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UNIVERSITY OF 
ILLHVOIS LIBRARY 
AT URBANA-CHAMPAIGN 
NATURAL HIST. SURVEY 


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EILLINOIS TREES AND SHRUBS: 


THEIR Insect Enemies 


ELE. t,. ENGLISH 


oo AMTURA, SEGVERY SUM 


eee) MAR 22 1999 


LIBRARY 


ILLINOIS NATURAL HISTORY SURVEY 
Circular 47 


Sixth Printing 


STATE OF ILLINOIS 


DEPARTMENT OF REGISTRATION AND EDUCATION 


BOARD OF NATURAL RESOURCES AND CONSERVATION 


RonauD E. STACKLER, J.D., Chairman; THOMAS PaRK, Ph.D., Biology; L. L. Stoss, 


Ph.D., Geology; 


HERBERT S. GuTOWSKY, Ph.D., Chemistry; RoBpERT H. ANDERSON, B.S.C.E., Engineering; STANLEY K, 
SHaPIRO, Ph.D., Forestry; W. L. Everirr, E.E., Ph.D., Representing the President of the University of 
Illinois; JOHN C. GUYON, Ph.D., Representing the President of Southern Illinois University. 


NATURAL HISTORY SURVEY DIVISION, Urbana, Illinois 


SCIENTIFIC AND TECHNICAL STAFF 
GEORGE SPRUGEL, JR., Ph.D., Chief 
ALICE K. ADAMS, Secretary to the Chief 


Section of Economic Entomology 


WILLIAM H. LUCKMANN, Ph.D., Entomologist and 
Head 

JAMES E. APPLEBY, Ph.D., Entomologist 

WiuuIs N. Bruce, Ph.D., Entomologist 

WayYNE L. Howe, Ph.D., Entomologist 

RONALD H. MEYER, Ph.D., Entomologist 

STEVENSON Moore, III, Ph.D., Entomologist, Ex- 
tension 

EDWARD J. ARMBRUST, Ph.D., Associate Entomolo- 
gist 

Marcos KoGANn, Ph.D., Associate Entomologist 

JOSEPH V. Mappox, Ph.D., Associate Entomologist 

ROBERT D. PauscH, Ph.D., Associate Entomologist 


RALPH E. SECHRIEST, Ph.D., Associate Entomolo- 


gist 
JOHN K. BOUSEMAN, M.S., Assistant Entomologist 
MICHAEL E. IRWIN, Ph.D., Assistant Entomologist 
DONALD E. KUHLMAN, Ph.D., Assistant Professor, 
Extension 
ROSCOE RANDELL, Ph.D., Assistant Professor, 
Extension 
WILLIAM G. RUESINK, Ph.D., Assistant Entomologist 
JAMES R. SANBORN, Ph.D., Assistant Entomologist 
DouGuas K. SELL, Ph.D., Assistant Entomologist 
C. RoBertT TAyuLor, Ph.D., Assistant Entomologist 
JOHN L. WEDBERG, Ph.D., Assistant Entomologist 
CLARENCE E. WHITE, B.S., Assistant Entomologist 
Kurt EK. ReEpBorG, M.S., Assistant Specialist 
JOHN F. WALT, M.S., Assistant Specialist, Extension 
JEAN G. WILSON, B.A., Supervisory Assistant 
LINDA ISENHOWER, Junior Professional Scientist 
STEPHEN ROBERTS, B.S., Junior Professional 
Scientist 
JOHN T. SHAW, B.S., Junior Professional Scientist 
DANIEL P. BARTELL, Ph.D., Research Associate 
BETTINA FRANCIS, Ph.D., Research Associate 
MARGARET ANDERSON, B.S., Research Assistant 
ROBERT J. BARNEY, B.S., Research Assistant 
Tzu-SUAN CHu, M.S., Research Assistant 
STEPHEN D. Cowan, B.S., Research Assistant 
MARION Farris, M.S., Research Assistant 
BONNIE IRWIN, M.S., Research Assistant 
JENNY KOGAN, M.S., Research Assistant 
Ros—E ANN MeEccout, B.S., Research Assistant 
BRIAN MELIN, B.S., Research Assistant 
CELIA SHIH, M.S., Research Assistant 
KatuHy Woop, M.S., Research Assistant 
JO ANN AUBLE, Technical Assistant 
LOWELL Davis, Technical Assistant 
CHARLES G. HELM, M.S., Technical Assistant 
Lu-PING LEE, M.S., Technical Assistant 


Section of Botany and Plant Pathology 


SEATS SUNN ERE, Ph.D., Plant Physiologist and 

ea 

EUGENE B. HIMELICK, Ph.D., Plant Pathologist 

R. DAN NEELY, Ph.D., Plant Pathologist 

D. F. SCHOENEWEISS, Ph.D., Plant Pathologist 

J. LELAND CRANE, Ph.D., Associate Mycologist 

WALTER HARTSTIRN, Ph.D., Assistant Plant 
Pathologist 

BETTY S. NELSON, Junior Professional Scientist 

GENE E. REID, Technical Assistant 


Section of Aquatic Biology 


D. HOMER Buck, Ph.D., Aquatic Biologist 
WILLIAM F. CHILDERS, Ph.D., Aquatic Biologist 
R. WELDON LARIMORE, Ph.D., Aquatic Biologist 
ROBERT C. HILTIBRAN, Ph.D., Biochemist 
ALLISON BRIGHAM, Ph.D., Assistant Aquatic 


Biologist 

WARREN U. BRIGHAM, Ph.D., Assistant Aquatic 
Biologist 

RICHARD E. SPARKS, Ph.D., Assistant Aquatic 
Biologist 


TED W. SToRCK, Ph.D., Assistant Aquatie Biologist 
JOHN TRANQUILLI, Ph.D., Assistant Aquatic 
Biologist 
MARY FRANCES BIAL, Junior Professional Scientist 
Cart M. THOMPSON, B.S., Junior Professional 
Scientist 
RICHARD J. BAuR, M.S., Research Associate 
DONALD W. DUFFORD, M.S., Research Associate 
JOHN M. MCNuRNEY, M.S., Research Associate 
HARRY W. BERGMANN, B.S., Research Assistant 
Kurt T. CLEMENT, B.S., Research Assistant 
LARRY W. CouTANT, M.S., Research Assistant 
HERBERT M. DREIER, M.S., Research Assistant 
MICHAEL A. FRAKES, M.S., Research Assistant 
THOMAS E. Hiuu, M.S., Research Assistant 
EARL THOMAS JOY, JR., M.S., Research Assistant 
RICHARD KOCHER, B.S., Research Assistant 
ROBERT MORAN, M.S., Research Assistant 
STEPHEN O. SWADENER, M.S., Research Assistant 
JANA LEE WAITE, M.S., Research Assistant 
STEPHEN W. WAITE, M.S., Research Assistant 
KATHRYN EWING, B.S., Technical Assistant 
SusAN Moore, Technical Assistant 
FLORENCE PARTENHEIMER, B.A., Technical Assistant 
WESLEY F. PorAk, B.S., Technical Assistant 
C. RUSSELL ROSE, Field Assistant 


Section of Faunistic Surveys and 
Insect Identification 


PuHiniep W. SMITH, Ph.D., Taxonomist and Head 
WALLACE E. LABERGE, Ph.D., Taxonomist 

LEWIS J. STANNARD, JR., Ph.D., Taxonomist 
GEORGE L. GODFREY, Ph.D., Associate Taxonomist 
DONALD W. WEBB, M.S., Associate Taxonomist 
LARRY M. PaGeE, Ph.D., Assistant Taxonomist 
JOHN D. UNZICKER, Ph.D., Assistant Taxonomist 
BERNICE P. SWEENEY, Junior Professional Scientist 
Brooks M. Burr, M.S., Technical Assistant 


Section of Wildlife Research 


GLEN C. SANDERSON, Ph.D., Wildlife Specialist and 
Head 

FRANK OC, BELLROSE, Sc.D., Wildlife Specialist 

WILLIAM R. Epwarpbs, Ph.D., Wildlife Specialist 

JEAN W. GRABER, Ph.D., Wildlife Specialist 

RICHARD R. GRABER, Ph.D., Wildlife Specialist 

HAROLD C. HANSON, Ph.D., Wildlife Specialist 


(Continued on Inside Back Cover) 


This paper is a contribution from the Section of Economic Entomology. 


(724247 M—5-—76) 


STATE OF ILLINOIS ® DEPARTMENT OF REGISTRATION AND EDUCATION 


NATURAL HISTORY SURVEY DIVISION ® GEORGE SPRUGEL, JR., Chief 


ILLINOIS TREES AND SHRUBS: 


THEIR Insect Enemies 


Ls brew Gls 8 


ILLINOIS NATURAL HISTORY SURVEY 


Cincelar 47 Printed by Authority of E ; 
Sixth Printing the State of Illinois GE, 
With Revisions SS 
(First Printing, 1958) 


URBANA 
May, 1976 


CONTENTS 


About Insects 5 . 
Aphids or Plant Lice : 
Scale Insects 
Borers er 
Leaf Eaters . 

Mites 
Gall- Producing “Insects 
and Mites . 2 
About Trees and Shrubs 
and Their Pests 4 

Ailanthus (Tree of Heaven) 
Ailanthus Webworm 
Cynthia Moth 

Arborvitae 
Bagworm . 

Arborvitae Leaf Miner 
Spruce Spider Mite 
Juniper Scale 

Ash . 

Red- Headed Ash Borer 
Ash Borer . 
Oystershell Scale : 

Fall Webworm 

Birch P 
Bronze Bir ch Borer 
Birch Skeletonizer 

Boxelder a EA 
Boxelder Bug 
Boxelder Aphid. . : 
Eastern Tent Caterpillar . 

Boxwood . : 
Boxwood Leaf Miner 

Catalpa ws 
Catalpa Sphinx — sts 
Comstock Mealybug 

Crabs and Hawthorns 
Yellow-Necked Caterpillar 
Woolly Hawthorn Aphid . 
European Red Mite 
San Jose Scale . ; 
Hawthorn Leaf Miner , 

Dogwood : 

Dogwood Borer | 
Dogwood Scale . 

Douglas Fir . . 

Cooley Spruce Gall Aphid 

Elm .. 

Spring Cankerworm . 
White-Marked Tussock Moth . 
Fall Webworm . 5 

Elm Leaf Beetle 

European Elm Scale 
Seurfy Scale . 

Putnam Scale . 

Elm Leaf Aphid 

Woolly Elm Aphid . . 
Elm Cockscomb Gall | Aphid « 
Elm Borer 


WOOAMG. RAMON IW W Oo Ww WWwWNNNrF 


Smaller European 
Elm Bark Beetle 
Banded Elm Lestloppes : 
Mites : . 
Euonymus.. . 
Euonymus Scale 
Hackberry 


Hackberry Nipple Gall | Psyllid 


Witches’-Broom 
Hickory . . 
Yellow-Necked Caterpillar 
Hickory Bark Beetle . . 
Hickory Gall Phylloxera . 
Hickory Horned Devil 
or Regal Moth . 
Juniper oe ‘ 
Juniper Scale 
Juniper Webworm . 
Juniper Bark Beetle 
Spruce Spider Mite 
Bagworm , 
Lilae : : 
Lilac Borer. cas 
Oystershell Scale 
Linden . : 
Elm Semone 
Locust 
Locust Bor er 
Bagworm 
Locust Mite 
Mimosa Webworm 
Maple : 
Cottony Maple Scale = 
Maple Bladder-Gall Mite 
Green-Striped Mapleworm . 


Flatheaded ee Tree Borer 


Aphids 
Pigeon Tremex 
Oak 
Borers : 
Periodical Cicada : 
May Beetles . 
Twig Pruner 
Oak Kermes 
Leaf Miners : 
Gall- anes Insects — 
Pine .. 
Sawflies — aude 4 
White-Pine Weevil 
Pine Needle Scale 
Pine Bark Aphid. . . 
European Pine Shoot Moth . 
Nantucket Pine Moth 
Zimmerman Pine Moth 


Poplar 
Poplar Borer 
Cottonwood Borer . . 
Poplar and Willow Borer 


Carpenterworm . % . 59 Tuliptree Aphid . 66 
Cottonwood Leaf Beetle . 60 Walnut... . 67 
Poplar Tent Maker . 60 Walnut Caterpillar 5 Of 
Oystershell Scale . . 60 Black Walnut Curculio . 68 
Privet .. . .60 Willow... on A . 68 
Privet Thrips . 60 Willow Aphid . 68 
Redbud . . 3 . 62 Bagworm . 68 
Oystershell Scale ‘ <7 « 62 Borers . , . 68 
Two-Spotted Spider Mite . . 62 Oystershell Scale . . 69 
Spirea .. ie . 62 Yew (Taxus) , . 69 
Spirea Aphid . 62 Black Vine Weevil . 69 
Spruce . . - 62 Fletcher Scale Be vial 
Spruce Spider Mite .. . 62 Termites . Spill! 
Cooley Spruce Gall Aphid . . 64 Taxus Mealybug : . 73 
Eastern Spruce Gall AU . . 64 Potential Insect Enemies 73 
Spruce Bud Scale Sod Japanese Beetle 3 
Spruce Budworm . . 65 Gypsy Moth. . 75 
Pine Needle Scale . 65 Brown-Tail Moth ~ 5 (5 
Sycamore . . . 65 About Insecticides : PG 
Sycamore Lace Bug . 65 About Spray Equipment 
Bagworm : 265 And Its Use as 
Borers . . 66 Index . 83 
Tuliptree : . 66 
Tuliptree Seale . 66 


The kodachrome for the cover and most of the photographs for this 


circular were taken by William E. Clark of the Illinois Natural History Sur- 
vey. Photographs from outside agencies are credited to those agencies. 


TO USERS OF THIS CIRCULAR 


Control measures are listed in the information sheets en- 
closed with this circular. 


Printed by Authority State of Illinois Ch. 127 IRS, Par. 58.21 


Ly 
y, 


ii 
yy, 
Ly 


oe 
DY 


Trombone-type sprayer in use. This is an inexpensive sprayer that is con- 
venient for applying chemicals to limited numbers of shrubs and small trees. 


ILLINOIS TREES AND SHRUBS: 


THEIR Insect Enemies 
Le kes ENGELS: H 


egardless of their size or cost, trees and shrubs used as orna- 

mentals may be highly prized by their owners as sources 
of shade or beauty. An important aspect of the care of orna- 
mentals is the prevention of insect damage. Such plants may be 
severely damaged or even destroyed unless their owners have at 
least an elementary knowledge of insect pests and the ways in 
which they can be controlled. To provide help in the recognition 
of insect pests of trees and shrubs used as ornamentals and to 
suggest specific measures for control of these pests is the pur- 
pose of this circular. 

Insects may damage trees and shrubs in many ways. A col- 
ony of ravenous caterpillars may strip the foliage from twigs 
and branches; hordes of aphids may suck the sap from new 
shoots and leaves, causing them to wilt or to grow abnormally; 
tiny scale insects may encrust branches and twigs, withdrawing 
enough food to kill plants outright; borers of many kinds may 
invade the bark and wood, seriously injuring or killing plants; 
more subtle but as serious is the damage caused by those insects 
that carry fungus or virus diseases. 


ABOUT INSECTS 


The first essential for effective control of insect pests is vigi- 
lance and an interest, which may be acquired, in looking for in- 
sects and signs of their damage. To detect the presence of 
insects before they cause serious damage to valuable trees and 
shrubs, one should carefully examine the plants at least once a 
week during the growing season. One should examine deciduous 
trees in winter, also, when scale insects on them may be seen 
more easily than when trees are in leaf. 

The second essential is at least an elementary knowledge of 
insects and the ways they reproduce and grow. For example, 
one should know that while most kinds of insects lay eggs, some, 
like most of the aphids, give birth to living young. The eggs of 
insects are of various sizes, shapes, and colors; most of them are 
small in size and are not easily seen. They are laid singly or in 
clusters, hidden or in conspicuous places. With few exceptions, 


2 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


insect eggs cause little or no damage, but many of the animals 
that hatch from the eggs are destructive. 

