Director

State of New York
Education Department

COMMISSIONER'S ROOM
Approved for publication, November 3, 1906




Commissioner of Education



048583



New York State Education Department

New York State Museum

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



Bulletin 109

ENTOMOLOGY 27 ' /, ; .,.,,>,,,, ,



WHITE MARKED TUSSOCK MOTH AND
ELM LEAF BEETLE



BY
EPHRAIM PORTER FELT D. Sc.

These two insects must be ranked among the most important leaf
feeders affecting the shade trees of cities and villages in New York
State. They were responsible during the season of 1906 for wide-
spread injury to thousands of trees, and the experience of earlier
years shows that we must reckon with these species if we would
preserve the beauty of our trees. Both of these pests, despite their
destructiveness, are controlled with relative ease. The tussock moth
can be readily suppressed in at least two ways, while the elm leaf
beetle succumbs quickly to timely applications of arsenical poisons.
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 inability, 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



6 NEW YORK STATE MUSEUM

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 necessity in the case
of the tussock moth, because the female is wingless and as a conse-
quence the specie's relies for dissemination on the very limited
crawling powers of the caterpillar or upon their being carried by
other agencies. ..The elm leaf beetle, on the contrary, flies readily,
for s^^^y^sQ-n or other it is very local in its habits and not
55 one may see magnificent trees infested with hordes of
uyafe/vftiile 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 demonstrate 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 little or no repressive
work is done upon those adjacent.

White marked tussock moth
Hemerocampa leucostigma Abb. & Sm.

This insect, preeminently a pest on city and village trees, occa-
sionally proves a veritable scourge over considerable areas. Some
cities appear to be more afflicted in this way than others. Buffalo
seems to have been specially unfortunate in the last six or seven
years. 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 serious
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 in subjection. The
destructive outbreaks are examples of what might occur annually
were there no parasites to check the work of this 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.



WHITE MARKED TUSSOCK MOTH AND ELM LEAF BEETLE 7

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 deli-
cate yellowish or white, brushlike tufts on its back and just behind
them, separated only by a segment, two small retractile red eleva-
tions. 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 tubercles. The breathing
tubes or spiracles are in a black line and below this the caterpillar
is yellow, the legs usually being paler [pi. i, fig. 4]. The very young
caterpillar is pale yellowish 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. i, 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 [pL i, fig. 7].

The sexes differ strikingly as is shown on plate i, figures i and 2.
The male is a beautiful moth with large feathery antennae, 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 300, are deposited on the empty cocoon,
under a conspicuous white mass of frothy matter about ^2 inch in
diameter [pi. i, fig. 3]. This soon hardens and forms a very
effective protection. The egg masses [pi. 4, 5] 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 */*$ 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 conspicuous
egg masses described above, the young appearing about 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 caterpillars while young 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



8 NEW YORK STAT MUSEUM

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 indicate that most of the insects
have completed the round of life. The pupal stage occupies from
10 to 15 days. The wingless female appears at the end of this period,
crawls on her cocoon and shortly deposits eggs as described. There
is normally but one annual generation 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
generations each year as stated by Dr Howard.

A peculiar habit, first recorded by the late Dr Lintner and subse-
quently observed by us, is the girdling of the elm twigs by larvae of
this insect. This is caused by their eating a portion of the bark
around the twig near the beginning of the season's growth [pi. i,
fig. 8]. The affected tips soon die, break off and fall in numbers to
the ground. The young caterpillars drop from the tree readily, sus-
pend 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 underside 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 enemies.
Its comparative rarity in the country shows that our native birds
must be very efficient natural checks upon this insect. Mr E. H.
Forbush states that 47 species of native birds feed on hairy cater-
pillars, most of which would probably take this leaf feeder. The
robin, Baltimore oriole and cuckoo are among the more valuable in
this respect.

Paj-asitic insects are also very efficient checks. This species is
subject to attack by some 21 primary parasites and these in turn
may become the prey of 14 hyperparasites.

Remedies. A simple and very satisfactory method of controlling
this insect is the gathering and destroying of egg masses. Several
cities and villages in New York State have employed children in this



WHITE MARKED TUSSOCK MOTH AND ELM LEAF BEETLE 9

work by offering a small bounty and a system of prizes. The result
has been that a large number of egg masses were secured and
destroyed at a comparatively slight cost. The defect in this method
is that it is more or less irregular in operation 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 keep-
ing this pest in cheek. 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
somewhat greater.

The collection of egg masses should be supplemented, if uncleaned
trees are in the vicinity, by banding the trunks at the time the cater-
pillars 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 6 or 8 inches wide, wrap it around the tree,
tie a string about its middle and then turn the upper edge down over
the string. Tree tanglefoot, a preparation made by the same com-
pany that manufactures tanglefoot fly paper, has been used very
extensively on trees about Boston. It is very adhesive, remains
sticky for a considerable 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 attacked by mgre
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 the prepared arsenate of lead, a compound specially
manufactured for this purpose. It can be applied in almost any
quantities without injuring the trees and is far more adhesive than
the commonly employed london purple, paris green or other copper
arsenites.

