CAUTION

Pesticides used improperly can be injurious to humans, animals, and plants. Follow the

directions and heed all precautions on the labels.

Store pesticides in original containers under lock and key- out of the reach of children

and animal-and away from food and feed.

Apply pesticides so that they do not endanger humans, livestock, crops, beneficial

insects, fish, and wildlife. Do not apply pesticides when there is danger of drift, when

honeybees or other pollinating insects are visiting plants, or in ways that may contaminate

water or leave illegal residues.

Avoid prolonged inhalation of pesticide sprays or dusts; wear protective clothing and

equipment if specified on the container.

If your hands become contaminated with a pesticide, do not eat or drink until you have

washed. In case a pesticide is swallowed or gets in the eyes, follow the hrst-aid treatment

given on the label, and get prompt medical attention. If a pesticide is spilled on your skin

or clothing, remove clothing immediately and wash skin thoroughly.

Do not clean spray equipment or dump excess spray materials near ponds, streams, or

wells. Because it is difficult to remove all traces of herbicide from equipment, do not use the

same equipment for insecticides or fungicides that you use for herbicides.

Dispose of empty pesticide containers promptly. Have them buried in an approved

sanitary landfill.

NOTE: Some States have restrictions on the use of certain pesticides. Check your State

and local regulations. Also, because registrations of pesticides are under constant review

by the Federal Environmental Protection Agency, consult your county agricultural agent

or State extension specialist to ensure the product is still registered for use.

April 1999

Southern Research Station

P.O. Box 2680

Asheville, NC 28802
CONTENTS

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

FOLIAGE INSECTS . . . . . . . . . . . . . . Sycamore Tussock Moth . . . . . . . . Whitemarked Tussock Moth . . . . . Fall Webworm . . . . . . . . . . . . .

Leaffolders and Webworms . . . . . Case-Bearing Leaf Beetle . . . . . . . Sycamore Lace Bug . . . . . . . . .

Leafhoppers . . . . . . . . . . . . . . . . . MINOR FOLIAGE INSECTS . . . . Sycamore Leafblotch Miner . . . . . Drab Prominent . . . . . . . . . . . . . . . .

Japanese Beetle . . . . . . . . . . . . . . . . Sycamore Plant Bug . . . . . . . . . . . .

SEEDLING, TERMINAL, AND BRANCH INSECTS

Planthoppers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Scale Insects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Stalk Borer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

European Corn Borer . . . . . . . . . . . . . . . . . . . . . . . . . .

TRUNK BORERS . . . . . . . . . . . .

Columbian Timber Beetle . . . .

Flatheaded Borers . . . . . . . . . .

MINOR TRUNK BORERS . . . . .

Ambrosia Beetles . . . . . . . . . . . .

American Plum Borer . . . . . . . .

ROOT INSECTS . . . . . . . . . . . . .

Whitefringed Beetles . . . . . . . . .

SEEDLING DISEASES . . . . . . . .

Cylindrocladium Root Rot . . . .

FOLIAGE DISEASES . . . . . . . . . .

Anthracnose-LeafBlight . . . . . .

Powdery Mildews . . . . . . . . . . .

Bacterial Leaf Scorch . . . . . . . . .

Minor Leaf Spots and Blights . .

WILT, DECLINE, AND DIEBACK

Acremonium Wilt . . . . . . . . . . . .

Sycamore Decline and Dieback . .

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. 9

10

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. . . . 2.5

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. . . . 26
CANKERS ............................................ 28

Canker Stain ........................................ 28

Botryosphaeria Canker ................................ 30

Anthracnose-Twig Canker and Shoot Blight ............... 31

Hypoxylon Canker ................................... 32

Miscellaneous Cankers ................................ 33

ROOT AND BUTT ROTS .............................. 34

Armillaria Root Rot .................................. 34

Hericium Butt Rot ................................... 35

Oxyporus Root Rot ................................... 36

Ganoderma Butt Rot .................................. 37

Scytinostroma Root Rot ............................... 38

PARASITIC PLANTS .................................. 39

Mistletoe ........................................... 39

AIR POLLUTION AND CHEMICAL INJURIBS . . . . . . . . . . . . 40

MAINTAINING TREE HEALTH . . . . . . . . . . . . . . . . . . . . . . . . . 41

ACKNOWLEDGMENTS ................................ 43

GLOSSARY ........................................... 44

ii
A Guide to Major Insects, Diseases,

Air Pollution Injury, and Chemical

Injury of Sycamore

T.D. Leininger, J.D. Solomon,

A.D. Wilson, and N.M. Schiff

Abstract

This booklet will help nurserymen, forest woodland managers, pest control

operators, and homeowners to identify and control pest problems on sycamore

trees. The major insect and disease pests of sycamores in the Eastern United States

are emphasized. Descriptions and illustrations of the pests and the damage they

cause are provided to aid in identification. Brief notes are given on biology and

control to aid in predicting damage and making control decisions.

Keywords: Bacteria, biology, borers, control, defoliators, fungi, identification,

Platanus.

INTRODUCTION

Sycamore (Platanus occidentalis Mexico and southern Ontario. SyL.) is a common tree and one of the camore is often a pioneer species on

largest in eastern deciduous forests. river fronts, upland old-field sites, and

Other names are American sycamore, on strip-mined coal lands. However,

American planetree, buttonwood, and it grows best and biggest on sandy

buttonball-tree. Its native range in- loam soils with a good ground water

eludes the area east of the Great Plains supply, typically on alluvial sites

from south-central Texas and eastern along rivers and in bottomlands. SyNebraska eastward to Maine and camore timber is valued for both lumFlorida. However, sycamore is ber and pulp and is also planted

planted as an ornamental in many widely as a shade tree because of its

Western States, especially California. broad, dense crown, exfoliating bark

It is also found in northeastern on mature stems, and distinctive thin,

T.D. Leininger and A.D. Wilson are the Principal Research Plant Pathologists, J.D. Solomon is the Principal Research Entomologist, Emeritus, and N.M. Schiff is a Research Entomologist at the Southern

Hardwoods Laboratory, U.S. Department of Agriculture, Forest Service, Southern Research Station,

Stoneville, MS 38776; in cooperation with: Mississippi Agricultural and Forestry Experiment Station

and the Southern Hardwood Forest Research Group.
green to greenish-white bark on scaffold branches and young stems. Easily propagated from seeds or cuttings,

and second only to cottonwood in

growth rate, sycamore lends itself

well to artificial regeneration and intensive culture. It is among only a few

hardwood species used to establish

commercial plantations, an effort that

typically requires intensive site preparation, early weed control (cultivation

or herbicides or both), fertilization,

and, in some cases, irrigation. Some

plantations have been established at

very close spacing and are being regenerated from coppice on short rotations to maximize fiber production.

This kind of culture has been termed

“short-rotation forestry,” “silvicultural biomass farming,” or “fiber

farming.”

Insects, diseases, pollutants, and

chemicals present continuous threats

to sycamore growth and production.

Many insects feed on sycamore, but

few actually cause serious injury. Terminal-feeding insects can sometimes

cause serious seedling mortality and

misshaped stem form. Insect defoliators, perhaps the most common pests,

may strip entire trees or stands in localized areas, weakening trees and

causing growth loss. However, those

pests seldom cause significant mortality. Insect borers rarely occur in

large populations except in stressed

or weakened trees and in transplanted

ornamentals. Timber beetles sometimes seriously degrade sawtimber

and sawlogs.