Insects develop by metamorphosis, or change. The young 
of some kinds, boxelder bugs for example, look like the adults 
and reach maturity through a series of molts. The young of 
kinds that look unlike the adults are called larvae, grubs, cater- 
pillars, or worms. Eggs deposited by moths and butterflies pro- 
duce caterpillars that feed ravenously and molt several times 
before they reach maturity. The caterpillars change to pupae 
(latent stage) for transformation to moths or butterflies. The 
growth pattern of beetles is similar to that of moths and butter- 
flies. The young of beetles are often called grubs. 

The following paragraphs contain information about sev- 
eral kinds of insects and the ways in which they feed. 

Aphids or Plant Lice.—There is a species of aphid for al- 
most every species of plant. Aphids are sucking insects, fragile 
and awkward in appearance. They are most commonly green, 
pink, or black in color. Each aphid, only one-sixteenth to one- 
eighth inch long, is well equipped with a stout beak through 
which it draws great quantities of plant juice as it feeds from 
place to place on tender plant tissue. Heavy infestations of 
aphids usually produce a noticeable amount of honeydew, on 
which a sooty mold may grow. Aphids have an enormous repro- 
ductive capacity. Fortunately they have many natural enemies. 
Lady beetles, both larvae and adults, fatten themselves on 
aphids, and the larvae of tiny parasitic wasps feed within them. 

Scale Insects.—Scale insects, small and inconspicuous, are 
likely to be overlooked until the branches of infested trees or 
shrubs are encrusted with them. They are sucking insects that 
live most of their lives under protective shells or scales. They 
may kill branches, limbs, and whole trees. Each insect is a mere 
sack of protoplasm with a threadlike beak thrust into the tissue 
of the plant it feeds upon. The female in most species of scale 
insects deposits eggs under her shell. The eggs produce crawlers 
that move away from the shell to find suitable feeding places. 
When the crawlers settle and begin to feed, each makes a shell 
for its own protection. 

Borers.—Most borers that attack trees or shrubs are the 
larvae of beetles or moths. They hatch from eggs deposited on 
the bark of a tree or shrub. Soon after hatching, they bore into 
the wood of the plant. Healthy, vigorous trees are unattractive 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 3 


to borers. Newly planted trees suffering from transplanting 
shock, and older trees growing in unfavorable places where little 
moisture or food is available, become attractive to the pests. 

Leaf Eaters.—Severe damage by this group of pests is con- 
spicuous and easy to detect. In many cases, however, damage 
is not observed until serious defoliation has occurred. The prin- 
cipal leaf eaters are beetles and their larvae (grubs) and the 
larvae (caterpillars) of moths and sawflies. Damage by these 
pests is most likely to occur in the spring and early summer. 

Mites.—Especially destructive to evergreens, these animals, 
barely visible to the naked eye, have great reproductive power 
and attack plants in large numbers. Some mites injure plants 
by rasping the leaf surfaces and removing the plant juices. 
Mites are not insects, although closely related to them. 

Gall-Producing Insects and Mites.—Galls are abnormal] 
growths appearing as warts or bumps or attractive-looking balls 
on leaves and twigs. They are of many shapes and sizes, but 
each kind is characteristic of the animal that produces it. The 
production of some galls is stimulated by tiny mites too small 
to be seen with the naked eye. The production of others is stim- 
ulated by flies, aphids, and small wasps. A part of the life cycle 
of the gall-producing animal is spent inside the gall. Most galls 
do not cause serious damage to the plants on which they are 
found. 


ABOUT TREES AND SHRUBS AND THEIR PESTS 


In the discussion that follows, the host plants are arranged 
alphabetically. Each pest and the nature of its damage are 
briefly described; notes on the life history are given for each of 
the common and destructive pests. 


AILANTHUS (TREE OF HEAVEN) 


Ailanthus Webworm, Atteva aurea (Fitch), fig. 1—An oc- 
casional pest of ailanthus, or tree of heaven, the olive-brown cat- 
erpillar of this species feeds on the leaves under a thin web. 
Sometimes it attacks the petioles, causing the leaves to wilt. 


ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


ee 


Fig. 1—Ailanthus webworm: larvae. The olive-brown larvae or worms 
feed on the surfaces of leaves. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 5 


Cynthia Moth, Samia cynthia (Drury).—The 3-inch, green 
caterpillar of this species has black dots and blue tubercles on 
its back. It feeds on the leaves of the tree of heaven. The adults 
are handsome brown moths, each with a wingspread of 6 to 8 
inches. Sometimes caterpillars of this kind defoliate the trees 
on which they feed. 


ARBORVITAE 


Bagworm, Thyridopteryx ephemeraeformis (Haw.), fig. 2. 
— A widely distributed common pest, the larva of this species 
feeds ravenously on both evergreen and deciduous trees and 


Fig. 2.— Bagworm: cases or bags constructed by larvae. Some of the 
bags shown here are almost filled with eggs laid by adult females of the 
bagworm. Eggs that survive the winter hatch in early summer. The ap- 
Remeprce of bags varies with the kinds of leaves from which the larvae have 
made them. 


shrubs. Usually evergreens defoliated by bagworms die. Some 
of the spindle-shaped bags hanging from trees and shrubs dur- 
ing the winter contain eggs that produce a crop of worms in the 
following spring or summer. In southern Illinois, these eggs 
hatch usually during the latter part of May, in central Illinois 
during the first part of June, and in northern Illinois during the 
latter part of June. Newly hatched larvae are easily overlooked. 
After leaving the mcther bag, a small larva feeds on nearby 
foliage and begins to build a tough bag for itself with silken 


6 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


thread and with bits of foliage taken from the host plant. Hence, 
bags on maples look different from those on arborvitae. 

Each bag is enlarged to accommodate the rapidly growing 
larva inside and is carried everywhere the larva goes. The larva 
sticks its head out of the bag to feed, but quickly retreats when 
disturbed by birds or other enemies. By late summer, when the 
bag is 114 to 2 inches long, the larva matures, pupates, and 
transforms to the adult stage. The adult male, a black, fuzzy 
moth, emerges from its bag and flies about to mate with the 
wingless female, which remains in the bag while she lays 500 
cr more eggs. After egg-laying, the female dies. The bagworm 
produces only one generation a year in Illinois. 

Because only the male adult flies, infestations of bagworms 
are spread principally in the larval and egg stages. Small larvae 
suspended by their silken threads may be carried by the wind 
for considerable distances. Larger larvae often crawl from one 
plant to another in search of food. Larvae or bags containing 
eggs may be inadvertently transported by human beings. 


Arborvitae Leaf Miner, Argyresthia thuiella (Pack.).— 
Feeding by the leaf-mining caterpillar of this species on the in- 
sides of needles causes the tips of arborvitae branches to turn 
whitish, tan, and brown. Less than one-fourth inch long, each 
greenish, red-tinged caterpillar comes from one of several eggs 
deposited on the leaves by a small moth in the spring. This pest 
may produce more than one generation in a season, and consid- 
erable damage may result from its feeding. 


Spruce Spider Mite.—See under Spruce. 


Juniper Scale, fig. 28.—See under Juniper. 


ASH 


Red-Headed Ash Borer, Neoclytus acuminatus (F.), fig. 3.— 
The short, white, round-headed grub of this species may girdle 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 7 


small ash trees so severely that they break and fall. The grub 
tunnels in many directions, mainly in the sapwood. The adults 
are beetles, each about one-half inch long. Each has a reddish 
head, which accounts for the common name, and a V-shaped yel- 
low band across the wing covers. The female deposits eggs in 
crevices of bark in early summer. The young larva bores through 
the bark and feeds on the sapwood. It pupates near the surface 
of the wood. In June, the pupa transforms to an adult. which 
gnaws through the wood and bark and emerges. 


Ash Borer, Podosesia syringae fraxini (Lug.), fig. 4.—This 
insect was once considered to be the same as the lilac borer, but 
it now appears to be different and to be limited to ash and moun- 


Fig. 3.—Red-headed ash borer: A, adults; B, larva or grub; C, adult 
ready to emerge from its pupal case; D, furrows made by larvae in sapwood 
and holes through which adults emerged. 


8 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 4.—Ash borer: adult (museum specimen). The female adult, a 
clear-winged moth, deposits eggs on the bark of a tree. Upon hatching, the 
young borers penetrate the bark and bore into the wood. 


tain ash. The adult, a moth with transparent rear wings, depos- 
its eggs on the bark of the tree. The white larva eats through 
the bark, penetrating the harder wood to the center of some 
branches. In the fall, when nearly full grown, and almost an inch 
long, the borer works toward but not completely through the 
bark. Here it digs a sort of cell in which it passes the winter. 
Pupation occurs in the spring, and moths emerge in May and 
June. 


Oystershell Seale, Lepidosaphes ulmi (L.), fig. 5.—The oys- 
tershell scale is inconspicuous, but it can be detected by careful 
examination of the limbs and branches it infests. Each scale 
protects itself by a light to dark brown oystershell-shaped cov- 
ering about one-eighth inch long. It feeds by sucking plant sap 
through a threadlike beak. Dense populations of this insect 
cause severe damage to many kinds of trees and shrubs. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 9 


Fig. 5.—Oystershell scale: an infestation on a twig. A sapsucking in- 
sect is beneath each brownish shell. An infestation of this common and 
destructive insect may kill twigs and branches of lilac and other plants. 


The overwintering, pearly white eggs of the oystershell 
scale hatch about the latter part of May, the time varying with 
weather and latitude. Each young scale, called a crawler, moves 
from beneath the mother shell and crawls about, usually toward 
younger wood. After a short time the crawler settles, loses its 
legs and antennae, and starts making a shell covering. The cov- 
ering is enlarged from time to time to accommodate the grow- 
ing insect. The male scale develops wings, escapes from the 
shell by squeezing under the edge, and roams freely for a mate. 
The female does not leave her shell for the mating event, but 
keeps sucking away at the tree sap. Under her shell she lays 
80 to 100 eggs, which hatch the following spring. 


Fall Webworm, Hyphantria cunea (Drury), fig. 6.—Un- 
sightly webs enclosing one or more branches of an ash in the 
early fall are signs of a ravenous colony of hairy caterpillars of 
the kind commonly known as the fall webworm. The adult fe- 
male of the fall webworm, a satiny white moth, emerges from 
one of the overwintering cocoons in early summer, mates, flies 
into a suitable tree, and deposits a patch of several hundred 
greenish eggs, usually on the under side of a leaf. On hatching, 
the young caterpillars move as a group to the upper sides of 
leaves and start feeding. At the same time, they start spinning 


10 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


a web, which they enlarge to take in fresh foliage as needed. 
They do not consume the leaves entirely but skeletonize them to 
such an extent that they curl, dry up, and eventually die. 


Fig. 6.—Fall webworm: tent and damage. The tent or webbing contains 


a colony of pale green, or yellow, hairy caterpillars that feed on foliage of 
the host tree. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 11 


Pale green or yellow in color, each with a dark stripe down 
the back and a yellow stripe along each side, the caterpillars do 
not leave the web until nearly full grown. At this time they 
move in many directions and feed on almost any green foliage 
available. When mature, they move to the ground to pupate 
under sheltering debris or just below the surface of the soil. 


BIRCH 


Bronze Birch Borer, Agrilus anzius Gory.—Widely distrib- 
uted and a serious pest of birch trees in the open, especially 
white birch, the three-fourths-inch long, white, flattened, and 
footless grub of this species attacks all parts of the birch above 
ground, burrowing under the bark and causing the bark to 
loosen and separate from the wood. The slender bronze beetle 
that develops from an overwintering grub cuts semicircular 
holes through the bark and emerges in early spring. The female 
lays white eggs in bark crevices. Larvae hatching from the eggs 
penetrate the bark, feed, and grow to develop another genera- 
tion. 


Birch Skeletonizer, Bucculatrix canadensisella Chamb.— 
Unlike the bronze birch borer, which prefers trees in the open, 
the larva of this insect prefers woodland trees for its periodic 
attacks. Tiny caterpillars hatch from eggs placed singly on a 
leaf by the very small female moth, which is seldom seen. Each 
caterpillar bores directly into the leaf tissue, mines the leaf for 
a few weeks, and then skeletonizes the leaf on the under side be- 
fore dropping to the ground to pupate for the winter. The most 
extensive damage by this insect is likely to occur in August. 


BOXELDER 


Boxelder Bug, Leptocoris trivittatus (Say), fig. 7.—The 
adult form of this species is a black and red bug that feeds 
through a long, slender beak on the leaves and seed pods of the 
boxelder tree. It does little damage to the tree, but it creates a 
nuisance by congregating in great numbers about the tree and 
by migrating to nearby dwellings in the fall in search of winter 


12 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fie. 7—Boxelder bug: adults. Shown here are boxelder bugs on the 
foundation of a building. The bugs, which are black and red in color, are of 
no consequence as pests of boxelder trees, but they are nuisances in and on 
buildings. 


quarters. Fcllowing hibernation, the female lays small, red eggs 
in bark crevices. The red-bodied, black-legged nymphs that 
hatch from the eggs reach the adult stage through a series of 
molts. 


Boxelder Aphid, Periphyllus negundinis (Thos.).—This is a 
pale green, hairy plant louse that occasionally develops in great 
numbers. An infestation by this aphid causes some injury to 
the infested tree and creates a nuisance by covering sidewalks 
and other objects beneath the tree with honeydew. Black eggs 
are deposited by the female on branches in the fall. The eggs 
hatch in the spring, and young aphids congregate on the new 
buds, from which they withdraw plant juices through their slen- 
der beaks. With the ability to develop several generations within 
a few weeks, these aphids can soon become abundant. 


Eastern Tent Caterpillar, Malacosoma americanum (F.), 
fig. 8.—Although black cherry, chokecherry, and apple are 
favorite hosts, ravenous caterpillars of this species in the 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 13 


Fig. 8.—Eastern tent caterpillar: larvae and damage to boxelder foliage. 
The female adult, a moth, lays a batch of eggs on a twig to produce a col- 
ony of hairy caterpillars with black heads. 


14 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


spring construct tents in a wide variety of trees, including box- 
elder, elms, maples, and oaks. The black, hairy caterpillars 
hatch in March from an overwintering mass of eggs plastered 
to a twig in a brown band or collar. Caterpillars usually select a 
fork of a branch for the construction of a tent. They leave the 
tent to feed during the day but return at night. After feeding 
for 5 or 6 weeks, each caterpillar spins a cocoon on a tree trunk 
or in some other protected place, where it pupates. The adults, 
reddish-brown moths, emerge in early summer. This insect pro- 
duces only one generation a year. It occurs in abundance at in- 
tervals of about 10 years. 


BOXWOOD 


Boxwood Leaf Miner, Monarthropalpus buxi (Lab.).—Dam- 
age by this insect is indicated in early summer by small blotches 
on the leaves of boxwood. Later the blotches enlarge to blisters 
that cause the leaves to turn brown and to drop. The small yel- 
lowish-green maggots or larvae of this species feed on the tissue 
in the leaf during the summer and again in the spring before the 
orange-yellow midges develop and emerge from the pupae. The 
female deposits eggs in May for a new generation. 


CATALPA 


Catalpa Sphinx, Ceratomia catalpae (Bdv.), fig. 9—A rav- 
enous feeder consuming great quantities of catalpa foliage, the 
caterpillar of the sphinx moth may vary in color from pale yel- 
low with green markings to almost black. The caterpillar has 
a black, hornlike process at its rear end. When grown, the cater- 
pillar is about 3 inches long. 

Emerging from an overwintering pupa in the soil, the fe- 
male of this moth mates and lays hundreds of eggs in white 
masses on the under sides of leaves. The young caterpillars 
feed in groups at first, but work individually later, consuming 
entire leaves. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 


Fig. 9.—Catalpa sphinx: larvae on a catalpa leaf. The handsome cater- 
pillars are ravenous feeders on catalpa foliage. About 3 inches long when 
grown, each caterpillar has a black hornlike process at the rear end. 


16 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Comstock Mealybug, Pseudococcus comstocki (Kuw.).—An 
occasional pest of catalpa, the Comstock mealybug is likely to be 
found in cottony masses at the forks of tender shoots or at the 
bases of leaves. The male, which has wings, is seldom seen. The 
female, a wingless, slow-moving insect, when grown is about 
one-fourth inch long and elliptical in shape; she has a fringe of 
short, soft spines and is covered with ‘‘mealy,” white wax. A 
sucking insect like the aphid, the mealybug likewise secretes 
honeydew, which supports a sooty mold. 