Elm leaf beetle

Galerucella luteola Mull.

This destructive beetle, like the white marked tussock moth dis-
cussed previously, is a most dangerous enemy to certain shade trees,
particularly in cities. It is in all probability responsible for more
ruined elms in the Hudson valley than all other destructive agencies
combined. It was so exceedingly abundant and injurious from 1896



10 NEW YORK STATE MUSEUM

to 1899 in the cities of Albany and Troy as to literally compel some
action, or a very large proportion of the elms would have been
destroyed. The insect obtained such a start in both of these cities
that it was able to destroy or ruin about 1500 elms in each before the
end of 1900. The vigorous measures employed both in Albany and
Troy have mitigated the plague very largely and have demonstrated
the practicability of keeping the insect in check. The results in
both cities are evident to any observer, because instead of a large
proportion of the elms having their leaves skeletonized and browned
in midsummer, as was the rule in 1896 to 1898, the work of this pest
is observed only here and there and is limited to sections where the
trees have not been thoroughly sprayed or to localities where neglect
is the rule. This was very well shown in the summer of 1906 in both
Albany and Troy. The effective work of earlier years had led many
to suppose that the elm leaf beetle was becoming less injurious and
consequently there was a decided relaxation in the efforts to control
this insect. A very large number of trees in both cities suffered
severely as a result of this partial cessation in control work.

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

Distribution. This pest has now attained an extensive distribu-
tion in this country-, ranging from north of Salem, Mass, to Char-
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 and along the Mohawk valley at least to
Schenectady. It has become well established at Elmira and Ithaca,
N. Y., and has been known for some years in Oswego, though it
does not appear to have been particularly 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 foliage
in midsummer is very characteristic of the work of this pest, particu-
larly in the eastern cities and villages of the State. The irregular,
oval holes about % inch in diameter, eaten by the beetles in early
spring, are another indication of the work of this species.



WHITE MARKED TUSSOCK MOTH AND ELM LEAF BEETLE II

The parent beetle may be recognized by reference to the colored
illustration [pi. 2, fig. 5, 6]. It is about ^ inch long, with the head,
thorax and margin of the wing covers a reddish yellow. The coal-
black eyes and median spot of the samt, color on the head are promi-
nent. 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 greenish yellow. The wing covers are minutely and
irregularly punctured, 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. 2, fig. i] are usually deposited in
irregular rows side by side, forming clusters of from 3 to 26 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. 2, fig. 2] is about /*> inch long
with the head, thoracic shield, numerous tubercles, hairs and legs
jet-black. The skin is dark yellow but the tubercles are so large and
the hairs so prominent that the prevailing color of the grub at this
stage is nearly black. An increase in size, following molts, is accom-
panied by the stiff hairs becoming less conspicuous and the yellow
more prominent, till the grub becomes full grown [pi. 2, fig. 3]. It
is then about 1 2 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 being sepa-
rated 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 pos-
teriorly. 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. 2, fig. 4] is a bright orange-yellow, about 1 5 inch
long and with a very convex dorsal surface which bears transverse
rows of stout, inconspicuous hairs.



12 NEW YORK STATE MUSEUM

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 descend, may be of no
value. The beetles winter in attics, sheds, outhouses 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 occu-
pied in feeding before the deposition of eggs, a process which 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 3 to 26 or more eggs every day or two. Over half
the total number of eggs may be laid at the hight of the season
within about 12 days; in 1898, from June 12 to 23. A female may
produce over 600 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 skeletoniza-
tion [pi. 2, fig. 7] which fs caused by their eating the softer under-
part, 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 semitransparent
patches in the foliage. These latter soon dry and turn brown.

There are two and occasionally three generations of this destruc-
tive 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 15 to 20 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 extended to 12 and in October to
24 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 conse-



WHITE MARKED TUSSOCK MOTH AND ELM LEAF BEETLE 13

quently 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 compara-
tively 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.

Remedial measures. The secret in controlling this insect lies
in understanding thoroughly its life history and appreciating the
vulnerable points. A thorough spraying with an arsenical poison
early in the spring, when the beetles begin to feed, is most effective
in preventing breeding, as the parent insects are destroyed before
they can deposit many eggs. 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 neg-
lected 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 com-
paratively little importance. It is a mistake on the part of local
authorities to wait till this enemy of the elms has become well estab-
lished 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 spray-
ing the tops of the trees, and in order to kill the destructive 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 advis-
able to spray for this insect when the grubs are nearly full grown,



14 NEW YORK STATE MUSEUM

since they are liable to desert the tree even when slightly underfed
and complete their transformations, rather than to eat distasteful
foliage.

The full grown larvae crawl down the trunks in great numbers
and the golden yellow pupae may be found in abundance in crevices
in the bark and on the ground about the tree. A great proportion


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Online LibraryEphraim Porter FeltWhite marked tussock moth and elm leaf beetle → online text (page 1 of 3)