Sycamore production usually suffers more from diseases than from

insects. In some years, leaf diseases

can defoliate trees or entire stands,

reducing radial and terminal growth

and weakening trees, making them

susceptible to other pathogens and

insect pests. Canker diseases, the most

damaging type of sycamore diseases,

can cause branch dieback, top dieback, and bole cankers. Dieback and

mortality caused by canker diseases,

along with other factors, have been

so serious in some plantations that a

few timber companies in parts of the

South have sycamore planting “on

hold” until disease-control methods

can be developed.

Cultural practices that maintain

and promote tree health help minimize losses caused by pathogens and

insects. It is better to prevent attack

by pathogens and insects than to remedy the aftermath of an attack. Some

recommendations are provided in the

back of this guide under “Maintaining Tree Health.” Chemical or other

direct controls may be needed as a last

resort.

This guide will help nursery

workers, forest managers, insect-pest

and disease-control specialists, and

homeowners to identify and control

insect pests and diseases of sycamore

trees. It emphasizes major diseases

and insect pests in the Eastern United

States and includes descriptions and

illustrations of pathogens and insects,

as well as the damage they cause. To

aid in assessing the risk of further

2
damage and making control decisions,

brief notes describe the biology and

control of pathogens and insects.

We have described pathogens and

insects both with common names and

Latin binomials, including taxonomic

authorities. However, a distinction

must be made between the treatment

of disease and pathogen nomenclature

and that of insects. The common

name of an insect refers to the insect

itself. The common name of a disease

typically includes the latin name for

the genus of the pathogen causing the

disease. For example, the fungal

pathogen Cylindrocladium scoparium

causes the disease Cylindrocladium

root rot. For simplicity, we have omitted the words “caused by” between

each disease name and its respective

pathogen name.

Specific chemical controls are not

listed because recommendations

change whenever compounds are discontinued or new materials are approved. For information on pesticides

or additional assistance with managing sycamore pests, the landowner

should contact his or her county extension agent, State Forester, or the

nearest office of the U.S. Department

of Agriculture, Forest Service, State

and Private Forestry, Forest Health

Protection.

3
FOLIAGE INSECTS

Sycamore Tussock Moth, Walsh

Importance.-This insect feeds on

sycamore leaves throughout the Eastern

United States. It is more likely to defoliate older plantations, seed orchards, and

ornamental plantings than nurseries and

young plantations. Repeated late-summer

defoliation reduces growth and vigor.

Identifying the Insect (fig. la, b).-

Larvae have orangish heads and yellowish bodies covered with hair. Caterpillars

(30 mm long) exhibit long hair pencilstwo pairs of orange and 2 pairs of white

hair pencils anteriorly, and one pair of

white hair pencils posteriorly. Moths are

pale yellow with darker bands on forewings.

Identifying the Injury (fig. lc).-

Young larvae skeletonize the leaves, feeding together on the leaf’s underside. Older

larvae devour all but the major leaf veins.

Biology.-Moths emerge from overwintering cocoons during May and June

and deposit egg masses on the underside

of leaves and on bark. Eggs hatch in late

May and June. Young larvae feed close

together; older larvae scatter and become

solitary feeders. Pupation occurs in late

June and July in hairy, ball-like cocoons

on bark and nearby debris. Moths emerge

in July and August to produce a second

generation. These larvae spin cocoons and

pupate in late September and October to

overwinter.

Control.-Natural enemies control

most populations. The control of brush

and debris in and around plantings will

reduce the best pupation sites. Chemical

controls may be needed.

Figure l-(a) Sycamore tussock moth, (b) larva and feeding injury; (c) young plantation sycamore

defoliated.
Whitemarked ‘lbssock Moth, Orgyia leucostigma (J. E. Smith)

Importance.-This tussock moth defoliates a wide variety of trees, but the

sycamore is among its preferred hosts. It

occurs throughout the Eastern United

States and Southern Canada. Heavy defoliation causes growth loss and dieback

but rarely kills trees.

Identifying the Insect (fig. 2a, b).-

The yellowish, hairy larva (30 mm long)

has a coral-red head and thoracic shield

with a black dorsal stripe. Four yellowish, brushlike hair tufts occur dorsally. A

pair of black hair pencils arises anteriorly,

and a single hair pencil arises posteriorly.

Male moths are gray with dark wavy

bands on the forewings. Females have no

wings. Eggs are deposited in flattened

clusters covered with whitish, frothy material.

Identifying the Injury (fig. 2c).-

Young larvae skeletonize the undersides

of leaves. Older larvae disperse and

consume leaf patches, eventually

consuming all but the leaf’s midrib and

main veins. Late-summer defoliation by

large populations may cause a

skeletonlike appearance to entire trees as

well as entire stands.

Biology. - Overwintering eggs hatch

from April to June. Newly hatched larvae feed close together but often are dispersed on silken threads by wind. Larvae mature in 5 to 7 weeks and spin grayish, hairy cocoons on the underside of

branches and in bark crevices. The pupal stage lasts 2 weeks. Females deposit

50 to 300 eggs in masses usually on or

near the old cocoons. There are one to

three generations per year. Egg masses

overwinter on host plants.

Control.-Populations on small trees

can be controlled by destroying the conspicuous, whitish egg masses. Insecticides may be needed.

Figure 2-(a) Wingless female whitemarked tassock moth laying a mass of eggs; (b) larvae and

feeding injury; (c) young trees defoliated.
Fall Webworm, Hyphantriu culzea (Drury)

Importance.-The fall webworm defoliates more than 100 deciduous tree species across the United States and Southem Canada. Although seldom entirely defoliated, infested sycamore trees may be

severely “ragged” causing premature leaf

drop and reduced growth and vigor.

Identifying the Insect (fig. 3a, b).-

There are two races of H. cuneablackheaded and redheaded. Larvae of

both are pale yellowish with a broad,

dusky dorsal stripe and yellowish lateral

stripes. Covered with gray hair, the larvae are about 25 mm long. Moths are pure

white to white with small dark spots. The

tiny gray eggs are in large masses partially

covered with short grayish hairs.

Identifying the Injury (fig. 3c).-

Typically, large silken webs enclose one

or more leaves and, eventually, entire

branches in summer and fall. In sycamore

plantations, however, webbing is present,

but large tents may not be. Large groups

of feeding caterpillars can cause sparse

and ragged foliage over the entire crown.

Biology.-Moths emerge from overwintering pupae from March to July and

oviposit on the underside of leaves in

masses of 300 to 500 eggs, that hatch in

10 days. Distinct silken tents often do not

occur on sycamore trees. Larvae may be

present from April to October, but the

greatest numbers occur in late summer

and fall. Pupation occurs in thin cocoons

near the soil surface. There are one to

four generations per year, depending on

locale and race.

Control.-More than 80 natural enemies are known. For young trees, it is

possible to control the insect by clipping

and destroying the webbed branches while

the larvae are small. Insecticides may be

required.

Figure 3-(a) Fall webworm egg mass on underside of leaf, (b) larvae feeding under webbing; (c)

partially defoliated sycamore with little webbing.

6
Leaffolders and Webworms, Ancylis platanana (Clemens), Pococera militella

(Zeller), Adoxophyes jiucatana (walker)

Importance.-A complex of leaffolding and web-making larvae feed on

sycamore leaves. Ancylis platanana, occurring only on Platanus throughout the

Eastern United States, is emphasized

here. Heavy defoliation of small groups

of trees may occur. Repeated defoliation

may reduce growth and incite crown dieback.