The mealybug’s yellow eggs, found in crevices of bark, are 
covered with a cottony mass of wax. When leaves appear on 
catalpa trees in spring, the eggs hatch, and the young mealy- 
bugs move to likely placés to feed and grow. This insect may 
produce several generations a year. 


CRABS AND HAWTHORNS 


Yellow-Necked Caterpillar, Datana ministra (Drury), fig. 
10.—While seeming to prefer the foliage of apple and other fruit 
trees, the larva of this species finds nothing distasteful about 
the foliage of ornamental crabs and hawthorns wherever these 
plants are grown. Reddish in color when young, the ugly, fuzzy 
caterpillar has a yellow neck. It has a black head and four yel- 
low stripes along each side of its body. Caterpillars of this spe- 
cies feed ravenously in groups, but, when disturbed, they stop 
feeding and rear up at both ends. When fully grown, each cat- 
erpillar drops to the ground, burrows in a short way, and pu- 
pates. The adults, or moths, appear in early summer, and at 
about this time the female deposits eggs in clusters on the 
under sides of leaves. 


Woolly Hawthorn Aphid, E'riosoma crataegi (Oest.), fig. 11. 
—Occurring in dense colonies on twigs and branches, the white, 
restless plant lice of this species are conspicuous. They may 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 


ae ae 
©» : bo he Ny 
cw 


yen 


Fig. 10.—Yellow-necked caterpillar: larvae on small branch of haw- 
thorn. When disturbed, these caterpillars rear up at both ends. Reddish 
when young, each caterpillar has a black head and four yellow stripes along 
each side of its body. A grown caterpillar is easily recognized by its yellow 
neck and its black body, which is covered with long, white hairs. 


‘Fig, 11.—Woolly hawthorn aphid: infestation on hawthorn twig. The 
aphids, which are white in color, have sucking mouthparts. 


18 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


cause considerable damage to the hawthorn, distorting leaves 
and shoots by their removal of plant juices. The life history of 
this aphid is probably a complicated one and is not well known. 


European Red Mite, Panonychus ulmi (Koch) .—Leaves of 
hawthorn or crab lacking a glossy, green appearance and hav- 
ing a somewhat blanched, or brown, dry look and a tendency to 
curl are signs of damage produced by hundreds of tiny red mites 
of this species feeding on both leaf surfaces. Brick red in color, 
the adults of the European red mite are scarcely the size of pin- 
heads. They have bristle-like hairs curving backward over their 
robust, globular bodies. The female deposits her eggs, which 
look like tiny cherries, in great numbers on both leaf surfaces. 
Development of the mite occurs through a series of molts. The 
white, discarded molt skins of a great number of young mites 
make infestations conspicuous. Rasping of the leaf surfaces 
and withdrawal of chlorophyll and plant juices cause serious 
damage to the plants infested. 


San Jose Scale, Aspidiotus perniciosus Comst., fig. 12.— 
Probably the best known of the scale insects, San Jose scale is 
widely distributed and is a serious pest on many trees and 
shrubs. Heavy infestations encrust limbs and branches, causing 
them to die. Scraping an infested branch with a thumbnail or a 
knife squeezes the yellow juice from the saclike insects beneath 
the gray to black, circular shells, each about one-sixteenth inch 


Fig. 12.—San Jose scale: infestation on bark of tree. A yellow saclike 
insect is beneath each circular shell shown here. The shells are each about 
one-sixteenth inch in diameter and gray to black in color. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 19 


in diameter. The female overwinters as a partly grown insect 
and reaches maturity in early spring. After mating, she gives 
birth to living young: small, flat, yellow creatures, which crawl 
out from under the mother shell. When a crawler finds a suitable 
place, it settles down, inserts its threadlike beak into the bark 
tissue, loses its legs and antennae, and starts making a shell for 
its own protection. As the scale grows, its shell is enlarged and, 
following a series of molts, the scale reaches maturity. The 
fragile male scale develops wings and escapes from its protective 
shell to mate with a female, which does not leave its shell. The 
San Jose scale may produce several generations in a summer. 


Fig. 13. — Hawthorn leaf miner: larva and damage to hawthorn leaf. 
The upper epidermis along one margin of the leaf is folded back to dis- 
close the white larva (arrow) and its excrement. Along the opposite mar- 
gin of the leaf is a dark blister, a sign of damage by the leaf miner. 


20 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Hawthorn Leaf Miner, Profenusa canadensis (Marlatt), fig. 
13.—Conspicuous dead areas that may include a fourth to half of 
a leaf at the tip or side indicate damage by the leaf miner. The 
adult is a sawfly, a beelike insect, that emerges from an over- 
wintering pupal case in the soil and deposits eggs in the tissue of 
unfolding leaves in May. The eggs, which may number 1 to 5 per 
leaf, produce larvae that mine the leaves. About 2 weeks after 
hatching, each larva makes a hole in the leaf and drops to the 
ground, where pupation and hibernation occur. This insect pro- 
duces one generation a year. 


DOGWOOD 


Dogwood Borer, Thamnosphecia scitula (Harr.).—The cat- 
erpillar of this species is white and it has a brown head. It is the 
larva of a clear-winged moth with a wingspread of less than an 
inch. Eggs deposited by the female moth on the bark of dogwood 
trees in May and June produce borers that eat through the bark. 
These borers feed just beneath the bark, often girdling limbs 
and small trees. The borers become full grown before winter, 
hibernate in their tunnels, and change to pupae in the spring. 


Dogwood Scale, Chionaspis corni Cooley.—Usually kept un- 
der control by natural enemies, this scale occasionally builds up 
dense populations that give twigs and branches a whitish appear- 
ance. The female scale is somewhat pear shaped and about one- 
eighth inch long; the male scale is smaller and more slender and 
has three ridges on the upper side. Purple eggs carry the insect 
through the winter. 


DOUGLAS FIR 


Cooley Spruce Gall Aphid, Chermes cooleyi Gill., fig. 14.— 
Douglas fir is the intermediate host for this small aphid, which 
splotches the needles with cottony masses of wax that protect 
the aphid and her eggs. Some of the aphids developing from 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 21 


Fig. 14.—Cooley spruce gall aphid: an infestation on Douglas fir. Each 
white splotch on the needles represents a cottony mass of wax that protects 
an aphid. Beneath the wax the female lays her eggs. Some of the insects 
developing from these eggs have wings; others do not. Those that have 
wings migrate to spruce, where they produce galls at the tips of branches. 


these eggs have wings and they migrate to spruce, where they 
produce galls. No galls develop on Douglas fir. 


ELM 


Spring Cankerworm, Paleacrita vernata (Peck), fig. 15 and 
16.—The spring cankerworm is a common pest of elms and per- 
havs the most important leaf eater that infests the American 
elm in Illinois. The caterpillar, or larva, is a dark green or black 
“measuring worm” that does not wait for the buds to unfold be- 
fore starting to feed. At first rather inconspicuous, the small 
caterpillar eats the tissue on one side of any leaf it feeds upon, 
but as it grows it punctures and later consumes all of the leaf 
except the large veins. By the time the caterpillar is 1 inch long, 
or full grown, it may be red, green, yellow, or black in color. 
It drops to the ground by means of a thread, burrows into the 
soil, and pupates. The adults emerge during warm spells in late 


22 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


winter. The wingless female climbs a nearby tree and, after mat- 
ing, hides hundreds of eggs in crevices and under loose bark. 
These eggs hatch just as soon as the leaf buds begin to open in 
the spring. An elm may be partly or completely stripped of its 
foliage by spring cankerworms. 


Fig. 15.—Elm foliage damaged by spring cankerworms. The dark green 


to black “measuring worms” begin feeding before leaf buds are completely 
open. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 23 


White-Marked Tussock Moth, Hemerocampa leucostigma 
(J. E. Smith), fig. 17—Second in importance to the spring can- 
kerworm as a leaf eater of American elm, this insect in its larval 
stage is mainly a pest of city shade trees. The showy caterpillar 
of the tussock moth begins feeding a little later in the spring 
than the cankerworm but may develop two generations in a 
year to make up for the late start. Its body is covered with tufts 


Fig. 16.—Spring cankerworm: A, male adult; B, female adults (wing- 
less); C, eggs; D, larva; E, pupae. The larva is dark green, brown, or 
black. (Photographs from United States Department of Agriculture.) 


of long white hairs. Two longer tufts of black hairs provide 
“horns” at the front, while a single black tuft “flags” the rear. 
When 5 or 6 weeks old, the caterpillar stops consuming leaves 
and spins a cocoon on the trunk or a limb of the tree on which it 
has been feeding, or on a fence or house. Here transformation 
takes place. From the cocoons emerge winged males and wing- 
less females. A wingless female, after emerging and mating, 
lays several hundred white eggs, all glued together in a clump, 


24 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 17.—White-marked tussock moth: caterpillar, or larva, on leaf. 
This caterpillar is hairy; it has a red head, and its body is strikingly colored 
with yellow, black, red, and white. 


on the empty cocoon. Newly hatched caterpillars skeletonize the 
leaves and consume all but the large veins. 


Fall Webworm, fig. 6.—See under Ash. 


Elm Leaf Beetle, Galerucella luteola (Miiller), fig. 18.—An- 
other ravenous leaf eater and a particular pest of Chinese elm, 
the larva or grub of the elm leaf beetle skeletonizes the leaves, 
causing them to dry out, curl, and drop prematurely. An ugly, 
almost black, spiny grub hatches from each of the yellow, 
spindle-shaped eggs placed by the female beetle in small groups 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES ES) 


Fig. 18.—Elm leaf beetle: A, eggs; B, larva; C, pupa; D, adult. Both 
larva and adult feed on foliage. The eggs are yellow and spindle shaped; the 
larva is spiny and almost black; the adult, about one-fourth inch long, has 
a yellowish to green body and yellowish legs and antennae. 


on the under sides of the leaves of an elm tree about the time 
the leaves become full grown. When through feeding, the grub 
drops or crawls to the ground near the base of the tree, pupates, 
and transforms to the adult stage to start another generation. 
The adults hibernate in barns, sheds, and dwellings, where, if 
present in large numbers, they sometimes become a nuisance. 
Each beetle is about one-fourth inch long; it has yellow legs 
and antennae and a yellowish to green body. It chews small holes 
in the foliage. The female beetle lays 400 to 800 eggs, which 
hatch in about a week. 


European Elm Scale, Gossyparia spuria (Mod.), fig. 19.— 
Although inconspicuous, like other scale insects, the European 
elm scale occurs in dense populations and sucks great quantities 
of sap from any tree it infests. Some of the sap is secreted as 
honeydew, on which a sooty mold may grow. 

The immature scale, which overwinters on a limb or branch 
or in a crotch of an elm, is about one-tenth inch long, oval, red- 
dish-brown in color, and has a white fringe. The male completes 
development in a white cocoon. The female changes little from 
the overwintering form. In early summer, she lays eggs on a 
limb or branch. Hatching in an hour or so, the young scales 
move in great numbers to the under sides of nearby leaves, 


26 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 19.—Eurcpean elm scale: an infestation on an elm twig in spring. 
Fach scale has a reddish center and a white fringe. 


where they settle and feed until late summer. Many migrate 
back to a limb or branch to hibernate, but some are lost when 
the leaves drop in autumn. 


Scurfy Scale, Chionaspis furfura (Fitch), fig. 20.—Widely 
distributed and a pest of fruit and shade trees in addition to elm, 
the dirty white, pear-shaped scale of this species is about one- 
eighth inch long. Infestations of this scale are more conspicuous 
than the infestations of some other scales, especially when they 
are dense enough to give the infested bark an ugly appearance. 
Withdrawal of sap from a tree by an infestation of this scale 
reduces the vitality of the tree, kills branches and limbs, and 
sometimes, if the tree is young, deforms it. 

The purple eggs, which carry the insect through the winter, 
begin hatching toward the last of May, giving rise to tiny purple 
crawlers that move away from the mother’s shell. The crawlers 
soon settle on the bark to feed and to make shells of their own. 
The scale covering of the female is broad, while that of the male 
is narrow and has three longitudinal ridges. This scale may 
produce two generations a year in the southern half of Illinois, 
but usually it produces only one generation a year in the northern 
half of the state. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 


Fig. 20.—Scurfy scale: an infestation on an elm twig. The scales are 
gray and somewhat pear shaped. The overwintering eggs under the shells 
are purplish. The hole made in one scale by an emerging parasite is indi- 
cated by an arrow. 


Fig. 21.—Putnam scale: an infestation on an elm twig. The covering 
or shell of the female scale is almost circular and about one-sixteenth inch 
in diameter; that of the male is oblong. Near the center of each shell is a 
brick-red nipple that contrasts with the dark gray or black remainder of 
the shell. The scale insect beneath the shell is yellow. 


28 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Putnam Scale, Aspidiotus ancylus (Putn.), fig. 21.  Put- 
nam scale sometimes encrusts limbs and branches, causing them 
to die. Only about one-sixteenth inch in diameter, the female 
scale covering is almost circular and is cemented to the bark 
as a shell resembling an inverted saucer with a brick-red nipple 
that contrasts with the dark gray or black remainder of the shell. 
The shell of the male of the Putnam scale is oblong in shape. 


Fig. 22.—Elm leaf aphid: infestation on under side of elm leaf. The 
aphids are greenish and of various sizes; some have wings ard some are 
wing less. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 29 


The insect passes the winter as a yellow, partly grown scale 
beneath the shell. Development is completed in early spring, and, 
after mating, the female lays a few eggs a day. Egg laying and 
hatching extend over a period of 6 weeks or more. Some of the 
first-brood crawlers settle on the leaves of the elm, where de- 
velopment is completed; the second brood crawlers migrate back 
to the limbs or branches for the winter. 


Elm Leaf Aphid, Myzocallis ulmifolt (Monell), fig. 22.— 
For the most part, this aphid is a nuisance pest because of the 
honeydew that drips on sidewalks and automobiles from the elm 
leaves on which the aphid feeds. Except for sooty mold that 
grows in the honeydew, there is no visible evidence of damage. 

Both winged and wingless forms of the yellowish-green 
aphid, as well as white molt skins, are usually present on the 
under sides of elm leaves. Unlike many species of aphids, the elm 
leaf aphid does not migrate to another host. 


Woolly Elm Aphid, E'riosoma americanum (Riley).—Curled 
elm leaves are signs of an infestation on the under sides of the 
leaves by the white, woolly, restless aphids of this species. In- 
festations are localized rather than general. This species over- 
winters in the egg stage. Eggs laid on bark hatch about the 
time elm leaves unfold; upon hatching, the aphids crawl to the 
leaves and begin to suck juices from the tissues. In June, the 
winged form migrates to shadbush, where it gives birth to a 
wingless form which, in time, produces another winged form 
that migrates back to elm to lay the overwintering eggs. 


Elm Cockscomb Gall Aphid, Colopha ulmicola (Fitch), fig. 
23.—On an elm leaf, a conspicuous, unsightly growth resembling 
a cock’s comb is a sign of this aphid. Production of each gall is 
stimulated by a wingless female aphid. 


Galls produced by aphids of this species do little 

damage. No control measure is recommended. 
Elm Borer, Saperda tridentata Oliv., fig. 24.—Escaping sap 
and small masses of wet, brown frass on the trunks and limbs of 


30 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 23.—Elm cockscomb galls. Each gall contains many greenish aphids. 


elms indicate the presence of larvae of this species. Probing an 
infested tree with a knife will disclose flat, shallow galleries run- 
ning in many directions and white, legless, segmented grubs. 
Each larva is about an inch long when full grown. The larva pu- 
pates in May. The adult is a gray beetle, about one-half inch 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 31 


long, with three orange-colored stripes across each wing cover. 
The beetle cuts through the bark to escape. After mating, the 
female beetle deposits eggs on the bark of an elm tree. The 
young grubs that hatch from the eggs bore into the bark. 


Smaller European Elm Bark Beetle, Scolytus multistriatus 
(Marsh.), fig. 25.—This bark beetle is the more important of two 


Fig. 24.—Elm borer: A, larva; B, pupa; C, adult. The larva, or grub, 
is white and legless. The adult is a gray beetle about one-half inch long 
that has three orange-colored stripes on each wing cover (stripes only 
faintly visible in picture). 


species that spread the deadly Dutch elm disease in Illinois. The 
other is the native elm bark beetle, Hylurgopinus rufipes 
(Eichh.), which is rarely found in Illinois. 