Identifying the Insect (fig. 4a).-

Larvae of A. platanana are slender and

pale yellow with smooth bodies; mature

larvae are 9 to 11 mm long. The forewings of adults are reddish with white

markings. Eggs are small, oval, and almost colorless.

Identifying the Injury (fig. 4b, c>.-

Small, silken shelters are found on the

undersurface of partially skeletonized

leaves. A leaf gradually becomes folded

and is further webbed and skeletonized,

often leaving only a brown network of the

larger veins. Injury by other webworms

is similar but with more extensive webbing.

Biology.-Adults of A. platanana

emerge from March to May and deposit

eggs singly on the undersides of leaves.

Eggs hatch in 3 to 5 days, and the young

larvae feed along the leaf midrib. Older

larvae pull the leaf over into a fold and

feed for about 6 weeks until they pupate

beneath the webbing in the folded leaf.

The pupal stage lasts 9 to 11 days before

the adults emerge. There are three to four

generations per year. Overwintering occurs as prepupae in fallen leaves.

Control.-Natural enemies help control populations. Some control is possible

by disking to bury fallen leaves and pupae.

Figure 4-(a) Leaffolder larvae and early-season feeding at base of leaf; (b) advanced feeding and

extensive webbing; (c) heavy defoliation.
Case-Bearing Leaf Beetle, Neochlumisus platani (Brown)

Importance.-This beetle is known

from Massachusetts west to Colorado and

south to Florida and Texas. It feeds on

sycamore foliage and prefers young trees.

Defoliation may result in loss of growth

and aesthetic value, but no crown dieback

or mortality has been associated with this

insect.

Identifying the Insect (fig. 5a, b).-

Adults are peculiarly shaped leaf beetles

with a rough, knobby, brownish body surface, 4 to 5 mm long, resembling the

brown excrement pellets of large caterpillars. When disturbed, beetles feign

death and fall from the plants. Larvae are

white with black heads and legs, 5.4 to

6.5 mm long, and live in dark-brown

cases made of fecal excreta, which conceal all but the head and legs.

Identifying the Injury (fig. 5c, d).-

Both adult beetles and case-bearing

larvae are found feeding on young foliage.

Small, scattered holes appear in the leaf.

In time, the holes are enlarged and,

typically, uniformly distributed over the

leaf surface. Trees may appear “ragged”

from heavy leaf feeding but are seldom

completely defoliated.

Biology.-Overwintering beetles appear on the foliage of host trees in April

and May. Females lay tiny, bell-shaped,

excrement-covered eggs singly and on

short stalks on the undersides of leaves.

Young larvae construct and live within

cases made of their own frass. Pupation

occurs within the case attached to the underside of a leaf. Highest populations occur in early summer. Only one or two generations occur per year.

Control.-Parasites and predators

usually keep populations under control.

Figure 5-(a) Larval case; (b) larva removed from case; (c) close-up of feeding damage; (d) tree with

feeding injury.

8
Sycamore Lace Bug, Cqthucha ciliatu (Say)

Importance.--One of the most common insects found on sycamore foliage,

lace bugs may occur in large numbers on

shade or ornamental trees in urban areas,

especially in late summer or during dry

periods. Corythucha ciliata is a problem

throughout the Eastern United States.

Identifying the Insect (fig. 6a, b).-

The adult is a pale, flattened insect about

3 mm long whose wing covers are extended and so intricately ornamented that

they appear to be made of a piece of lace.

Immatures are also flattened but are black

and covered with spines.

Identifying the Injury.-The lace

bug pierces the epidermis and withdraws

fluids and cell contents, which results in

chlorotic flecking on the upper surface of

leaves. Late in the growing season the

leaf’s lower surfaces may appear messy,

having been varnished with lacebug

excrement and shed skins. Large

populations of lace bugs may cause leaves

to turn brown and drop prematurely.

Biology.-Adults overwinter under

bark and become active when leaves start

to develop. Eggs are glued to the pubescence on the undersides of leaves. Both

adults and nymphs feed on the undersides

of leaves by sucking sap with piercing

mouthparts. Nymphs seldom move to another leaf until they are almost mature.

The complete life cycle from egg to adult

takes about 30 days, and there may be 2

to 5 or more generations per year. Late in

the year, synchrony of generations breaks

down, and all life stages may be found on

the same leaves.

Control.-Predators usually keep

lace bug populations small. Chemical

control may be required in late summer

and fall when populations are largest.

Figure 6-(a) Adult lace bugs feeding on underside of leaf; (b) lace bug nymphs feeding on underside

of leaf.

9
Leafhoppers, Erythroneura Zawsoni Robinson, E. arta Olivier, E. usitata Beamer

Importance.-Although many species of leafhoppers may be found on sycamore foliage, the three listed species of

Erythroneura cause most infestations.

Leafhoppers suck the leaf sap, reducing

tree vigor, and may transmit viruses and

mycoplasma diseases.

Identifying the Insect (fig. 7a).-

Leafhopper adults are small (6 mm), linear insects that appear tapered at both

ends. They vary from yellowish to light

green with some speckling or striping.

Leafhoppers jump or shoot away when

disturbed, earning them the nickname

sharpshooters. Immatures have a similar

shape but are smaller, wingless, and paler

in color with the ability to run backwards

on the leaf.

Identifying the Injury (fig. 7b).-

Injured leaves become stippled and

chlorotic, especially around the midrib

and basal veins. Large populations of

leafhoppers may be present on the

undersides of leaves. Heavy infestations

result in poor leaf color, premature leaf

drop, and a less pleasing appearance.

Biology.-After overwintering in leaf

litter and debris, adult leafhoppers become active on newly opened sycamore

buds. Mating and egg laying start early in

the growing season. An average generation matures in 41 days. In the late fall,

adults move to protected sites to overwinter.

Control.-Leafhoppers are controlled

by spiders, wasps, fungal diseases, and

abiotic factors such as rainfall and wind.

Chemical control may be needed for

ornamental trees during summer and

fall.

Figure 7-(a) Leafhopper adults feeding on underside of leaf: (b) chlorotic stippling from feeding

injury (top leaf), healthy leaf (bottom).

10
MINOR FOLIAGE INSECTS

Sycamore Leafhlotch Miner, Ectoedemiu plutunellu (Clemens)

Leafblotch miner larvae are pale green,

slightly flattened with a retracted head,

up to 4 mm long, living singly within distinct leaf mines. The tiny adult moth is

seldom seen, but it ranges over much of

the Eastern United States. Ectoedemia

leaf injury appears as a brown, circular

blotch mine (+ 1 cm diameter) just below

the leaf cuticle. Mines originate from a

narrow entrance mine and are filled with

frass in the center (fig. 8). Heavily mined

leaves drop prematurely. Injury is unsightly, but its impact on tree health usually is slight to negligible. Natural enemies control most populations. Direct

controls are rarely needed. Figure 8Sycamore leaf with brown mines of

E. platanella.

Drab Prominent, Misogadu unicolor (Packard)

Drab prominent larvae are light green with

a broad, yellowish-white dorsal stripe

(with brownish patches) and narrow indistinct lines on each side. A pair of taillike projections is borne on the last abdominal segment. Mature larvae are 30

to 42 mm long (fig. 9) and may be present

from April to September. Young larvae

feed close together and skeletonize the

undersides of leaves. Large larvae become solitary feeders and will devour all

but a leaf’s major veins. There are two to

three generations per year. Parasites keep

most populations in check.

Figure 9-Fully grown larva of 44. unicolor.
Japanese Beetle, Popillia japonica Newman

Japanese beetles are broadly oval, 12 mm

long, metallic green and coppery, with

small tufts of white hair both behind and

on each side of the elytra (fig. 10). Prevalent in some Atlantic Coast States, they

emerge from May to July and live for 30

to 45 days. They feed on over 300 plant

species and devour sycamore leaf tissue

between the veins, commonly leaving

only a lacelike network of veins. They

may completely defoliate seedlings and

young trees. A milky disease bacterium,

Bacilluspopilliae Dutky, is commercially

available to control the larval stage in the

soil. Chemical control of adults may be

needed. Figure l&Japanese beetle (inset) and feeding

injury to leaves.

Sycamore Plant Bug, Plagiognathus albatus (Van Duzee)

Adults are pale yellowish, elongated softbodied true bugs, 3 to 5 mm long, with

piercing-sucking mouthparts (fig. 11).

Nymphs resemble the adults but are wingless. These bugs occur over much of Eastem North America. Overwintering eggs,

embedded in twig tissue below leaf buds,

hatch in April. Nymphs and adults (both

present until July) feed on tender leaves,

causing tiny irregular brown spots that

often fall out, leaving a ragged and tattered leaf (fig. 11). There is one generation per year. Direct controls may be

needed to protect high-value trees.

Figure 1 l-Adult of P. albatus (inset) and injury

to foliage.

12
SEEDLING, TERMINAL, AND BRANCH INSECTS

Planthoppers, Ormenoides venusta (Melichar), Anormenis septentrionalis (Spinola)

Importance.-Planthoppers feed on

sycamore and many other species

throughout the Eastern United States and

as far West as Texas and Arizona. Their

sap feeding and oviposition injuries sometimes cause serious damage to seedlings

and the terminals of older plants.

Identifying the Insects (fig. 12a).-

Adults are snow white to pale green and

have large prominent wings held at an

acute, rooflike angle over the body. They

range from 6 to 12 mm long. Nymphs are

white or greenish, wingless, slightly flattened with abdomen curved slightly upward, and are partially covered with filaments of white, wool-like wax.

Identifying the Injury (fig. 12b).-

Sap feeding by large populations may

cause succulent shoots to wilt and grow

more slowly but seldom causes dieback.

However, large clusters of oviposition

punctures along the stems may cause seedling mortality as well as terminal dieback

in older plants. Young seedlings planted

adjacent to natural stands are most prone

to injury.

Biology.-Eggs overwinter inside

twigs of host plants and hatch in the

spring. The nymphs feed in clusters on

succulent shoots. Adults begin appearing

in June and are present until fall. Females

deposit their eggs in short slits in the bark

of the current year’s growth. There is one

generation per year.

Control.-Shoots containing clusters

of oviposition punctures can be pruned

and destroyed in fall and winter, although

natural enemies keep most populations in

check.

Figure 12-(a) Planthopper adults feeding on a young sycamore stem; (b) a young sycamore terminal

killed by punctures of egg-laying adults.

13
Scale Insects, Terrapin scale, Mesokcanium nigrufusciutum (Pergande); Cottony

maple scale, Puluinariu innumerubilis (Rathvon); European fruit lecanium,

Parthenolecanium corni (Boucht); Oystershell scale, Lepidosuphes ulmi (L.)

Importance.-Scale insects reduce

plant vigor and may cause faded areas in

affected leaves, premature leaf drop, and

even twig mortality. They produce honeydew, which supports the growth of

sooty molds that block photosynthesis.

Injuries detract from the appearance and

value of the tree. These insects occur

throughout the United States.

Identifying the Insect. -Terrapin

scale females appear as oval-shaped, reddish-brown, shiny bumps (2 mm across)

on branches (fig. 13a). Cottony maple

scale females look like small powdery

popcorn kernels with a dark shell (4 to 6

mm) trailing a large cottony white egg sac

(fig. 13b). European fruit lecanium females are distinctly humped (3 to 6 mm),

dark brown to reddish, and sometimes

covered with whitish powder (fig. 13~).

Oystershell scale females look like tiny

(3 mm long), chestnut-brown oyster

shells. In large numbers they form a

“crust” on trunks and branches.

Identifying the Injury.-Injury may

appear as yellow spots on leaves, necrotic

areas, dieback, shiny leaves, growth of

black sooty mold, or leaf drop. Scales can

be found by examining the bark.

Biology.-Scale insect life cycles are

complicated with large, somewhat sedentary females and relatively small, winged

males. There may be several generations

per year. Overwintering is typically on

branches or under bark.

Control.-Parasites and predators

usually keep scales under control. Occasional chemical treatment of ornamental

plants may be useful.

Figure 13-(a) Terrapin scale; (b: I cottony maple scale; (c) European fruit lecanium.
Stalk Borer, Papaipema nebris (Guenee)

Importance.-The stalk borer is

widely distributed throughout the Eastern

United States and Canada. It attacks over

175 herbaceous and woody plant species.

Corn, grasses, and giant ragweed are favored hosts. However, succulent sycamore shoots are killed occasionally in

nurseries and young plantations.

Identifying the Insect (fig. 14a, b).-

Larvae have broad stripes of pale white

and brown interrupted by a distinct band

of purplish brown around the third thoracic and first abdominal segments. Mature larvae are 25 to 32 mm long. Adults

are robust moths; their forewings are purplish brown with several small white

spots. Eggs are globular and whitish

brown.

Identifying the Injury (fig. 14c).-

Sudden wilting and flagging of succulent

shoots with 3-mm-diameter round

entrance holes occur in late spring.

Excrement pellets often are present at

entrance holes. Opening the shoot will

reveal a tunnel and larva.

Biology.-Overwintering eggs hatch

from April to June. Young larvae feed on

grasses; older larvae seek larger, succulent stems and often migrate from herbaceous plants to young sycamore trees.

Larval development varies from 60 to 130

days. Mature larvae abandon their hosts

and pupate just below the soil surface.

Moths emerge from August to October

and deposit up to 2,000 eggs each on

grasses where they overwinter. There is

one generation per year.

Control.-Damage can be minimized

by disking weedy borders of nurseries and

young plantations to destroy breeding

sites in early August. Direct controls may

be needed.

Figure 14--(a) Stalk borer adult; (b) larva tunneling in young shoot; (c) terminal being killed by larval

tunneling, gallery entrance near apex.
European Corn Borer, Ostriniu nubildis (Htibner)

Importance.-This pest of corn and

over 100 other plants sometimes infests

sycamore trees in the Eastern United

States. Typically, trees are attacked only

when growing near heavily infested preferred hosts such as corn and certain cover

crops. In sycamore nurseries, the European corn borer may tunnel through and

kill up to 30 percent of the terminals.

Identifying the Insect (fig. 15a).-

Larvae have brownish mottled heads and

grayish bodies with pinkish-brown stripes

and are about 25 mm long. Adult moths

are brownish with yellowish-brown

forewings that are somewhat streaked.

Eggs are oval and yellowish white.

Identifying the Injury (fig. 15b,c).-

The first sign of infestation is rapid wilting and dying of seedling terminals and

branch tips. Holes 4 to 6 mm in diameter

are found in tender shoots. Splitting the

infested shoot will reveal a tunnel, frass,

and a gray larva.