The white, legless grub, or larva, of this beetle passes the 
winter under the bark of an elm tree. It pupates in early spring 
and transforms to the adult, a reddish-brown beetle, which drills 
a small hole through the bark to escape. Thousands of “shot 
holes” characterize the bark of heavily infested trees. If the 
beetle emerges from a tree infected with Dutch elm disease, it 
may carry spores of the disease fungus to a healthy tree, where 
inoculation takes place when the beetle feeds in the crotches of 
small branches. After feeding in the crotches of living elms, the 
beetle bores into recently cut elm wood or weak and dying tree 
trunks or branches. The female places white, spherical eggs 
along the edges of a gallery she constructs for this purpose. 
Small, white larvae that hatch from the eggs feed between the 
bark and wood, producing characteristic patterns with their 


ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 25.—Smaller European elm bark beetle: larvae and galleries on the 
under side of elm bark. The adults, small, brown beetles, carry the Dutch 
elm disease fungus from diseased to healthy elms. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 33 


mines. Emergence of beetles begins about the middle of May in 
Illinois and reaches a peak about the middle of June. A second 
brood of beetles which follows reaches a peak emergence in 
August. 


Banded Elm Leafhopper, Scaphoideus luteolus Van D.— 
Rarely seen, this brown leafhopper, narrow and about one-fourth 
inch long, is reported to be the carrier of phloem necrosis, a seri- 
ous virus disease of American elms. The eggs of this insect over- 
winter on the bark of elms and hatch in early spring; the young 
hoppers, called nymphs, feed on new foliage, producing a brown 
area where the sap is withdrawn. The leafhoppers themselves 
cause little direct damage, but the virus they carry from diseased 
to healthy American elms is deadly to the trees. 


Mites.—Several species of mites infest elms, but usually the 
damage they do is of little consequence. However, following the 
repeated use of certain insecticides on elm foliage, infestations 
of the two-spotted spider mite, Tetranychus telarius (L.), may 
become dense enough to bronze the leaves by their feeding and 
reduce the vitality of trees. 


EVONYMUS 


Euonymus Scale, Unaspis euonymi (Comst.), fig. 26.—This 
most important and destructive pest of euonymus is common 
also on bittersweet and pachysandra. The great number of white 
coverings of the males on the under sides of the leaves of in- 
fested plants immediately attracts attention and serves to help 
identify the pest. The female lives under a gray or brown shell, 
shaped somewhat like the shell of an oyster. In spring, the over- 
wintering female lays orange-yellow eggs, which produce 
crawlers that leave the mother shell and find a place to settle and 
grow on the host plant. This scale produces at least two genera- 
tions a year. 


ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 26.—Euonymus scale: infestations on leaf, A, and twigs, B and Cc, 
of euonymus. Most of the scales shown are males, each of which has a white 
covering. The dark scales on twig B are females. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 35 


HACKBERRY 


Hackberry Nipple Gall Psyllid, Pachypsylla celtidismamma 


(Riley) .— Conspicuous growths on the under sides of hackberry 


leaves are signs of an infestation of this insect, sometimes called 


a 


Roe A Ye r) 
Pe Nie 


-brooms on a hackberry tree. The brooms are very 


Fig. 27.—Witches’ 
when no leaves are on the tree. 


conspicuous in winter, 


36 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


a jumping plant louse. Formation of each gall is stimulated by 
a tiny insect that feeds and lives inside the gall. The small, yel- 
lowish-brown adults pass the winter in bark crevices of trees or 
in the debris under trees. About the time leaf buds unfold, the 
female deposits eggs on the under sides of leaves. When the 
eggs hatch, each young insect crawls to the upper side of a leaf, 
settles down, and begins to feed through a short beak. The leaf 
tissue grows around the insect in characteristic fashion to form 
a gall. By September the insect completes its development and 
emerges as an adult through a slit it makes in the base of the 
gall. At that time of vear, insects of this species may make 
nuisances of themselves by flying into houses. 


Witches’- Broom, fig. 27.—Abnormal growth that results in 
bunches or tufts of small twigs on the limbs and branches of 
hackberry is commonly called witches’-broom. Apparently the 
brooms do little harm to an affected tree, but they detract from 
its appearance. A tiny mite, Aceria snetsingeri Keifer, and a 
fungus, Sphaerotheca phyloptophila Kell. & Swingle, are asso- 
ciated with witches’-broom, but it is not known whether either 
or both stimulate the peculiar growth. 

No control for witches’-broom on hackberry has 
been developed. 


HICKORY 


Yellow-Necked Caterpillar, fig. 10.—See under Crabs and 
Hawthorns. 

Hickory Bark Beetle, Scolytus quadrispinosus Say.—Small 
emergence holes in the bark of the trunk and branches of a hick- 
ory tree are signs of an infestation by this species. The adults 
are dark brown beetles, each less than one-fourth inch long. 
After emerging from beneath the bark, each beetle feeds for a 
short time on young twigs, then bores through the bark of the 
same or a different tree, and constructs a gallery between the 
bark and the wood. Along the edges of the gallery, the female 
deposits eggs that give rise to white, legless grubs, which cause 
further and more extensive damage. 

This species is especially injurious to 
hickories growing in parks. Heavily infested trees should be 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 37 


cut down during the winter to destroy overwintering grubs. 
Healthy trees should be kept in a vigorous condition with appli- 
cations of water and fertilizer. 

Hickory Gali Phylloxera, Phylloxera caryaccaulis Fitch.— 
Often overlooked until the affected twigs have died and the 
globular galls have been abandoned and have turned black, the 
greenish insects of this species may cause considerable or little 
injury to hickories, depending on the degree of infestation. 
After hatching from overwintering eggs, the young aphids 
stimulate the growth of galls on new twigs and prevent normal 
growth or kill the twigs beyond the galls. Each gall, which is at 
first green and may be one-half to three-fourths inch in di- 
ameter, is crowded on the inside with the greenish plant lice. 


Hickory Horned Devil or Regal Moth, Citheronia regalis 
(F.).—The larval form of this insect is an occasional leaf eater 
of hickory as well as several other trees. It looks enough like the 
devil to be frightening. Approximately 5 inches long, this larg- 
est of our native caterpillars has a green body, a red head, and 
curving red horns just back of the head. In contrast, the adult 
insects are beautiful olive-green moths with a wing expanse of 
4 to 6 inches. 

Although a ravenous feeder, the hickory 
horned devil does not occur in sufficient numbers to justify spray- 
ing. Caterpillars on small trees can be collected and destroyed 
by hand. 


JUNIPER 


Juniper Scale, Diaspis carueli Targ., fig. 28.—This pest is 
common on various kinds of junipers, especially on plants used 
for landscaping. The covering of the female scale is nearly cir- 
cular and is dirty white in color. The covering of the male scale 
is white; it has a median ridge and is narrower and smaller than 
that of the female. Juniper scale may develop into a dense popu- 
lation on twigs and branches of junipers, causing them, or even 
entire plants, to die. In May, the overwintering female deposits 
eggs, which hatch in June. 


38 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Juniper Webworm, Dichomeris marginella (F.), fig. 29.— 
The larva of this species is a light brown caterpillar only about 
one-half inch long. Several caterpillars web together and feed on 
juniper foliage, causing it to turn brown and die. Development 
of the caterpillars is completed in early summer. Pupation occurs 


Fig. 28.—Juniper scale: an infestation on juniper. Dark red, sapsucking 
scale insects are under the gray or white shells on the surfaces of twigs. 


in the webbing and debris; from each pupa a moth emerges. The 
female deposits eggs on foliage to produce another brood of cat- 
erpillars that pass through the winter. The caterpillars become 
active again in the spring. 


Juniper Bark Beetle, Phloeosinus dentatus Say.—Several 
kinds of junipers are damaged by the adults of this species, dark 
brown, tubular beetles, each about one-sixteenth inch long. Be- 
ginning in early spring, the beetles feed in the crotches of small 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 39 


branches, weakening many of them so that they bend down, 
break, and die. 


Spruce Spider Mite.—See under Spruce. 


Bagworm, fig. 2.—See under Arborvitae. 


Fig. 29.—Juniper webworm: larva (inset) and web on damaged branch. 
A colony of the small, brown caterpillars of this insect usually kills an.in- 
fested branch. 


40 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


LILAC 


Lilac Borer, Podosesia syringae syringae (Harr.), fig. 30.— 
The larva of this insect is a major pest of lilac. The adults are 
moths that have transparent rear wings. Holes made in the bark 
of lilac by the grubs are likely to be numerous and are charac- 
terized by protruding sawdust, oozing sap, and, in the spring, by 
brown pupal cases at the entrances of emergence holes. Eggs 
deposited by the female in early summer on rough bark give rise 
to the white grubs that bore through the bark into the wood be- 
neath, where they feed and grow until winter brings their activi- 
ties to a halt. 


Oystershell Scale, fig. 5—This is a major pest of lilac. See 
under Ash. 


LINDEN 


Elm Spanworm, Ennomos subsignarius (Hbn.).—The adult 
form of this species is sometimes called the snow-white linden 
moth. Both male and female are pure white. The larva or cater- 
pillar is a gray and brown looper with irregular yellow marks. 
Outbreaks of this insect occur at intervals of 10 to 20 years. The 
female moth deposits eggs in the summer on tree branches. The 
eggs do not hatch until the next spring. When outbreaks occur, 
the caterpillars are present in such numbers that they defoliate 
linden and several other kinds of trees. 


LOCUST 


Locust Borer, Megacyllene robiniae (Forst.).—Black locust 
is particularly susceptible to the larva of this insect. The larva 
is white, cylindrical, and up to 1 inch long. At first it mines 
the bark and sapwood of the locust, but later it bores into the 
heart of the tree, often causing so much damage that the trunk 
breaks. Growth, pupation, and transformation of the insect take 
place in the wood. The adults are beetles that emerge in autumn 
and feed on the pollen of goldenrod. Each is about three-fourths 
inch long, black, and has zig-zag yellow lines across the back. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 41 


Fig. 30.—Lilac borer: A, damage to lilac branch; B, adult, a clear- 


winged moth, on twig with frass at exit holes; C, larva in lilac branch (cross 
section). (Photographs A and B from Connecticut Agricultural Experi- 


ment Station.) 


42 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


ke See 


Fig. 31.—Mimosa webworm: A, honey locust twig infested with mimosa 
webworm; B, “nest” in which the mimosa webworm larvae feed; C, mimosa 
webworm larva and honey locust leaflets. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 43 


The female deposits eggs in the cracks and crevices of locust 
bark. 


Bagworn, fig. 2.—This pest occurs on both black locust and 
honey locust. See under Arborvitae. 


Locust Mite, Hotetranychus multidigituli (Ewing).— This 
mite, somewhat similar to other species of mites found on trees 
and shrubs, seems to be peculiar to honey locust. Just large 
enough to be visible to the naked eye, the mite varies in color 
from pale yellow to green; it has irregular dark areas near the 
edge of the body. The female deposits colorless spheroid eggs 
along the midrib of the under side of a leaflet. The base of the 
leaflet on the under side is the preferred feeding area. At first, 
heavily infested foliage appears stippled from above, but later it 
becomes blanched, and leaflets drop prematurely. 


Mimosa Webworm, Homadaula anisocentra Meyrick, fig. 31. 


The adults, mouse-gray moths, each with a wing expanse of 
only about one-half inch, emerge from overwintering pupae early 
in June. The female deposits eggs on the leaves of honey locust 
or mimosa. The small, pale gray to brown larvae web the leaves 
together to form a sort of nest, in which they skeletonize the 
leaflets. Badly damaged leaflets become dry and brown. In Illi- 
nois, such symptoms of webworm attack may appear by the 
latter part of July. When grown, each larva drops to the ground 
on a silken thread to pupate under ground cover. Second brood 
larvae produce conspicuous webbing in August. In the Wash- 
ington, D. C., area, the mimosa webworm produces a partial third 
generation each year. 


MAPLE 


Cottony Maple Scale, Pulvinaria’ innumerabilis (Rathv.), 
fig. 32.—A common, conspicuous, and injurious pest of soft ma- 


44 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


ple, this species is found on several kinds of maples and a variety 
of other trees and shrubs. The infestations may be heavy enough 
to kill twigs, branches, limbs, and, occasionally, entire trees. 
The scale insects secrete great quantities of honeydew that drips 


Fig. 32.—Cottony maple scale: infestation on soft maple. An infesta- 
tion of this insect can be identified easily by the masses of white wax, each 
of which contains hundreds of eggs. 


on branches and foliage of infested trees, and on sidewalks and 
automobiles below. A sooty mold that sometimes grows in the 
honeydew causes branches and foliage to appear black. 

The partly grown, brown, oval, female scale overwinters on 
a twig or branch. She grows rapidly in the spring and lays hun- 
dreds of eggs in a mass of cottony threads. Heavily infested 
branches appear as if decorated with popcorn. When the eggs 
hatch in June or July, young scales migrate to the leaves, where 
they settle and suck food from the leaf tissue. The males and 
females become mature in August; after mating, each female 
crawls back to a twig for the winter. 


Fortunately, cottony maple scale has many natural enemies 
which help control it. However, at times sprays may be needed. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 45 


Maple Bladder-Gall Mite, Vasates quadripedes (Shimer), fig. 
33.—Unsightly green and reddish growths (galls) on the upper 
sides of the leaves of soft maple are signs of an infestation of the 
extremely small mites of this species. The mites overwinter on 
the bark of trees and in spring migrate to young leaves, where 
they stimulate the formation of galls, in each of which many 
mites live and feed. It is doubtful if galls associated with this 
species cause enough damage to large, vigorous trees to justify 


Fig. 33. — Maple bladder galls on the upper side of a soft maple leaf. 
Growth of each gall is stimulated by extremely small mites, which live in 
the gall. This mite apparently causes little damage, except possibly to 
small trees. (Photograph from Michigan State University.) 


46 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


spraying. Small trees, struggling for a start, may be benefited by 
spraying. 


Green-Striped Mapleworm, Anisota rubicunda (F.).—An oc- 
casional pest of maple, the caterpillar of this species consumes 
entire leaves, and an infestation may defoliate a tree within a 
short time. The full-grown caterpillar is about 2 inches long. It 
is yellowish-green in color, has green stripes running lengthwise 
on its back, spines on its sides, and two horns on its thorax. The 
adults or moths of this species emerge in early spring from pupae 
in the soil; the female lays eggs on leaves of maples. The insect 
may produce two generations in a year. 


Flatheaded Apple Tree Eorer, Chrysobothris femorata 
(Oliv.), fig. 34. — The larva of this common and widely distrib- 
uted insect attacks a great variety of shade trees and fruit trees. 


Fig. 34.— Flatheaded apple tree borer: A, larva; B, adult, a gray or 
brown metallic-colored beetle about one-half inch long. (Photographs from 
United States Department of Agriculture.) 


Almost any tree that is weakened by transplanting or dry weather 
or is wounded or damaged by sunscald may be invaded by this 
destructive borer. The adults are flat, metallic-colored beetles, 
each about one-half inch long. The female lays eggs in cracks 
and crevices in the bark of a tree; the young borers that emerge 
from these eggs have little trouble in boring through and tun- 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 47 


neling under the bark. Often, trees are girdled by the white, leg- 
less, slender grubs with big flat heads. Feeding mainly in the 
sapwood at first, each grub mines deeper as it becomes larger 
and when grown it makes enough room at the end of a tunnel to 
spend the winter. Pupation and transformation take place in the 
early spring. At this time, an adult emerges through the tunnel 
made by a borer. The life cycle of the flatheaded apple tree borer 
is completed in a year. 


Aphids.—Two species of aphids are pests of maples. They 
suck sap from the under sides of maple leaves and secrete enough 
honeydew, at times, to wet the sidewalks and streets under the 
trees. The Norway-maple aphid, Periphyllus lyropictus (Kess.), 
is a greenish insect that feeds along the veins on the under sides 
of the leaves of Norway maple and hard maple. The painted 
maple aphid, Drepanaphis acerifoliae (Thos.), is gray or black 
in the winged form and yellow in the wingless form. It is more 
common on soft maple than on other maples. Aphids usually do 
not cause enough damage to large trees to justify the expense 
of spraying. 