Biology.-Overwintering larvae pupate in April and May, and moths emerge

from May to June. Females deposit 500

to 600 eggs on herbaceous hosts that hatch

in a week. Larvae complete feeding in

July, and moths emerge in August. Second generation larvae feed until fall and

overwinter in their tunnels. There may be

one to two generations per year. Infestation of sycamore tree typically occurs

when heavily infested herbaceous hosts

mature or are harvested, causing the larvae to migrate to other succulent hosts.

Control.-Preferred crops like corn

or millet should not be planted next to

sycamore nurseries. Chemical controls

may be required.

Figure 15--(a) Larvae of 0. nubildis; (b) terminal being killed by larval tunneling; (c) young stems

with entrance holes, frass, and tunnel.

16
TRUNK BORERS

Colombian Timber Beetle, Corthylus columbianus Hopkins

Importance.-The Columbian timber

beetle occurs from Massachusetts south

to Florida and west to Kansas. Beetles

bore into the trunks of trees of all sizes.

Beetle attacks do not seem to affect tree

health directly, but they provide entry

points for canker and other diseases. Damage can degrade the lumber by as much

as 25 percent.

Identifying the Insect (fig. 16a).-

Adults are 3.6 to 4.0 mm long, reddish

brown to black, cylindrical ambrosia

beetles. Eggs are white, translucent, shiny,

and oval. Larvae are white, legless, Cshaped, and about 4 mm long.

Identifying the Injury (fig. 16b, c).-

Sap and fine frass oozing out of small

round entrance holes in the trunk are evidence of injury. Radiating brown stains

in log ends are evidence of damage in

sawlogs. In lumber and veneer, defects

consist of small, black, round holes surrounded by elongated brown stains.

Biology.-Adults overwinter in bark

niches around the base of host trees.

Beetles emerge in May and June and begin excavating brood galleries on host

trees. Completed galleries consist of primary, secondary, and tertiary channels

with 1 to 20 brood cells (cradles). Eggs

are deposited singly in each brood cell.

Both larvae and adults feed on ambrosia

fungi that grow on gallery walls. Brood

emergence occurs in 6 to 7 weeks. There

are two to three generations per year.

Control.-Few natural enemies have

been identified, and no direct controls

have been developed.

Figure l&-(a) Adult of C. columbianus; (b) tiny entrance hole with frass and stain; (c) stained

flagworm defects in lumber.
Flatheaded Borers, Flatheaded appletree borer, Chrysobothris femorata (Olivier);

Pacific flatheaded borer, C. maZi (Horn)

Importance.-These borers are

widely distributed: C. femorata, throughout the United States into Canada and

Mexico; and C. mali, through the Westem States. They make extensive galleries

under the bark and often girdle and kill

newly transplanted trees.

Identifying the Insects (fig. 17a,

b).-Larvae are yellowish white, legless,

and 18 to 25 mm long. The thoracic segments are broadened, which gives the

appearance of large, flat heads. Adults are

flattened, metallic-hued beetles (7 to 16

mm long), marked with gray spots in C.

femorata and coppery spots in C. mali.

Eggs are yellowish white, flattened and

disclike.

Identifying the Injury (fig. 17c).-

White, frothy sap oozes from cracks in

the bark. Tunnels under the bark are

broad, irregular, and packed with powdery

frass. The bark of infested trees may be

heavily scarred by larval burrows and

oval exit holes of emerging beetles.

Biology.-Adults begin emerging in

March and are present until fall. Females

deposit about 100 eggs each in small

groups in bark crevices. Eggs hatch in 8

to 16 days. Larvae feed in the cambium

until late summer, then tunnel radially into

the sapwood to overwinter. In spring, the

larvae pupate for 8 to 14 days before the

adults emerge. Generation time varies

from 1 to 2 years.

Control.-Cultural practices that promote tree vigor help minimize attacks.

Weakened and dying trees should be removed to eliminate breeding sites.

Figure 17-(a) Adult of C. femoruta; (b) bark removed to expose larva; (c) larval burrow in bark.

18
MINOR TRUNK BORERS

Ambrosia Beetles, Xylosandrus spp., Xyleborus spp., Platypus spp.

Some ambrosia beetles attack healthy

trees, but most prefer weakened, injured,

or dying trees and fresh-cut logs (fig. 18).

They bore into the sapwood and reduce

tree and log values for wood products;

some spread fungal pathogens. Larvae

feed on a moldy fungus called ambrosia

that adult females culture on the gallery

walls. Small piles of boring dust or strings

of compacted frass may be present on the

bark. There are two or more generations

per year. Adults can be trapped with

pheromones. Logs should be processed

promptly.

Figure 18-Adult of l? compositus (inset) and

strings of frass.

American Plum Borer, Euzophera semifuneralis (Walker)

Larvae vary from dark pink or reddish

gray to dusky green, with a dark-brown

head and thoracic shield. They are about

25 mm long when full grown (fig. 19).

The American plum borer is widely distributed throughout the United States,

Canada, and parts of Mexico. Weepy sap

spots appear on the bark, followed by

accumulations of reddish frass in bark

crevices (fig. 19). Lifting the bark will

expose larval burrows, frass, larvae, and

white, silken cocoons. This borer prefers

trees in poor health, especially those with

mechanical injuries to the bark and canker diseases. Good cultural practices help

minimize infestation. Direct controls may

be needed to protect valuable trees.

Figure 19-Larva of E. semifunerulis (inset),

frass, and burrows.
ROOT INSECTS

Whitefringed Beetles, (Boheman), G. minor

(Buchanan), G. peregrinus (Buchanan), and G. fecundus Buchanan

Importance.-Whitefringed beetles

were introduced into Florida in 1936 and

have spread north to Virginia and west to

Louisiana. They feed on over 300 plant

species. On young sycamore trees, the

larvae destroy both tap and lateral roots.

Damage may occur in new nurseries and

first-year plantations established on sites

with heavier soils not well suited for sycamore production.

Identifying the Insects (fig. 20a,

b).-Adults are dark-gray, 9-mm-long

beetles with a white fringe along the outer

margins. Full-grown larvae are yellowish

white, C-shaped, legless, and 12 mm long

with a pale head. Eggs are oval and pale

yellow.

Identifying the Injury. (fig. 2Oc).-

Damaged plants become chlorotic and

may die; injured survivors appear yellow

and unhealthy. Excavation will reveal root

injury. Larvae can be found in the top 12

to 24 cm of soil. Adults may be seen resting around the bases of plants.

Biology.-Overwintering larvae begin pupating in April, and adults emerge

from May to October. All adults are females, each of which deposits up to 1,500

eggs in the soil in masses of 11 to 14. Eggs

hatch in 11 to 30 days, and larvae feed on

plant roots. There is one generation per

year. Adults cannot fly, but the insect is

easily spread by moving infested plants,

soil, or equipment.

Control.-Commercial traps are

available to monitor infestations. Fallowing heavily infested soils will reduce

populations.

Figure 2&(a) Whitefringed beetle; (b) larvae; (c) larval feeding injury to roots of sycamore seedling.
SEEDLING DISEASES

Cylindrocladium Root Rot, Morg.

Importance.-Sycamore seedlings

and other southern hardwood species are

susceptible to Cylindrocladium root rot,

especially in nurseries where seedlings are

grown close together (fig. 21a).

Identifying the Disease.-Infected

seedlings may be killed by this disease or

will exhibit a combination of symptoms:

damping-off, root rot, hypocotyl rot, leaf

spots, leaf blight, stem lesions, twig dieback, and wilting. Affected roots turn

black, shrivel, and die (fig. 21b).

Aboveground symptoms are favored by

warm, moist conditions such as those that

exist during summer irrigation by overhead sprinklers.

Identifying the Fungus.-The fungus produces pinpoint-sized, brown

microsclerotia on dead roots, leaves, and

stem lesions. Tiny white tufts of conidia

appear on surface lesions. Yellow-orange

perithecia (0.4 mm) may form on dead

leaves and bark under moist conditions.

Biology.--Conidia produced on stem

and leaf lesions are spread by wind and

splashing rain to other susceptible seedlings. Microsclerotia released into the soil

may survive for years, and, during moist

conditions, germinate to infect roots.

Control.-To prevent spread of inoculum and minimize conditions that favor the fungus, avoid overhead watering

in the summer. Plant seedlings further

apart to promote vigorous growth and reduce seedling susceptibility. Remove diseased seedlings, and improve soil drainage on moist sites. High-hazard sites may

require soil fumigation in the fall or spring

to reduce inoculum in the soil.

Figure 21-(a) Sycamore seedling

survival in the center and right

rows is poor due to root rot,

compared to that of the two rows

on the left.

(b) Sycamore seedlings with root

damage (left), and normal roots

(right).
FOLIAGE DISEASES

Anthracnose-Leaf Blight, Apiognomonia (=Gnomonia) veneta (Sacc. & Speg.)

H6hn.

Importance.-(See p. 31, Anthracnose-Twig Canker and Shoot Blight).

Identifying the Disease.-Anthracnose-blighted leaves have irregularly

shaped, tan necrotic patches that run along

the midrib and larger veins (fig. 22a).

Necrotic patches often coalesce and span

the area between veins. Lesions also form

on petioles and along leaf margins. Repeated infections throughout the growing

season can cause severe defoliation (fig.

22c).

Identifying the Fungus.-Colorless,

one-celled conidia are produced in pinhead-sized, cream-colored acervuli on the

bottoms of diseased leaves along veins

and the midrib.

Biology.--Conidia produced on fallen

leaves or on the bark of diseased twigs

germinate and infect new leaves as hyphae

grow along veins and the midrib into the

petiole and twig. Leaf infections are

favored by cool (16-20 “C), wet weather.

Repeated infections can occur throughout

the growing season under favorable

weather conditions, which, in the South,

are common in the fall.

Control.-Wet conditions favor foliar

infections. Sycamore in plantations may

be protected by increasing the space between rows to ensure air movement. Landscape trees may be protected from initial

infections by applying a contact fungicide

when buds begin to swell and, again, 10

to 14 days later. Injections of systemic

fungicides offer protection as well (fig.

22b). Disease resistant varieties should be

planted if possible. There is no practical

control for this disease in forests.

Figure 22-(a) Tan, necrotic patches along main veins of a leaf; (b) a systemic fungicide protected the

sycamore on the left for 3 years compared to the two trees on the right; (c) severe defoliation from a

heavy anthracnose infection.

22
Powdery Mildews, Microsphaera penicillata (Wallr.:Fr.) LCv. or Phyllactinia

guttata (Wallr.:Fr.) Lev.

Importance.-Powdery mildews are

common throughout the range of sycamore trees and are most damaging on

younger, smaller trees in ornamental, nursery, or orchard settings. They do not cause

significant damage in forests.

Identifying the Disease.-These

fungi are named for the powdery white or,

as they age, gray mycelia they produce on

upper and lower leaf surfaces (fig. 23a).

Infected leaves are often stunted, buckled, or cupped (fig. 23b). Mycelial mats

may entirely cover young leaves or may

occur as irregularly-shaped blotches (0.5

to several cm) on larger leaves.

Identifying the Fungi.-Young

mycelial mats will have only the conidial

stage of the fungus, which produces colorless spores. Older colonies may have

spherical, brown-black cleistothecia (0.1

to 0.2 mm) with distinctive appendages

that aid in identification. In warmer areas, cleistothecia may not form.

Biology-Initial infections are from

spores that overwintered on fallen leaves

or in buds. Infections begin on young

shoots and expanding leaves but rarely on

mature leaves. Conidia are spread on air

currents and can germinate on dry plant

surfaces. Disease buildup is favored by

warm, dry days and cool nights.

Control.-Because powdery mildews

grow superficially on leaves, they are easily controlled on ornamental trees with

organic contact fungicides or sulfur dust.

Disease occurrence may increase with

activities that stimulate or prolong the

occurrence of new growth; e.g., fertilizing and cultivating. Control in forests usually is not needed.

Figure 23-(a) White and gray mycelial mats of powdery mildew fungus on leaves in foreground;

uninfected leaves in background; (b) leaf distortion and cupping caused by powdery mildew.

23
Bacterial Leaf Scorch, Xylella fastidiosa Wells et al.

Importance.-Planted and wild

sycamores are probably affected

throughout the Southeast. Bacterial leaf

scorch has been found in plantation

sycamore in Virginia, Kentucky, Illinois,

Georgia, North Carolina, South Carolina,

and Alabama and in the wild in

Mississippi, Louisiana, and Texas. The

disease is becoming important as more is

learned about its pathogenicity and

distribution.

Identifying the Disease.-Olive-drab

leaves appear in midsummer. Leaves later

appear scorched as tissues along leaf margins and between veins turn brown (fig.

24a). Symptoms advance from older to

younger leaves on a branch; scorched

leaves curl upward and stay attached until

fall (fig. 24b). Leaf scorch appears first on

one branch, or a group of branches in one

part of the crown, and moves through the

crown in later years. Branch dieback may

be worsened by secondary infections of

such fungi as Botryosphaeria rhodina (p.

30). Bacterial leaf scorch may be mistaken for anthracnose (p. 22), which

mainly affects young leaves during cool,

wet periods. In some plantations, branch

dieback, progressive decline (p. 26), and

death occur within 5 to 7 years.

Identifying the Bacterium.-XyZeZZa

fastidiosa can be identified with a microscope. Otherwise, five to seven 2-cm-long

sections of symptomatic leaf petioles, from

three branches per suspect tree, can be

submitted to a State cooperative extension lab for an ELISA test to determine if

this bacterium is in the tissue.

Biology.-Xylella fastidiosa occurs

only in xylem tissue where it blocks water

conduction. The bacteria are transmitted

from plant to plant by xylem sap-feeding

insects such as treehoppers. Cold limits

bacterial growth, but leaf scorch seems to

be enhanced by hot, dry weather.

Control.-Xylella fastidiosa has a

wide host range, which makes it hard to

control directly by removing other hosts,

or, indirectly, by trying to control insect

vectors. Maintaining tree health by irrigating and fertilizing ornamental and plantation trees may delay disease onset and

prolong the life of infected trees.

Figure 24-(a) Variation in leaf scorching caused by the leaf scorch bacterium; (b) leaves look

scorched and cup upwards; older leaves are affected before younger leaves.

24
Minor Leaf Spots and Blights, Mycosphaerella platanifolia (Cooke) EA. Wolf,

M. stigmina-platani EA. Wolf, Septoria platanifolia Cooke in Revenel, and

Phloeospora multimaculans Heald & EA. Wolf

Importance.-Leaf-spotting fungi are

generally of little importance to tree

health. Severe infections that trigger early

leaf abscission may have some effect on

growth, but the main consequence is to

the tree’s appearance.