Pigeon Tremex, Tremex columba (L.).—Associated with 
diseased and dying maples and many other kinds of trees, the 
pigeon tremex may be erroneously blamed as a serious tree pest. 
Each almost 2 inches long and with a reddish head and thorax, 
the adults are wasplike sawflies that bore holes in the trunk of a 
tree; there the female deposits eggs which hatch into grubs that 
live in the infested tree until development and transformation 
are completed. 

A slender parasitic wasp belonging to the great 
family of parasites, the Ichneumonidae, probably does more to 
control the pigeon tremex than could be done with all sorts of in- 
secticides. With her ovipositor, a long threadlike appendage at 
the end of her abdomen, the female of this wasp, with uncanny 
precision, drills into a tremex tunnel and deposits an egg which 
produces a larva that attaches itself to the tremex grub and 
kills it. 

No insecticide treatment is recommended for the pigeon 
tremex. Trees infested by the tremex probably should be cut 
down and removed because they are dying from other causes. 


48 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


OAK 


Borers.—Like other trees when weakened by transplanting 
shock, dry weather, or poor environment, oaks may be attacked 
by several species of borers. The flatheaded apple tree borer 
(see under Maple) and the carpenterworm (see under Poplar) 
are common pests of oaks. 


Periodical Cicada, Magicicada septendecim (L.), fig. 35.— 
The female of the periodical cicada, which seems to prefer the 
terminal twigs of oaks for laying eggs, causes damage by tearing 
the bark and wood where she thrusts eggs into a twig. The dam- 
age resulting from many egg deposits in a twig causes it to die, 
and possibly to break off. Tiny nymphs hatch from the eggs, 
drop to the ground, burrow into the soil, and subsist for a 13- or 
17-year period on the plant juices they can obtain from roots. 
The nymphs emerge from the ground in early summer, attach 
themselves to nearby objects, and molt to become adults. Both 
male and female are black and robust; they have reddish eyes, 
legs, and wing veins. With strident song, the males announce the 
presence of cicadas in great swarms at intervals of 13 or 17 
years. 


May Beetles, Phyllophaga spp.—The adults of many species 
of Phyllophaga (May beetles or June bugs) feed on the foliage 
of oaks and other trees, sometimes in such numbers that they 
defoliate small trees. These adults, which feed at night, are at- 
tracted to lights. Most of the beetles are solid brown in color and 
are one-half to three-fourths inch long. Eggs deposited by the 
female in the soil produce larvae, white grubs, that feed on the 
roots of grasses and other plants. Most May beetles have a 
3-year life cycle. 


Twig Pruner, Elaphidion villosum (F.).—Although not a 
major pest, the larva of this species when present in considerable 
numbers may litter a yard in late summer with twigs from oaks, 
elms, hickories, maples, and other trees. A clever animal, the 
larva tunnels around a twig under the bark, cutting into the twig 
to such an extent that it is easily broken off in the wind. Having 
burrowed farther toward the tip of the twig, the pruner falls with 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 49 


Fig. 35.—Periodical cicada: A, adults on trunk of tree; B, punctures 
made in twig by adult female in laying eggs; C, eggs in tissue of twig. Dam- 
age to oaks is very conspicuous following an outbreak of the cicada. 


50 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


the twig to the ground, where transformation occurs. The adult 
is a rather slender, brown beetle, about three-fourths inch long, 
that emerges from the pupa. The female lays eggs in twigs in 
early summer. 


Oak Kermes, Kermes pubescens Bogue, fig. 36.—Of most im- 
portance on bur oak, but sometimes found on chinquapin, white 
oaks, and red oaks, the oak kermes is closely related to the scale 


Fig. 36.—Oak kermes: an infestation of this almost spherical scalelike 
insect at the base of a new shoot. 


insects. After wintering on the bark of twigs and branches, the 
oak kermes migrates to a growing shoot. Where numerous indi- 
viduals cluster around shoots and on the under sides of the leaves, 
they distort and kill the new growth. The full-grown female 
kermes is about one-eighth inch in diameter, almost spherical, 
light brown in color, and covered with very fine fuzz. The male 
produces a tiny white cocoon, in which it develops. In the spring, 
each female lays several hundred light brown eggs under her 
Shell. In June, the reddish-brown crawlers that emerge from 
the eggs leave the mother shell to find a suitable place for feed- 
ing. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 51 


Leaf Miners, fig. 37.—Leaf miners, larvae of tiny moths, 
flies, sawflies, and small beetles, feed between the upper and 
lower surfaces of the leaves of oaks and many other shade trees, 
where they produce serpentine mines and blotches. Usually the 
female places her eggs on leaf surfaces, and each young larva, 
soon after it is hatched, bores into the leaf and proceeds to tunnel 
in various directions. If a mined leaf is placed in front of a bright 
light before the mine has been abandoned, the small larva that 
did the damage can be seen between the two leaf surfaces. 


Fig. 37Leaf miners: damage to oak leaves. Very small larvae of 
several species of insects “mine” the leaves of oaks and other trees and de- 
stroy the tissue between the upper and lower leaf surfaces. 


5/4 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 38.—Oak galls of three types stimulated by small wasps belonging 
to the family Cynipidae: A, gouty oak gall; B, wool sower gall; C, oak apple 
gall. The abnormal growth of plant tissue is stimulated in some mysterious 
fashion by these insects in the early part of the growing season. Each gall 
contains one or more larval cells. The wasp larvae eventually transform 
to the winged form and abandon the galls. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 53 


Gall-Producing Insects, fig. 38.—Galls appear on oak twigs 
in a variety of sizes and shapes that include irregular, bumpy, 
warty growths and smooth, attractive, spherical formations. 
These galls are not manifestations of a systemic disease and are 
no cause for alarm. One of the unattractive kinds, the gouty oak 
gall, fig. 38A, most often found on red oak, is produced by a small 
wasp belonging to the family Cynipidae. Individual cells, each 
inhabited by a larva of the wasp, make up the inside of the gall. 

A woolly ball an inch or more in diameter, at first white but 
brown when older, is known as the wool sower gall, fig. 38B. 
Also produced by Cynipidae, this gall is not numerous enough to 
cause severe damage. The oak apple, fig. 38C, is another spheri- 
cal gall, green or brown in color, an inch or more in diameter, 
which sometimes occurs in clusters. The spongy mass inside 
each gall has a larval cell. 

Damage to oaks by galls is rarely serious enough 
to justify spraying. Since galls provide protection for the insects 
inside, sprays applied after the galls develop are ineffective. 


PINE 


Sawflies, Neodiprion spp., fig. 39.—The larvae of sawflies 
are often seen as colonies of caterpillars feeding on pine needles. 
They are especially injurious to young pines, which may be killed 
by one defoliation. Each larva, about an inch long when grown, 
has a red, brown, or black head, and many larvae have rows of 
spots running lengthwise of their bodies. The insect overwinters 
in a brown pupal case in the debris under a tree. Each less than 
half an inch long, the seldom-seen, beelike adults emerge in the 
spring. The female deposits eggs in slits she makes in pine nee- 
dles. Although hard to see when first hatched, because of their 
small size, the sawfly larvae soon attract attention by the disap- 
pearance of needles required to meet their appetites. Sawflies 
may produce two generations a year. 


54 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 39.—Red-headed pine sawfly: four larvae and a pupal case (arrow) 
on pine. Rows of black dots are conspicuous on the pale yellow larvae, which 
consume the needles of young pines and may cause serious damage to the 
trees. (Photograph from Pennsylvania State University.) 


White-Pine Weevil, Pissodes strobi (Peck).—This pest pre- 
fers white pine, but it feeds upon Scotch and jack pines, also. 
Damage by the weevil is readily recognized by dead and dying 
terminal leaders of infested trees. The overwintering adults, 
each only about one-fourth inch long, feed on terminal twigs in 
the spring. At this time of year, the female deposits eggs on the 
terminal twigs. The larvae feed under the bark in the same gen- 
eral region, causing enough damage to kill the twigs. 


Pine Needle Scale, Phenacaspis pinifoliae (Fitch), fig. 40.— 
Scales of this species appear as white specks along the needles of 
its favorite hosts, Austrian and Mugho pines, as well as other 
kinds of pines and some spruces. The purple insect under each 
shell sucks out sap and chlorophyll, reduces the vitality of the 
needles, and causes shedding of needles. Reddish eggs, which 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 


Fig. 40.—Pine needle scale: infestation on pine. Scales appear as white 
specks along the needles. (Photograph from Connecticut Agricultural Ex- 
periment Station.) 


56 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


overwinter under the shell of the female, hatch in the early sum- 
mer. Each nymph or crawler moves to a new place, settles after 
a few days, and inserts its beak into the leaf tissue to feed. It 
soon begins to make a shell. This species of scale produces two 
broods of crawlers during the summer. 


Fig. 41.—Pine bark aphid: infestation on white pine. The aphids them- 
selves are inconspicuous, but an infestation is easily recognized by the 
splotches of cottony substance they produce. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES =i 


Pine Bark Aphid, Pineus strobi (Htg.), fig. 41.—White 
patches of cottony substance on the trunks and limbs of pines 
make an infestation of this pest easy to recognize. The insect 
prefers white pine but sometimes feeds on Scotch and Austrian 
pines. Its feeding does little damage to large, thrifty trees but 
may weaken young trees. 

The immature aphid, which overwinters under the “cotton,” 
matures in the early spring and lays yellowish eggs, which also 
are covered with “cotton.” These eggs hatch in June, producing 
both winged and wingless forms. The winged form apparently 
migrates to other pines. The wingless form remains where it was 
hatched and lays eggs which produce the overwintering nymphs. 


European Pine Shoot Moth, Rhyacionia buoliana (Schiff.).— 
The black-headed, brown larvae of this species may cause serious 
damage to Mugho, red, and Scotch pines by boring into the shoots, 
causing them to turn brown and die. The partly grown, over- 
wintering larvae become active in the spring and bore into unin- 
fested shoots; pitch forms at the entrance holes they make. Pu- 
pation occurs in early summer, and the female moth, soon after 
emerging from her pupa, deposits eggs near the tips of twigs. 
Each young larva bores into the bases of needles to feed; feeding 
by the larva causes the needles to turn yellow. Later the larva 
bores into a shoot for the winter. Removal and destruction 
of infested shoots in winter may help control this pest. 


Nantucket Pine Moth, Rhyacionia frustrana (Comst.), fig. 
42.—-The small, yellowish larva of this insect is only about one- 
half inch long. It may kill many tips of red, jack, and other 
pines. The adults, reddish-brown moths, emerge in the spring 
from overwintering pupae. The female deposits flat, yellowish 
eggs on the needles and terminal leaf buds of pines. The larvae 
mine the needles at first but later bore down the centers of twigs. 
They construct delicate webs that enclose the affected needles 
and twigs. Larvae of the first two generations per year pupate 
in buds. 


58 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 42.—Nantucket pine moth: damage to pine shoots by the small, 
yellowish larvae of this moth. Red pines and jack pines are favored by this 
pest. 


Zimmerman Pine Moth, Dioryctria zimmermani (Grote) .— 
The light gray, reddish-yellow, or greenish larva of this species 
tunnels under the bark around limbs and branches of pine, espe- 
cially at the whorls, where it does serious damage. Presence of 
larvae usually can be recognized by the great quantity of pitch 
over the tunnels. Scotch and Austrian pines are particularly 
susceptible to this insect. 

The maximum flight of the adults, which are nocturnal, 
dark gray moths, occurs about the middle of August, when the 
female deposits eggs on the bark of pine. The larvae usually 
work where bark is thin. Pupation occurs in the larval tunnels. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 59 


POPLAR 


The fast-growing poplars, Lombardy, Carolina, aspen, and 
cottonwood, are almost certain to be short-lived because of the 
ravages of borers. Some of these borers are discussed briefly be- 
low. 

Poplar Borer, Saperda calcarata Say.—The white, cylindrical 
larva, which does the boring, and the adults, bluish-gray beetles, 
are each more than an inch long. Eggs deposited in slits in bark 
in the summer produce the borers that work under the bark and 
sapwood and into the heartwood of an infested tree. Frass or 
sawdust at the base of a tree indicates the presence of borers. 
Three years are required for the life cycle of this insect. 


Cottonwood Borer, Plectrodera scalator (F.).—The adult 
form of this insect is a large beetle with long, black antennae. 
The female lays eggs in cavities dug in the bark. The eggs pro- 
duce white, deeply constricted grubs that when grown are up to 
2 inches in length. These grubs, the tunnels of which are plugged 
with wood fibers, work near the bases of trees or even below 
ground. Badly infested trees may be easily blown over. Two 
years are required for the life cycle of this insect. 


Poplar and Willow Borer, Sternochetus lapathi (L.).—The 
larva of this insect is a legless grub or borer, about one-half inch 
long, that bores into poplars and willows. The adults are black 
snout beetles or weevils. The borer feeds in the limbs and 
branches, as well as in the trunk, of the tree it infests. It prefers 
wood 2 or more years old. 


Carpenterworm, Prionoxystus robiniae (Peck).—The larva 
of this insect is a pinkish, slightly flattened caterpillar, up to 
214 inches long, that develops from an egg deposited in a bark 
crevice by a large, gray moth. The carpenterworm requires 3 
years to complete development, during which time the larva 
mines and loosens the bark and drills large holes into the trunk 
of the infested tree. It may deform trees and branches. 


60 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Cottonwood Leaf Beetle, Chrysomela scripta F.—The foliage 
of cottonwood and willow is often skeletonized by the dirty yellow 
larvae of this species. The overwintering form, a beetle about 
one-fourth inch long, has a black head and thorax and yellowish 
wing covers. In spring, it emerges from the debris about a tree. 
The female deposits masses of yellow eggs on the under sides of 
leaves. The larva eats the tissue of leaves, all but the veins, com- 
pletes development in 2 weeks or so, and, attached to a leaf, pu- 
pates with its head hanging downward. This insect provably 
has two broods a year. 


Poplar Tent Maker, Jchthyura inclusa Hbn.—Silken tents 
enclosing a branch or twig of a poplar are signs of colonies of the 
black-mottled caterpillars that are the larvae of this insect. As 
the caterpillars grow, they take more and more leaves into the 
tent. The insect overwinters in the pupal stage. The female moth 
that emerges from an overwintering pupa deposits masses of 
eggs on leaves to produce caterpillars that feed in June. A second 
brood of caterpillars occurs in August. 


Oystershell Scale, fig. 5—This is a common and destructive 
pest of cottonwood. See under Ash. 


PRIVET 


Privet Thrips, Dendrothrips crnatus (Jablon.).—This thrips 
in both adult and nymphal forms is a small, flat, elongate insect 
that feeds in great numbers on privet foliage, withdrawing the 
juices and chlorophyll. The adult thrips, dark brown and yellow, 
have wings. The nymph, almost colorless at first, becomes lemon 
yellow as it increases in size. Privet leaves affected by this insect 
become dotted and dirty with excrement and they fall prema- 
turely. Because this insect feeds at first on the under sides of 
leaves, it often goes unnoticed until the leaves have been severely 
damaged. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 61 


REDBUD 


Redbud Leafhopper, Erythroneura bistrata McAtee, fig. 43. 
—This is the most common of several species of leafhoppers that 
feed in great numbers on the foliage of redbud. With sucking 
mouthparts, the insects feed on the under sides of the leaves, 
withdrawing the plant juices and chlorophyll so that the leaves 
become blanched. The adult, about one-eighth inch long, is 
marked with red. The nymph, similar in shape but smaller, is 
whitish. Both forms are active; adults fly up in small clouds 
when disturbed. This insect has two or three generations a year. 


Fig. 43.—A, leafhopper of the species Erythroneura bistrata, adult 
greatly enlarged; B, damage to redbud leaves by leafhoppers. 


62 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Two-Spotted Spider Mite, Tetranychus telarius (L.).—The 
foliage of redbud trees is sometimes infested with great num- 
beis of green or yellowish mites of this species. The mites remove 
so much chlorophyll and juice from the foliage that the leaves be- 
come dry and drop prematurely. The overwintering female mites 
move to the leaves in early summer to feed and deposit trans- 
lucent, spherical eggs. Six-legged larvae hatch from the eggs in 
a few days. After the first molt, the mites have eight legs. Follow- 
ing two more feeding periods and molts, the mites become adult. 
The mites of various stages differ in size but are similar in ap- 
pearance. Males are slightly smaller than females, and their ab- 
domens are more pointed than those of females. There may be a 
number of generations of this mite during the summer. 