Identifying the Disease.-Mycosphaerella platanifolia and M. stigminaplatani leaf spots appear as unevenly

round, tan spots (0.1 to 1 cm) with redbrown halos that may coalesce into larger,

irregularly shaped lesions (fig. 25). Leaves

infected by P. multimaculans develop

unevenly round or angular, brown to

purple spots (1 to 3 mm). Septoria

platanifolia produces brown, circular

spots that later develop gray centers with

dark halos. Spots typically develop on the

upper surfaces of leaves. The lower surfaces of leaves infected by M. stigminaplatani may have a diffuse, sooty film.

Identifying the Fungi.-Ascospores

of both Mycosphaerella species are twocelled. The conidia of the Cercospora or

Stigmina stages are multiseptate. Pycnidia

of P. multimaculans grow on the lower

surfaces of leaves and produce colorless,

cylindrical, slightly curved conidia with

one to four’ septations.

Biology.-Initial infections of

Mycosphaerella, the sexual stage of the

first two fungi, occur in early spring from

spores produced in fruiting bodies on

fallen leaves. Subsequent infections occur as asexual conidia from the

Cercospora or Stigmina stages are moved

by wind or rain splashing. Conidia of S.

platanifolia and P multimaculans are

spread by wind and rain from pycnidia

that form on the leaf spots.

Control.-Leaf spots typically do not

warrant control on ornamental or forest

trees because they are of minor consequence to tree health However, organic

fungicides are sometimes used to control

severe outbreaks.

Figure 25-Mycosphaerella leaf spots.

25
WILT, DECLINE, AND DIEBACK

Acremonium Wilt, Acremonium

(=Cephalosporium) diospyri (Crandall)

W. Gams

Fungus.-Initial infections by

conidia likely occur through bark wounds

made by insects, animals, or storms.

Injury-Brown leaves appear on one

to several branches in spring. The disease

develops progressively causing twig dieback, defoliation, and pale-yellow, stunted

foliar regrowth (fig. 26). Acremonium wilt

is favored by hot weather (2 30 “C). Wilted

sycamores are susceptible to infection by

B. rhodina (p. 30).

Control.-Acremonium wilt is

mainly a problem in urban areas of east

Texas. It has been controlled experimentally by spraying leaves and trunks with

fungicides.

Figure 26-Sycamore tree with Acremonium

wilt.

Sycamore Decline and Dieback, various

causal agents

Importance.-Sycamore decline,

sometimes called dieback, has been reported since the 1950’s across the Southem United States. The recurrence of this

problem has led some companies to curtail or halt commercial plantations.

Identifying the Disease.-Sycamore

decline typically appears as foliar necrosis and branch dieback in tree crowns

throughout a plantation (fig. 27a). Individual crown symptoms include sparse

foliage, dead branches, and scorched

leaves (fig. 27b, c). Similar symptoms can

be caused by canker fungi such as C.

fimbriata$ platani (p. 28), B. rhodina (p.

30), and P scabra (p. 33), or the bacterium X. fastidiosa (p. 24), which often is

associated with sycamore decline.

Identifying the Causal Agents.-

The combination of environmental and

biological agents contributing to sycamore decline may vary. Soil type, seed

source, weather (temperature and precipitation extremes), time of planting, and

plant culture can affect or trigger decline

events. Specific pathogens and insects that

attack declining trees are described elsewhere in this guide.

Biology.-Sycamore decline results

from a combination of environmental and

biological stresses and subsequent attacks

by opportunistic pests. An abiotic factor,

e.g., soil type or drought, will predispose

a tree or stand of trees; and another abiotic or biotic factor, e.g., freezing temperatures or insect defoliation, will trigger a decline that results in mortality from

various diseases and insects.

Control.-There is much to learn

about sycamore decline. Planting clones

with some disease resistance on sites that

are well suited for sycamore and avoiding unnecessary wounding may be the best

way to prevent sycamore decline. ’

26
Figure 27-(a) Sycamore decline, expressed as leaf scorching, thin crowns, and branch dieback, in a

S-year-old plantation in southern Alabama in August. Xylellu fastidiom and Botryosphaeria cankers

were present in this stand; (b) Trees inside the stand in (a) showing branch dieback and sparsely

foliated crowns; (c) dieback and epicormic branching in a 4-year-old plantation. Note the exposed,

inactive canker, likely Botryosphaeria, on the tree at center.

27
CANKERS

Canker Stain, Cerutocystisfimbriutu f. pkztuni (Ellis & Hal%) J.M. Walter

Importance.-Canker stain is a

deadly disease that occurs on sycamore

and London planetree from New York to

Georgia and west to Missouri. It poses a

threat to natural stands and plantations

throughout the South.

Identifying the Disease.-Canker

stain is hard to detect early in its development, especially under older, scaly bark

(fig. 28a). It may not be noticed until

symptoms appear in the crown. Long,

purplish-black, lens-shaped cankers form

on stems and large branches. Cankers

expand laterally about 9 cm per year and

lengthen up to 3 m per year. Growth follows the wood grain, often resulting in a

helical-shaped canker (fig. 28b). Phloem,

cambium, and sapwood mortality cause

parts of the crown to wilt suddenly and

then die (fig. 28e). In the South, older

cankers are often colonized by L.

theobromae (p. 30).

Identifying the Fungus.-Conidia

are produced on initial infection sites and

in well-colonized tissue. Black perithecia

with long (1 mm) necks produce hatshaped ascospores. Diseased sapwood has

brown-black, wedge-shaped staining that

is evident in stem cross sections (fig. 28d).

Biology.-Both spore types are sticky

and are spread by humans and insects. The

fungus can infect even the smallest wound

that exposes cambium or sapwood.

Control.-To prevent spreading canker stain to healthy trees, tools used to

prune diseased landscape trees should be

sprayed with a solution of rubbing alcohol and 50 percent laundry bleach. Wound

dressings are of little value. Early detection and removal of diseased trees in plantations can reduce losses. “Sanitation

cuts” of diseased stands should precede

planting sycamore trees in adjacent areas.

Figure 28-(a) Diagonal line from top center to lower right of bole defines right margin of a canker

stain canker; (b) the same canker shown in (a) after removing the bark

2 8
Figure 28 (continued)-(c) Canker stain canker several years old with decay and woodpecker

holes; (d) wedge-shaped, dark staining extends from the dead cambium into the sapwood; (e)

mature sycamore with crown dieback resulting from canker stain disease.

29
Botryosphaeria Canker, Botryosphaeria rhodina (Cooke) Arx

Importance.-This fungus attacks

many species of woody and herbaceous

plants worldwide. In the South, B. rhodina

causes cankers, dieback, and mortality in

natural stands and plantations.

Identifying the Disease.-Cankers,

ranging in length from a few centimeters

to several meters, form on twigs,

branches, and main stems. Young and

active cankers may be hard to see until

sections of bark die revealing canker margins and fruiting bodies breaking through

the bark (fig. 29a). Old, inactive cankers

appear sunken and are typically surrounded by a callus ridge (fig. 29b). Dieback occurs above plant parts girdled by

a canker.

Identifying the Fungus.-The

asexual form of the fungus, Lasiodiplodia

(=Botryodiplodia) theobromae (Pat.)

Griffon & Maubl.) occurs more commonly than Botryosphaeria rhodina.

Many black, pinpoint-sized pycnidia occur in groups, sometimes in rows, aligned

with the wood grain. As the fungus advances in the sapwood, it causes a dark

stain that can be seen beneath the bark

and in cross sections of the stem.

Biology.-Conidia typically enter

wounds made by cultivating, harvesting,

or insects. Canker formation and disease

development are enhanced by stress from

drought, poor site conditions, or other

diseases such as a wilt or canker stain (p.