Oystershell Seale, fig. 5—See under Ash. 


SPIREA 


Spirea Aphid, Aphis spiraecola Patch, fig. 44.—This green 
plant louse occurs nearly every spring in great numbers on the 
tender shoots of spirea. Eggs deposited on spirea in the fall give 
rise to mother aphids that produce living young in the spring. 
Wingless and winged forms may be present; the latter migrate 
to other host plants as the plant growth hardens. Quantities of 
sticky honeydew are produced by an infestation of this aphid. 


SPRUCE 


Spruce Spider Mite, Oligonychus ununguis (Jac.).—The 
spruce spider mite is small, but its dense populations can do a 
great deal of damage. It is one of the most troublesome pests of 
arborvitae, spruce, and juniper. It lives on the juices of these 
plants. When the sharp green color of the foliage begins to give 
way to gray, and later brown, it is too late to prevent some de- 
gree of damage, but prompt action may prevent serious damage 
or death of the plants. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 63 


Overwintering eggs at the bases of the needles of infested 
plants produce tiny, light green mites in early spring. Through 
a series of molts the mites mature into larger, darker green, or 
almost black individuals, with spinelike hairs that curve back- 


Fig. 44.—Spirea aphid: infestation of this green plant louse on a spirea 
shoot. After sucking sap from the shoots of spirea for a short time in 
spring, this aphid develops a winged form that migrates to other host 
plants. 


ward over their robust bodies. The mites can be seen as moving 
specks on a white piece of paper or dish that has been held under 
infested branches struck sharply with the hand. This species 
has a number of generations in a season. 


64 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Cooley Spruce Gall Aphid, Chermes cooleyi Gill.—Gall aphids 
of this species produce thick, elongate galls at the tips of twigs 
of Colorado blue spruce, Sitka spruce, and Engelmann spruce. 
The galls are so heavy that usually they cause the twigs to bend. 
In midsummer, the galls open and the aphids emerge. Some of 
the gall aphids develop wings. Gall aphids of the winged form 
migrate to Douglas fir, where the females lay eggs. The eggs 
and young gall aphids are covered with patches of cottony wax. 
No galls develop on Douglas fir. 


Eastern Spruce Gall Aphid, Chermes abietis L.—Gall aphids 
of this species produce somewhat pineapple-shaped galls near the 
bases of spruce twigs. Sometimes these gall aphids cause severe 
damage to Norway spruce. 


Spruce Bud Scale, Physokermes piceae (Schr.), fig. 45.—The 
mahogany-brown, globular scales of this species cluster at the 


de 


Fig. 45.—Spruce bud scale: infestation on spruce. The globular, ma- 
hogany-brown scales resemble spruce buds and are difficult to detect. 


ENGLISH: [LLINOIS TREES. THEIR INSECT ENEMIES 65 


buds and nodes of spruce. The overwintering female fills her 
shell, about one-eighth inch in diameter, with purple eggs in 
June. In central Illinois, the eggs hatch about the first of July. 
The flat, purple crawlers move away from their mother to settle 
in a new place. 


Spruce Budworm, Choristoneura fumiferana (Clem.).—A 
destructive forest pest that sometimes attacks ornamental 
spruces, the larva of this species is a dark reddish-brown cater- 
pillar about 1 inch long when grown. It feeds on the opening 
buds and needles, tying them together with silk. 

The overwintering caterpillar becomes active in the spring 
and completes development. The adults, dull gray moths, emerge 
from the pupal case in midsummer, when the female deposits 
masses of overlapping, greenish eggs on the needles. 


Pine Needle Scale, fig. 40.—See under Pine. 


SYCAMORE 


Sycamore Lace Bug, Corythucha ciliata (Say), fig. 46.—This 
insect is probably the most common pest of sycamore. Both 
adults and nymphs feed on the under sides of the leaves in great 
numbers, withdrawing so much plant juice and chlorophyll that 
the foliage becomes pale and dry. The leaves become dirty with 
excrement. Both male and female are pretty insects; each is 
about one-eighth inch long and has a black body and almost 
transparent, lacelike wings held flat when at rest. By contrast, 
the black, spiny nymph is ugly. 

The overwintering female becomes active in early spring 
and deposits eggs on the under sides of new leaves. The eggs 
hatch in a couple of weeks, and each nymph molts five times be- 
fore becoming an adult, 30 to 40 days later. 


Bagworm, fig. 2.—This, the most common leaf eater on syca- 
more, is discussed under Arborvitae. Sprays applied 
in late summer after the larvae stop feeding, or during the win- 


66 ILLINCIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 46.—Sycamore lace bug: adults. The bugs, which are black and 
have almost transparent wings, are shown congregated on the bark of a 
tree. They have sucking mouthparts and feed on the under sides of leaves. 
(Photograph from Connecticut Agricultural Experiment Station.) 


ter, are ineffective. The worm infestation can be reduced by 
picking and burning the overwintering bags. 

Borers.—Newly set sycamores, like most other newly set 
trees, are subject to attack by borers, especially the flatheaded 
apple tree borer, fig. 34. 


TULIPTREE 


Tuliptree Scale, Toumeyella liriodendri (Gmel.).—Oval, 
brown females of this species may be seen plastered on the bark 
of lower branches and twigs of the tuliptree in summer. Great 
quantities of honeydew drip from the scales. Inconspicuous over- 
wintering nymphs, also plastered on the bark, grow rapidly in 
the spring and early summer. The female reaches maturity in 
August and apparently gives birth to living young. 


Tuliptree Aphid, Macrosiphum liriodendri (Monell).—This 
small, greenish aphid occurs in great numbers on the under 
sides of the leaves of the tuliptree. Honeydew, which is secreted 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 67 


in large quantities by the aphids, makes the leaves sticky and 
drips on objects under the tree. Sooty mold often grows in the 
honeydew and causes the leaves and other objects it covers to 
appear black. 


WALNUT 


Walnut Caterpillar, Datana integerrima G. & R., fig. 47.— 
The larva of this species, a large, black caterpillar with gray 


Fig. 47.—Walnut caterpillar: a colony of larvae. Walnut caterpillars, 
reddish when small, later have black bodies covered with white hair. They 
may completely strip the foliage from the trees they infest. 


68 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


hairs, is the main leaf eater of walnut trees and, for some un- 
known reason, is attracted to isolated trees. It is very fond not 
only of walnut but of butternut, hickory, oak, honey locust, and 
willow; somet:mes it feeds on apple and other fruit trees. Each 
caterpillar develops through a series of molts from one of many 
eggs laid in masses on leaves of the host tree. An egg mass pro- 
duces a colony of caterpillars that may destroy the foliage on a 
whole limb before moving to fresh leaves. The colonies migrate 
downward on a limb or tree trunk, molt, and leave a clump of 
skins the size of a man’s fist. When grown and about 2 inches 
long, the caterpillars leave the infested tree and dig into the soil. 
There they pass the winter in the pupal stage. The adults, 
brownish moths, emerge in early summer. The female flies into 
one of the preferred kinds of trees, where she deposits eggs. 


Black Walnut Curculio, Conotrachelus retentus (Say) —This 
reddish-brown weevil feeds on tender shoots and foliage of wal- 
nut for a while in the spring. The adult female makes, in the 
young walnuts, crescent-shaped cuts in which she deposits eggs. 
Feeding of the larvae that hatch causes the nuts to drop when 
only about half grown. 


Fortunately this walnut pest is attacked by several parasites, 
which help keep it under control. 


WILLOW 


Willow Aphid, Clavigerus smithiae (Monell), fig. 48.—This 
rather large, dusky aphid may infest twigs and leaves of willows 
during the summer. Unlike many kinds of aphids, this one is 
restless, easily disturbed, and rapid in its movements. Both 
winged and wingless forms may be present on an infested tree. 
By withdrawing juices from leaves, this aphid may cause the 
leaves to wilt and drop. 


Bagworn, fig. 2.—See under Arborvitae. 


Borers.—See under Pcplar. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 69 


Fig. 48.—Willow aphid: an infestation of the wingless form on a twig. 
This dusky, relatively large aphid withdraws juices from leaves, causing 
them to wilt and drop. 


Ovstershell Scale, fig. 5—See under Ash. 


YEW (TAXUS) 


Black Vine Weevil, Brachyrhinus sulcatus (F.), fig. 49.— 
Rapid dying of yew—dying similar to that caused by transplant- 


70 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


ing shock—may indicate that the roots have been eaten by the 
white, legless, crescent-shaped grubs of the black vine weevil. 
The grubs feed on plant roots from late summer until late spring. 
Development and transformation of this insect take place in the 
soil, and the adult weevils make their way to the surface about 
the first of June. The adults are seldom observed, as they hide 
during most of the daylight hours and feed sparingly, mainly at 
night, on the foliage toward the center of the plant. The female 
does not deposit her eggs on a plant, as many insects do, but 
simply drops them on the ground. This insect has only one gen- 
eration a year. A long preoviposition period makes it possible to 
time a control spray to kill all adults after they have emerged 
from the soil and before they have dropped eggs. 

From southern to northern Illinois, this 
period may vary from June 15 to July 15. The spray should be 
applied to plants to the point of drenching them. 


Fig. 49.—Black vine weevil: larvae and damage to small yews. The 
adult, a black snout beetle, is seldom seen. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 71 


Fletcher Scale, Lecanium fletcheri Ckll., fig. 50.—This is a 
soft scale, usually occurring sparsely on yew but sometimes as 
heavy infestations that cause serious damage. The overwinter- 


Fig. 50.—Fletcher scale: infestation on yew. The overwintering females 
are pale yellow to brown in color and globular in shape. 


ing female, pale yellow to brown in color and globular in shape, 
lays eggs in May. One scale shell may contain 800 or more eggs. 
The flat, yellow crawlers that hatch from the eggs in June move 
away from the mother shell to settle and feed on new growth. 
This insect has only one generation a year. 


Termites, Reticulitermes spp.—Termites may attack yew, 
especially plants near an infested building. The white, antlike 
insects build mud runways about the base of a plant or in the 
crotches of the branches or along the larger branches. They eat. 


72 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 51.—Taxus mealybug: infestation on yew. The sooty mold on in- 
fested needles makes the white, wingless insects conspicuous. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 73 


the bark and cambium and may girdle and kill a branch or an 
entire plant. 


Taxus Mealybug, Dysmicoccus cuspidatae (Rau), fig. 51.-— 
The taxus mealybug is an occasional pest of yew. Its name is 
descriptive of the white, waxy, slow-moving, sucking insect seen 
feeding in small colonies on the twigs and branches. 


POTENTIAL INSECT ENEMIES 


There are several important shade tree pests that have not 
yet, but may, become destructive in Illinois. Everyone should be 
on the alert for them. Anyone finding an insect fitting one of the 


Fig. 52.—Japanese beetle: adults. Both male and female adults are 
principally metallic green in color and about a half inch in length. Each has 
white spots on the tip of the abdomen. 


descriptions below should place the insect in alcohol and send it 
to the Illinois Natural History Survey, Urbana. Early knowledge 
of the presence of a new pest may result in holding down an in- 
festation or in wiping it out completely. 

Japanese Beetle, Popillia japonica Newm., fig. 52.—The 
Japanese beetle feeds on the foliage of a wide variety of trees, 
shrubs, vines, and other plants. It is a ravenous feeder that oc- 
curs in great hordes. 

A native of the Orient, this insect was first found in the 
United States in 1916, and isolated infestations now occur in 
Illinois. The adults, metallic green beetles about one-half inch 
long, have white spots on the tips of their abdomens, just back 


74 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 53.—Gypsy moth: A, adult females; B, adult males; C, larvae; D, 
egg clusters and pupae on the under side of loose bark. The female is buff 
in color, the male dusky; the larva is covered with brown hair and has blue 
and red tubercles along the back. The egg clusters are covered with tan 
hairs. (Photographs from Connecticut Agricultural Experiment Station.) 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES Ue) 


of the wing covers. They are strong fliers. They are very fond of 
eating ripening apples, corn silk, grape foliage, and soybeans. 
The female deposits eggs in the soil to produce grubs that feed 
on the roots of grasses. The grubs spend the winter in the soil, 
resume feeding in the spring, complete growth, and pupate. The 
adults emerge from the pupae in late June or July and feed for 
several months. This insect produces one generation each year. 

Gypsy Moth, Porthetria dispar (L.), fig. 58.—Of all the leaf- 
feeding pests that attack shade and woodland trees, the cater- 
pillar of the gypsy moth is the most destructive. It feeds on 
nearly all deciduous trees, and, except in the early stages of its 
development, on many evergreens. Most of the area infested by 
this insect lies east of the Hudson River. An infestation in Mich- 
igan was discovered a few years ago, but there is some hope of 
eradicating it. 

The female moth deposits eggs in hair-coated clusters on 
tree trunks, buildings, and other objects. The full-grown cater- 
pillar, 2 to 214 inches long, is covered with tufts of long brown 
hair and has five pairs of blue tubercles along the back followed 
by six pairs of red tubercles. 

The insect overwinters in the egg stage. The eggs hatch as 
the leaves of trees unfold in spring. The caterpillars feed for 
about 2 months, during which time they may strip trees of their 
foliage. Pupation occurs in cocoons fastened to tree trunks. The 
adults emerge in late July, and the female deposits the eggs that 
carry the species through the winter. The female is buff in color, 
the male brown. 

Brown-Tail Moth, Nygmia phaeorrhoea (Donov.).—The cat- 
erpillar of this species feeds on the foliage of a wide variety of 
trees, including oak, elm, maple, willow, apple, pear, and plum. 
Like the gypsy moth, the brown-tail moth is confined mainly to 
the New England states. 

The male as well as the female is white, except on the tip of 
the abdomen, which is covered with brown hairs. The caterpillar 
is reddish brown and has a broken yellow stripe along each side 
of its body. The body is covered with stiff barbed hairs, which 
may cause a very irritating rash on human beings. 

The partly grown caterpillar, which overwinters in a nest of 
webbed leaves, feeds for a while in the spring before pupating. 
The adults emerge in July, and the female deposits masses of 
brown eggs on the under sides of leaves. 


76 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


ABOUT INSECTICIDES 


All insecticides should be handled as poisons. Some are more 
poisonous to human beings than are others, and some are so haz- 
ardous that they should be handled only by persons familiar with 
them. The first step in handling all insecticides safely is to read 
the label on the package, and the second is to follow the instruc- 
tions given thereon. 


An overdose of a chemical may cause plant damage. In gen- 
eral, insecticide applications should be made only when a pest 
species is causing enough damage to destroy the aesthetic value 
of an ornamental plant. Many insect pest populations are held 
in check by parasites and predators. The indiscriminate use of 
pesticides sometimes results in severe plant damage, because 
the chemicals eliminate parasites and predators of pests, re- 
sulting in a population resurgence of an insect or mite species 
which was previously controlled by natural enemies. Generally, 
certain developmental stages of a pest are more susceptible to 
chemical control measures than are other stages; therefore, 
the timing of chemical applications is very important. 


Although insecticide applications are depended upon for the 
control of most insect pests of trees and shrubs, other measures 
are sometimes used: syringing mite infestations on plants with 
a strong stream of water; picking and burning the overwintering 
bags of bagworms to destroy the eggs; covering young trees with 
cheesecloth to protect them from cicadas; wrapping the trunks 
of young trees with paper to protect them from borers, fig. 54. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 77 


Fig. 54.—Newly set tree, A, wrapped with paper to prevent damage by 
borers. The paper, about 4 inches wide and specially designed for wrap- 
ping trees, is spiraled about the trunk of the tree and held in place with a 
stout cord, as shown in B. 


ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


ABOUT SPRAY EQUIPMENT AND ITS USE 


A 2- or 3-gallon knapsack sprayer, fig. 55, is the smallest 
equipment suitable for spraying shrubbery and small trees. The 
low pressure and low rate of discharge of such equipment demand 


Fig. 55.—Compressed air sprayer, a convenient sprayer for small jobs. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 719 


careful work for complete plant coverage. The trombone-type 
sprayer, shown in the frontispiece, develops adequate pressure 
and is convenient for spraying a few shrubs and small trees. The 
bucket-pump sprayer, fig. 56, also develops adequate pressure for 


Fig. 56.—Bucket-pump sprayer, an inexpensive but suitable sprayer for 
shrubs and small trees. The spray material is mixed with water in a bucket 
and kept mixed by agitation with a wooden paddle. 


80 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


small trees and is useful for treating a larger number of plants. A 
hand-operated wheelbarrow-type sprayer or small power sprayer, 
fig. 57, is recommended for any job involving medium-sized plants 
or a large number of small plants. 

Adequate spraying of large trees requires power equipment. 
A conventional hydraulic sprayer, fig. 58, that develops 500-600 


Fig. 57.—Small power sprayer. This is a satisfactory sprayer for shrubs 
and small trees. 


pounds pressure and has a pump that delivers 30—40 gallons per 
minute is suitable for spraying large trees. However, if all the 
spraying is done from the ground, a great deal of spray will be 
wasted in trying to reach the tops of tall trees. Waste can be 
reduced if some of the spraying is done from a tower built on the 
sprayer. 

A mist blower, fig. 59, is more suitable than a hydraulic 
sprayer for use with large trees. In the mist blower, a spray con- 
centrate is discharged into a blast of air that travels through an 
outlet at a velocity of 100-120 miles per hour. The outlet can be 
manipulated to direct the spray concentrate to all parts of even 
large trees. 


ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES §1 


Incomplete spray coverage of a tree may serve to check the 
ravages of a leaf eater, such as the cankerworm, but control of 
scale insects or control of the bark beetle that transmits Dutch 
elm disease requires complete coverage. This is difficult to obtain 
even with the best of equipment. The tree must be sprayed sys- 
tematically from many angles and at a time when the wind ve- 
locity is essentially zero. Careful inspection of a tree or shrub 
after spraying shows whether proper coverage has been obtained. 


ell OOM AG 


Fig. 58.—Power sprayer in operation. This machine, known as a hy- 
draulic sprayer, will do an excellent job of spraying trees of small and 
medium sizes. 


82 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Fig. 59.—Mist blower or roto-mist sprayer in operation. This machine 
is particularly useful for spraying large trees. 


INDEX 


This index includes technical and common names of insects and com- 


mon names of trees and shrubs. 


Page numbers of illustrations are indicated 


by boldface type. A page number for a subject may indicate the beginning 
of the section or subsection in which the subject is discussed. Names are 
listed in the singular regardless of whether they appear in the text as 
singular or plural. The name of an insect or disease may refer either to the 
thing itself or to the damage it causes. 


A 
Aceria snetsingeri 36 
Agrilus anxius . ial 
Ailanthus hs 
webworm : 3,4 
American elm (see “also 
Elm) : Les Bil. 2B, BS) 
Anisota rubicunda a pee G 
Aphid . if, Bs AG We 
boxelder , ei ae. 12 
Cooley spruce gall 20, 21, 64 
Eastern spruce gall eno: 
elm 
cockscomb gall a2Z9 
leaf ; 28, 29 
Norway- maple 47 
painted maple = aly 
pine bark 56, 57 
spirea . 62, 63 
tuliptree . 66 
willow 68, 69 
woollyelm ... 29 
woolly hawthorn Ae ily 17 
Apple. . 12, 16, 68, 75 
oak (gall) . 5 he 
tree borer, flatheaded > 46; 46, 48 
Aphis spiraecola 62 


Arborvitae 
leaf miner 


5, 39, 43, 62, 65, 68 
F ; 6 
Argyresthia thuiella 


Sure 6 
Ash 6, 24, 40, 60, 62, 69 
borer . : 4 7, 
borer, red- headed 6,7 
mountain 7-8 
Aspen .. 59 
Aspidiotus 
ancylus 28 
perniciosus 18 
Atteva aurea . 3 age 3 
Austrian pine 54,57, 58 


Bagworm. 5,5, 389, 43, 65, 68, 76, 77 
Banded elm leafhopper. . . . 33 
Bark 
aphid, pine 56, 57 
beetle 
hickory 36 
juniper 38 


83 


native elm < abel 
smaller European elm. 31, 32 
Beetle 

elm leaf . 24, 25 
cottonwood leaf . 60 
hickory bark . 386 
Japanese 73, 73 
juniper bark 6 he! 
May. 48 
native elm bark 31 


smaller European elm bark 31, 32 


Birch 11 
borer, bronze 11 
skeletonizer 11 
white 11 

Bittersweet 33 

Black 
cherry 12 
locust 40 
vine weevil — : 69, 70 
walnut curculio 68 

Bladder gall, maple 45 

Bladder-gall mite, maple 45 

Blue spruce, Colorado . . 64 

Borer . 1 sks, oh 66, 68, 17 
ashwieie 5 "1, 8 
bronze birch | 11 
cottonwood 59 
dogwood 3 20 
elm . 2 29, 31 
flatheaded apple tree 46, 46, 48 
locust 40 
lilae 40, 41 
oak 48 
poplar 59 
poplar and willow . i 59 
red-headed ash 6,7 

Boxelder sels Bian. oles 
DUCwR aaah autokey he 2 lalieed2 
aphid Lay Meche Se Misa Licy 

Boxwood 5 él 
leaf miner ; 5 Me) 

Brachyrhinus sulcatus . 69 

Bronze birch borer Pons! lil 

Brown-tail moth ‘ 5 TS) 

Bucculatrix canadensisella ell: 

Bud scale, spruce . : 64, 64 

Budworm, spruce 5) Gb 

Bug 
boxelderwey eee ee lela 
June j ee! NESTA | aS 
sycamore lace 65, 66 


84 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Burioakee ee os 8 eee oe 50 
Butternut’; 4s Gees es 2! 2. 468 


Cc 


Cankerworm, spring 


ecda2a 2s 
Carolina poplar rece (D9 


Carpenterworm 48, 59 
Catalpa 14,15 
sphinx Sever as aes te eek MARS 
Caterpillar yee ee ee eG 
eastern tent 6 ao oy dl ile: 
walnut sets 67, 67 
yellow-necked 1g, 17, 36 
Ceratomia catalpae .. . 14 
Chermes 
QbICtiSy 34 ae aoe. ae ert Od 
COMIGR o 6 65 6 20, 64 
Chermys black 4) 4) ree eS 
Came Glin gf 6 6 o 6 56 6 a He 
Chinquapinwe eee ae O 
Chionaspis 


COTM! a iss, ae ey ee eee 
LUG ULNG od ce eae Os) a eee 
Chokecherry .. . eee a le 
Choristoneura fumiferana eee (815) 
Chrysobothris femorata . . . 46 
Chrysomela scripta . .. . . 60 


Cicada terse hea ae Be TT, 

periodical 48, 49 
Citheronia regalis . ..... 387 
Clavigerus smithiae. . . . . 68 
Cockscomb gall 

aphidielia ars. Gace js caves, eho 29 

elmies)e Rha tier tee 30 
Colopha ulmicola we ahr eit SOO 
Colorado blue spruce ... . 64 
Comstock mealybug ..... 16 
Conotrachelus retentus  . 68 
Cooley spruce gall a 20, 21, 64 
Corn silk .. Q 75 
Corythucha ciliata Dts eee OD 
Cottonwood : 59, 60 


Borer Paty ie at eens Yt cing 
een? lose og ob a 6 5 6 5) GO 


Cottony maple scale 43, 44 
Crab ; : 16, 36 
Curculio, black walnut cl cake EME S 
Cynipidae RM: fe eee ney ey De 
(Chymwloviey Tron 6 oo 6 « oo | B® 
D 
Datana 
AINLCGENTUMIG ©. tas eee ae Gi 
ministra . . . Sel) eae WG: 
Dendrothrips ORDE me eo sant) 


Devil, hickory horned ... . 37 
DIGI OUS COFLIA 5 a 9 co o 0. 0 eM 
Dichomeris marginella . .. . 88 
Dioryctria zimmermani. . . . 58 


Dogwood)... 4) eee 


borer... 2". (2 eee 
scale... sss =O 
Douglas fir é A 20, 21, 64 
Drepanaphis acerifoliae Me oe Yl 
Dutch elm disease 31, 32 
Dysmicoccus cuspidatae . . . 73 
E 
Eastern 


spruce gall aphid .... . 64 


tent caterpillar . ‘ 12,13 
Elaphidion villosum. . 48 
limi lai 2 25 265 2ie 28, 32, 48, 75 

American 5 ‘ PAL PB) Bie: 

aphid, woolly ... . 29 

bark beetle 

smaller European . 31, 32 
mative: << \s. 2 ‘cause atone 
borer ode 00 eo mee 

Chinese . . «4 eee 4 

cockscomb gall solve eee ties 0 

aphid . . +. on ee 
disease, Dutch Aerolerae 
leaf 

aphid 28, 29 


beetle . ae, 
leafhopper, banded . eos 


scale, European 2. 2b e26 
Soemnoranl 6 oo 6 o co ow AW 
Engelmann spruce .... . 64 
Ennomos subsignarius ... . 40 
Eotetranychus multidigituli . . 48 
Eriosoma 
QMeTrICanNUN) pO 
crataegi . . ao) eG 
Erythroneura bistr ata i. GeO 
Huonymus) eee 
scale. <« 4. 3 boa SOO noe 
European 
elm 
bark beetle, smaller . 31, 32 
scale. 5 CUR ee 2 eG 
pine shoot moth & usin ee eG 
red mite. . . 5... \s, Kum 


Fall webworm . . se OS OR 24! 
Flatheaded appletree panes 46, 46, 48 


Fletcher scale nelle 
Fir, Douglas 20, 21, 64 
G 
Galemuicella lnteola 1. eee 


Gall oi. nm % = -) 5 ee 


aphid 
Cooley spruce . 20, 21, a 
‘Oa 


eastern spruce 


ENGLISH: 


elm cockscomb ... . . 29 
elmmecockscomb . «= .. «= « 30 
SOUUVTOAK. « <q s,s. 3 ts 
maple bladder . « . «.« « 45 
mite, maple bladder- . .. . 45 
oak apple _.. dei 
phylloxera, hickory . Spits akc eteae l 
psyllid, hackberry “unele Be 8S 


wool sower . . ) O2n0e 
Gall- nce 

insect . ah BR: 

MITE ey < PES 
Gouty oak gall 52, 53 
GOSSYpATiGSPUTAG . «) » «=. 2d 
Grape . . cme «LD 
Green- striped mapleworm eG 
Gypsy moth Shee ve 74, 75 

H 

Hackberry 35, 35 


nipple gall psyllid A ‘ a 5 Ou Bt 


witcnes’-broom 35, 36 
Hard maple ae 
Hawthorn NGS Wri HE ae 

aphid, woolly 16,17 

leaf miner . Nee 19, 20 
Hemerocampa leucostigma Slots of 33 
FUIGKORVANN - es oo -s , 2 ) BONASNES 

bark beetle Soo ABS 36 

Palephnylloxera . . ue io 

MOMNeUCeVIl =. .aieeea 20s BO 
Homadaula anisocentra . .. . 48 
Honey locust. . . 42, 48, 68 
Horned devil, hickory sun areal 
Hylurgopinus TUSLDES as On 
Hyphaniria cunea. 2 2S 8 

1 
Kehnneumonidae 9s s . 2. en a 
Fehthyura inclusa . .-. . . . 60 
Insect enemies, potential . . . 73 
Insect 
gall-producing : 3515353 
SCALA en, Sie eS ea 2. 
J 
Jack pine .. . 54, 57, 58 
Japanese beetle 5 (eh 78: 
NER DUS ts ic us ws . 48 
Juniper . cL meee, 6, 37, 38, 62 

bark beetle : ‘ 38 

seale 6, 37 , 38 

webworm » Oo, 39 

K 
Kermes, oak . 50.50 
Kermes pubescens . ..... 50 


ILLINOIS TREES: THEIR INSECT ENEMIES 85 


L 
Lace bug, sycamore 65, 66 
Lady beetle és 
Leaf 
aphid, elm . 28, 29 
beetle 
COGLONWOOd yy. a oleae aoe oOU 


elm Be Woh ses Aah es 
CALIBRE. aro UE Silos Jue 


miner Sous. mae O Lol 
ar borvitae | Ses ees 6 
DOXWOOUL ames ls) so =. | coerce l 
hawthorn oe eee oes OT) 
ODA I hen oe te teen Ll 
Leafhopper 
banded a cling-nervey uae ics ee aeo 


redbud . Songs OE a ake 
LOR OVD, TIBLDOETD 6 a a po 8 al 
Lepidosaphes ulmi .: ... 8 
Leptocoris trivittatus: > 15... V1 


Lilae oS eee os 2d 40.41 
bOreEN fo kcca sees (40541 
cindenw = aeeee A) Be touerenee ae i0) 
moth, snow- white wack ses 140 
THOCUStHWS: ace Ske ete 0 
Dla Ckikes sso se eae ta ees O 
ORCS 3.922. \ePrass eben 40 
honey “42, 43, 68 
6 + Se ce eC 43 
Lombardy poplar a on ea eR 
Louse (lice); plant, 202. 2). ..8 2 


M 


Macrosiphum liriodendri . . . 66 
Magicicada septendecim . . . 48 
Malacosoma americanum ... 12 


Maple 6, 14, 43, 47, 48, 75 
aphid 
INOmwayj) eo) uf WORT. 
painted” = owas a eee a7 
lola eel 5 a 4 o 5 s 2 IE 
bladder- ‘dene mite . 5 GiB aR 
lagweael 5c i et bear 7 
IMGTARERY ce toe net ee, wee cue ae 47 
scale, cottony . . 43.44 
SOtt a wei oa cee * 43- 4, 44, 45, 45 
Mapleworm, green-striped . . 46 
Mavyabeetle: 982 1.5 2. 4 « | 48 
Mealybug 
COMStCCKs aa) eb bee ot cee eG 
cassie. 72, 73 
Megacyllene robiniae . Peters wey ety) 
IMtimrOSalie? PARE eet ees Aaa ct KES 
WEbDWOLMU Be aos Ske a ons 
Miner 
aNdooraaueys Weehe 5 5 6 5 6 6 (& 
boxwoodileafi 9). =) eae 14 
hawthorn leaf 19. 20 


ffoakd| leas +9.) cm ~ cca yea 


86 
Mite : 6 oy ey, 16 
European red foe as eS 
gall-producing Hey insets) 
locust . > 48} 
maple bladder- gall . 45 
spruce spider ‘ 6, 39, 62 
two-spotted spider 33, 62 
Monarthropalpus buxi 14 
Moth 
brown-tail 75 
cynthia : : 5 
European pine shoot 5 5. DI 
gypsy .. ns 74, 75 
Nantucket pine 57, 58 
regal . 5 Ot 
snow- -white linden . 40 
white-marked tussock 23, 24 
Zimmerman pine 58 
Mountain ash 7-8 
Mugho pine . . : 54, 57 
Myzocallis ulmifolii 2929 
N 
Native elm bark beetle hol Gul 
Nantucket pine moth 5 57, 58 
Needle scale, pine ‘ 54, 55, 65 
Neoclytus acuminatus 6 
Neodiprion spp 53 


Nipple gall psyllid, haekberry 35 
Norway maple . ‘ 47 
Norway-maple aphid 47 
Norway spruce ‘ 64 
Nygmia phaeorrhoea . US) 
oO 
Osaka 14, 48, 51, 53, 68, 75 
apple gall . Rae EO eS 
oh 4 14 50 
gall 
gouty 52,53 
wool sower 52,53 
kermes 50, 50 
leaf miner aod aul 
red . 50, 53 
white Bd Poets Ve Lei oO 
Oligonychus ununguis : 62 
Oystershell scale . 8,9, 40, 60, 62, 69 
P 
Pachypsylla celtidismamma 35 
Pachysandra 5 Be 
Painted maple aphid ~ AT 
Paleacrita vernata su ale 
Panonychus ulmi . me oS 
Pear .. > TS) 
Periodical cicada 48, 49 
Periphyllus 
lyropictus 47 
negundinis 12 


ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Phenacaspis pinifoliae 54 
Phloem necrosis ; 33 
Phloeosinus dentatus . 38 
Phyllophaga spp. 4 48 
Phylloxera caryaecaulis 37 
Phylloxera, hickory gall 37 
Physokermes piceae 64 
Pigeon tremex AT 
Pine . 53, 54, 55, 58 
Austrian . 54, 57, 58 
bark aphid : 56, 57 
jack . 54, 57, 58 
moth 
Nantucket 57, 58 
Zimmerman 5 Se 
Mugho : 54, 57 
needle scale . 54, 55, 65 
red . 57, 58 
sawfly, red- headed . Bee tay, | 
Scotch . 54,57, 58 
shoot moth, European Ut iaeger( 
white se, 54, 56, 57 
Pineus strobi . NOMAD 
Pissodes strobi 54 
Plant louse (lice) . 2 
Plectrodera scalator 59 
Plum 715 
Podosesia 
syringae 
fraxini el okt | 
syringae . 40 
Popillia japonica Tes 
Poplar 48, 59, 68 
and willow borer = Be 
borer 59 
Carolina . 59 
Lombardy 59 
tent maker . 60 
Porthetria dispar 75 
Potential insect enemies 73 
rrionoxystus robiniae 59 
Privet 60 
thrips . , 60 
Profenusa canadensis 20 
Pruner, twig . . S 48 
Pseudococcus comstocki La . 16 
Psyllid, hackberry nipple gall 5 ae 
Pulvinaria innumerabilis . . . 43 
Putnam scale 27, 28 
R 
Redbud aren 61, 61 
leafhopper 61, 61 
Red-headed 
ash borer . 6, 7 
pine sawfly . 54 
Red 
mite, European . 18 
oak yae: 50, 53 
pine . 57, 58 
Regal moth . 37 


ENGLISH: ILLINOIS TREES: 


RenICULItErmes SPP: « «= =. « . Wl 


Rhyacionia 
(NDING 5. Sa AT eee 5h 
WUESEGON(G ss) Se) ey dime yicom ed PO 
Ss 
MUIONCUMERIG:, = 6. < som oe 1D 
Nonmeosescale. . . . . « . 18,18 
Saperda 
PILLCU LULU Vat) AIR oS as Oe DO 
PIVLCMUOCLO Ty ss Se) ee ee 2D 
Sawfly .. Ser a eae DS 
red-headed pine Ry et Gat ay| 
Scale ae SSO IRR Aa! = Tee. 76 
cottony maple 43, 44 
GGewWoodeks = 7s «das. 1's 220 
euonymus seg 33, 34 
Buropeanvelm. =. =. . . 25, 26 
Fletcher ae Tol, Al 
VES SOiy Ay Aes Deere ye 
juniper . . 6, Cn 38 
oystershell — 8. 9, 40, 60, 62, 69 
pine needle . : 54, 55, 65 
Putnam 27, 28 
San Jose. 18,18 
seurfy 26, 27 
spruce bud 64, 64 
tuliptree . . A re) a OD 
Scaphoideus luteolus ee ek oS 
Scolytus 
THISEMIQEUS . «5 sw BT 
QUuadrwSDINOSUS, = 5 . . . = 36 
Scotch pine 54, 57, 58 
Seurfy scale . eae 5 AG, il 
Shadbush . . tetas eMeo 
Shoot moth, European piness se ea 
Sitka spruce . . eke Lat G8 iss BOA 
Skeletonizer, birch - Se Keke ail cet imeh Pole: 
Smaller European 
elm bark beetle . Sill, 3 
Snow-white linden moth . . ie 
Soft maple 43-4, 44, 45, 
NOVOCAMU et out kee td sl a eile = 
Spanworm,elm . . ~ 5 40 
Sphaerotheca phytoptophila 5 6 OE 
Spaimsescatalpa . s.0ea 2. 2) wdealS 
Spider mite 
spruce . sie ote cs 6, 39, 62 
two- spotted . 33, 62 
Spirea 62, 63 
aphid R Sens 62, 63 
Spring “galerie | Bo al, Re ee 
Spruce Ble eis aneOn Good 
bud scale Salis 64, 64 
budworm . Se bathed) Soe ore aa e OD 
Colorado blue... . aaa 64 
Emceimann $s, «sy alga. G4 
gall aphid 
Cooley 5 AY; ee! 
eastern Si 5 Oe 


THEIR INSECT ENEMIES 8&7 


INOR WAY: 2! 6 Jct econ alee eed 
SUCCES wt 5) ular UL hulankc. eae O4 


spider mite 6, 39, 62 
Sternochetus lapathi é aa: 
SVCAMOLE. 2 Fee sal rh ea Tue OD 

lace bug . 65, 66 

T 
Raxusm(seeralsomview)" 2) 2s) e48 69 

mealybug Bh eevee UP4, 033 
Tent 

caterpillar, eastern 1. 3183 

Maken wpODlAT ee meyer AGO 
Termite .. Bee cs ae weg iL 
Tetranychus telarius 33, 62 


Thamnosphecia scitula . . . . 20 
Rhripss privet 7 60 
Thyridopterix ephemeraeformis 5 
Toumeyella liriodendri 


Tree 
borer, flatheaded aD : ee 46, 48 
of heaven oe vO 
TF CMCUCUIGDG ths pan) tet, A 
AMRGINE, TOE g 5 6 of alo 5 YY 
‘Buliptrecicty no. cy tebe ke tality ee L6G 
aphidusnrs. Voy ty a uae rat ines) he 66 
Scaleuce = 66 


Tussock moth, white- marked 23, 24 
Twig pruner ‘ wae 48 
Two-spotted spider mite : ” 33, 62 
U 


Unaspis*euonymtr 2.2) 8-3 = 933 


Vv 


Vasates quadripedes. ... 45 


Vine weevil, black 69, 70 
WwW 
Wialnita tot ey ss le, ee GT, 
caterpillar Be 67, 67 
CULCUNOblacksar aealn ane GS 
Weevil 
black vine . 69, 70 


wyhiitespine iwhe jabs bsg. Ba 
Webworm 


ailanthus 5) JS ee ao ome e. 
fad cn eee a a ODN Od 
juniper . 38, 39 
mimosa . 42, 43 
White- marked tussock moth . 28, 24 
White 
birch’. 70. anh ees yo el 
OAK ke. Gi Petey a te te ee 0 
pine 54, 56, 57 
weevil é 
Willow 60, 68, 75 


88 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 


Willow—continued Y 

aphid MES hy, ane WOO RED 

borer, poplar and ... . . 59 #£Yellow-necked caterpillar 16,17,36 
Witches’-broom 35,36 Yew (taxus) : 69, 70, 71, 72 
Wool sower gall seth te RONDO 
Woolly Z 

elmbaphidy 2) mee) eee 29 

hawthorn aphi . . . 16,17 Zimmerman pine moth .... 58 


SPRAY PREPARATION TABLES 


Table 1.—Proportionate quantities of liquid insecticides required to make 
various quantities of spray. 


Gallons 
of Spray Quantity of Liquid Insecticide 
Desired 
100 1 pint 1 quart 1 gallon 2 gallons 
50 VW pint 1 pint 2 quarts 1 gallon 
D5 V4 pint Vg pint 1 quart 2 quarts 
5 2 tablespoons 4 tablespoons 6 ounces 12 ounces 
1 1 teaspoon 2 teaspoons 3 tablespoons 5 tablespoons 
| 


Table 2.—Proportionate quantities of powdered insecticides required to make 
various quantities of spray. 


~~ Gallons 
of Spray Quantity of Powdered Insecticide 
Desired 
100 1 pound 2 pounds 4 pounds 8 pounds 
50 V% pound 1 pound 2 pounds 4 pounds 
25 14 pound V4 pound 1 pound 2 pounds 
5 1 tablespoon* 2 tablespoons* | 4 tablespoons* 8 tablespoons* 
1 1 teaspoont 2 teaspoonsf 4 teaspoonst 8 teaspoons t 


*Heaping 


jLevel 


‘ONALD F. LABISKY, Ph.D., Wildlife Specialist 
VILLIAM L. ANDERSON, M.A., Associate Wildlife 
Specialist 

V. W. CocHRAN, JR., B.S., Associate Wildlife 
Specialist 

'HARLES M. NIXxoNn, M.S., Associate Wildlife 
Specialist 

-ENNETH E. SMITH, Ph.D., Associate Chemist 


ICHARD E. WARNER, M.S., Associate Wildlife 
Specialist 

-ONALD L. WESTEMEIER, M.S., Associate Wildlife 
Specialist 

TEPHEN P. HaAveRA, M.S., Assistant Wildlife 
Specialist 

JAVID R. VANCE, M.S., Assistant Wildlife Specialist 
(ONALD E. Duzan, Junior Professional Scientist 


[ELEN C. SCHULTZ, M.A., Junior Professional 
Scientist 


}|LEANORE WILSON, Junior Professional Scientist 
HARON FRADENBURGH, B.A., Laboratory Technician 
OBERT D. CROMPTON, Field Assistant 

AMES W. SEETS, Technical Assistant 


IONSULTANTS AND RESEARCH AFFILIATES: 


Section of Administrative Services 
RoBeErRT O. Watson, B.S., Administrator and Head 


Supporting Services 


WiuMA G. DILLMAN, Property Control and Trust 
Accounts 

Parry L. Duzan, Technical Assistant 

RosBeErT O. Evuis, Assistant for Operations 

LARRY D. Gross, Maintenance Supervisor 

Lioyp E. HuFrrMan, Stockroom Manager 

J. W1tuLIAM Lusk, Mailing and Distribution Services 

JERRY MCNEAR, Maintenance Supervisor 

MELVIN E. SCHWARTZ, Financial Records 

JAMES E, SERGENT, Greenhouse Superintendent 

RICHARD WILSON, Technical Assistant 


Publications and Public Relations 


RoBERT M. ZEWADSKI, M.S., Technical Editor 
SHIRLEY MCCLELLAN, Assistant Technical Editor 
LAWRENCE §8. Faruow, Technical Photographer 
Luoyp LEMERE, TZechnical Illustrator 


Technical Library 


Doris F. Dopps, M.S.L.S., Technical Librarian 
Doris L. SUBLETTE, M.S.L.S., Assistant Technical 
Librarian 


SYSTEMATIC ENTOMOLOGY, RODERICK R. IRWIN, 


thicago, Illinois; WILDLIFE RESEARCH, WILLARD D, KuIMSTRA, Ph.D., Professor of Zoology and Director 
f Cooperative Wildlife Research, Southern Illinois University; PARASITOLOGY, NORMAN D. LEVINE, Ph.D., 
-rofessor of Veterinary Parasitology, Veterinary Research and Zoology and Director of the Center for 
Iuman Ecology, University of Illinois; ENTOMOLOGY, ROBERT L. METCALF, Ph.D., Professor of Zoology 
nd of Entomology, University of Illinois; and GILBERT P. WALDBAUER, Ph.D., Professor of Entomology, 
Tniversity of Illinois; STATISTICS, Horace W. Norton, Ph.D., Professor of Statistical Design and Analysis, 
Iniversity of Illinois. 


Some Publications of the ILLINOIS NATURAL HISTORY SURVEY 


BULLETIN 


Volume 31, Article 3.—Nutritional Responses 
of Pheasants to Corn, with Special Refer- 
ence to High-Lysine Corn. By Ronald F. 
Labisky and William L. Anderson. July, 
1973. 26 p., index. 

Volume 31, Article 4—An Urban Epiphytotie 
of Phloem Necrosis and Dutch Elm Dis- 
ease, 1944-1972. By J. Cedric Carter and 
Lucile Rogers Carter. May, 1974. 31 p., 
index. 

Volume 31, Article 5.—Larvae of the Seri- 
eothripini (Thysanoptera: Thripidae), with 
Reference to Other Larvae of the Tere- 
brantia, of Illinois. By Thomas C. Vance. 
August, 1974. 64 p., index. 

Volume 31, Article 6.—Root Infection of 
Woody Hosts with Verticillium albo-atrum. 
By Gerald L. Born. August, 1974. 41 p., 
index. 

Volume 31, Article 7—The Mecoptera, or 
Scorpionflies, of Illinois. By Donald W. 
Webb, Norman D. Penny, and John C. 
Marlin. August, 1975. 66 p., index. 

Volume 31, Article 8—An Electrofishing Sur- 
vey of the Illinois River, 1959-1974. By 
Richard E. Sparks and William C. Starrett. 
August, 1975. 64 p., index. 

Volume 31, Article 9.—Pesticides and En- 
vironmental Quality in Illinois. By Robert 
L. Metcalf and James R. Sanborn. August, 
1975. 56 p., index. 


BIOLOGICAL NOTES 


86.—Illinois Birds: Tyrannidae. By Richard 
R. Graber, Jean W. Graber, and Ethelyn 
L. Kirk. February, 1974. 56 p. 

87.—The Literature of Arthropods Associ- 
ated with Alfalfa. I. A Bibliography of 
the Spotted Alfalfa Aphid, Therioaphis 
maculata (Buckton) (Homoptera: Aphi- 
dae). By D. W. Davis, M. P. Nichols, and 
E. J. Armbrust. February, 1974. 14 p. 

88.—The Literature of Arthropods Associ- 
ated with Alfalfa. II. A Bibliography of 
the Sitona Species (Coleoptera: Curcu- 


lhionidae). By W. P. Morrison, B. C. Pass 
M. P. Nichols, and E. J. Armbrust. Feb! 
ruary, 1974. 24 p. | 

89.—The Life History of the Spottail Darter 
Etheostoma squamiceps, in Big Creek, Ti! 
nois, and Ferguson Creek, Kentucky. By 
Lawrenee M. Page. May, 1974. 20 p.— 

90.—A Bibliography of the Northern Corr 
Rootworm, Diabrotica longicornis (Say) 
and the Western Corn Rootworm, Dia 
brotica virgifera LeConte (Coleoptera® 
Chrysomelidae). By W. H. Luckmann 
H. C. Chiang, E. E. Ortman, and Marthe 
P. Nichols. April, 1974. 15 p. 

91.—The Distribution of Periodical Cicaday 
in Illinois. By Lewis J. Stannard, Jr 
February, 1975. 12 p. 

92.—The Literature of Arthropods Associatec 
with Soybeans. IV. A Bibliography of the 
Velvetbean Caterpillar Anticarsia gemma 
talis Hiibner (Lepidoptera: Noctuidae) 
By B. J. Ford, J. R. Strayer, J. Reid, ané 
G. L. Godfrey. February, 1975. 15 p. 


93.—The Life History “of the Stripetai) 
Darter, Htheostoma kennicotti, in Big 
Creek, Illinois. By Lawrence M. Page 


February, 1975. 15 p. 
94.—Illinois Pheasants: Their Distribution 
and Abundance, 1958-1973. By Ronald FY 


Labisky. February, 1975. 11 p. 
95.—The Nest Biology of the Bee Andrenea 
(Ptilandrena) erigeniae Robertson (Hy) 
menoptera: Andrenidae). By Lloyd Rt 
Davis, Jr. and Wallace E. LaBerge. June 
1975. 16 p. 
CIRCULAR 


51.—Illinois Trees: Selection, Planting, and 
Care. By J. Cedric Carter. August, 1966) 
123 p. 

52.—Fertilizing and Watering Trees. By Dan 
Neely and E. B. Himelick. December, 1971! 
(Third printing.) 20 p. 

54.—Corn Rootworm Pest Management ini 
Canning Sweet Corn. By W. H. Luckmann,) 
J. T. Shaw, D. E. Kuhlman, R. Randell) 
and C. D. LeSar. March, 1975. 10 p. 


List of available publications mailed on request | 


| 

No charge is made for publications of the ILLiIvois NaTuRAL History Survey. A single: 

copy of most publications will be sent free to anyone requesting it until the supply becomes 

low. Costly publications, more than one copy of a publication, and publications in short supply: 

are subjects for special correspondence. Such correspondence should identify the writer and 
explain the use to be made of the publication or publications. 


Address orders and correspondence to the Chief, 
Illinois Natural History Survey 
Natural Resources Building, Urbana, Illinois 61801 


ra! 


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RL a my en iy eel fa eae 
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{ e h ' k a. A : 4 ve af 
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MAY 95 


UNIVERSITY OF ILLINOIS-URBANA 


| 


HN 


3 0112 018415429 


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