28). Cankers grow faster, and seedlings

are killed more quickly at warmer temperatures (30-35 “C).

Control.-Promoting tree vigor by

planting sycamores on good sites and

avoiding dry, sandy sites should reduce

the incidence of Botryosphaeria cankers.

Pruning ornamental sycamores and

thinning or harvesting plantations (where

regeneration is by coppice growth) should

be done in the fall and winter

(temperatures I 20 “C) when the fungus

is less active.

Figure 29-(a) Active Botryosphaeria canker on a sycamore stem; (b) inactive Botryosphaeria canker

surrounded by callus on a sycamore stem.
Anthracnose-Twig Canker and Shoot Blight, Apiognomonia (=Gnomonia)

veneta (Sacc. & Speg.) Hahn.

Importance.-Anthracnose is one of

the most important diseases of sycamores

and Platanus species worldwide. It occurs in sycamore trees throughout North

America. Severe defoliation in consecutive years can weaken trees, making them

susceptible to attacks from other agents

and even causing death.

Identifying the Disease.-This fungus causes cankers on branches, blighting of twigs and shoots, and blighting of

leaves (p. 22), which can, in some years,

cause near total defoliation. Newly

emerged leaves and young shoots are

killed in early spring, often following cold

weather, which causes the symptoms to

be mistaken for frost damage (fig. 30a).

Repeated shoot dieback can cause an angular branch pattern in older trees as

shoots from lateral buds replace dead terminals. Cankers (3 to 8 cm long) form on

small branches (fig. 30b), and those that

do not girdle a branch in a year have callous ridges at the margins.

Identifying the Fungus.-Colorless,

ascospores, which have two unequal cells,

are released in spring from black perithecia on fallen leaves. Conidia are produced in small cups on dead leaves in

spring and in small (0.5 to 0.9 mm) black

pycnidia in the bark of twigs.

Biology.-Cankers form in the dormant season when temperatures are warm

enough for fungal growth. Within 2 weeks

after bud break, temperatures above 15

“C favor healthy shoot development,

whereas temperatures below 12 “C slow

shoot growth and favor the killing of

shoots and twigs. The antbracnose fungus probably enters sycamore trees

through their leaves; canker formation and

shoot blight occur in subsequent years.

Control.-(See p. 22).

Figure 3&(a) Shoot blight, caused by sycamore anthracnose, can be mistaken for frost damage;

(b) branch canker, with a callus ridge, from a sycamore anthracnose infection.
Hypoxylon Canker, Hypoxylon tinctor (Berk.) Cooke

Importance.-Hypoxylon tinctor is a

fairly common saprophyte of dead sycamores and other hardwood species. The

fungus occasionally produces cankers on

live sycamores, taking advantage of trees

in “decline” or under stress. In Georgia,

it has been associated with cankers caused

by the canker stain fungus Ceratocystis

fimbriata $ platani (p. 28).

Identifying the Disease.-Irregularly

defined, somewhat inconspicuous cankers

tend to follow the wood grain, occurring

mostly on the main stem and larger

branches (fig. 31a). Older, decayed cankers nq have holes from insect borers

or woodpeckers (fig. 31b).

Identifying the Fungus.-The darkbrown to black fungal stromata (1 to 5

cm x 2 to 30 cm) may be evident through

sloughing bark or may be partially concealed by bark (fig. 31~). Ascospores are

produced in tiny cavities embedded in the

hard surface of the stromata.

Biology.-The occurrence of H.

tinctor seems to be associated with extensive thinning in natural stands, where

other fungal pathogens and sun scald may

be weakening trees. Infection by windblown or rain-splashed ascospores probably occurs through wounds in the bark.

Control.-H. tinctor apparently is

less able to infect healthy, vigorously

growing trees. Therefore, maintaining

good tree vigor and minimizing bark

wounds should prevent cankers caused by

this fungus.

Figure 3 l-(a) Hypoxylon canker with bark removed to reveal fungal stromata; (b) dead, decaying

limb showing dark fungal stromata and a woodpecker using the limb as a nesting site; (c) closeup of

H. tincfor fungal stromata.

32
Miscellaneous Cankers, Phomopsis scubru, (Sacc.) Traverso; Dothiorellu sp.

Importance.-These fungi cause cankers that are generally less of a problem

than the canker fungi mentioned earlier

in this guide. Phomopsis scabra and

Dothiorella sp. can cause serious dieback

and mortality when environmental conditions weaken the host.

Identifying the Disease.-Phomopsis scabru can cause cankers ranging from

10 cm to 1 m in length and may be mistaken for cankers caused by

Botryosphaeriu rho&a (p. 30). Cankers

of both fungi are usually associated with

dead buds, terminals, or lateral branches

(fig. 32). At first, cankers may go undetected until the disease has progressed

enough to cause small, off-color leaves,

branch dieback, or tree death. Cankers

will become dark and sunken after 1 to 2

growing seasons.

Identifying the Fungi.-Both fungi

form spores in small, light-colored, flaskshaped fruiting bodies (usually pycnidia)

formed on host tissue. Phomopsis scabra

conidia are colorless, spindle-shaped, or

slightly curved single cells. Dothiorellu

spores are colorless, one-celled, and oval.

Biology.-Phomopsis scabra cankers

seem to develop readily at temperatures

below 24 “C. Growth of Dothiorella cankers slows during the growing season allowing callus tissue to form. Spores of

both fungi are spread by wind, rain, insects, and mechanical means. They enter

through wounds.

Control.-Damage from these fungi

can be reduced by preventing wounds and

promoting tree vigor by planting on good

sites.

Figure 32-Phomopsis cankers on branches of a site-stressed sycamore.
ROOT AND BUTT ROTS

Armillaria Root Rot, Armilluria tabescens (Stop.) Dennis, Orton & Hora

Importance.-Armillaria root rot is

one of the most common and damaging

diseases of many hardwood forest and

shade trees in North America. However,

it occurs less often on sycamores than on

other hardwood species.

Identifying the Disease.-Trees exhibit a loss of vigor and gradual decline,

yellowing of foliage, growth reductions,

premature leaf drop, and branch dieback.

In severe cases, and, given enough time,

A. tubescens can kill a tree.

Identifying the Fungus.-Following

rains, clusters of A. tabescens may form

at the base of diseased trees or from their

roots. The mushroom is honey colored to

brown, with white gills and a round cap

that is 4 to 15 cm in diameter (fig. 33a).

White, perforated fungal mats that form

beneath the bark at the root collar, or on

roots, are diagnostic (fig. 33b).

Biology.-The fungus survives as

mycelium in the roots and stumps of dead

trees from which it spreads to adjacent

trees. Trees weakened by mechanical

wounding or stressed by other pests are

more susceptible to attack.

Control.-Prevention is difficult because the fungus is prevalent in woody

debris in the soil and has a wide host

range. Wounding of tree trunks or severing roots with cutting tools or heavy

equipment should be avoided. Minimize

stress to landscape and shade trees by promoting tree vigor through watering during periods of drought and fertilizing during the growing season. Roots and stumps

of trees killed by A. tabescens should be

removed to reduce sources of inoculum

that could infect surrounding trees. Control other insect and disease pests that can

reduce vigor and weaken resistance to

infections.

Figure 33-(a) Mushrooms and (b) mycelial mats (

-___. -. .-.

of Armillaria tabescens.
Hericium Butt Rot, Hericium erinaceus (Pers.:Fr.) Murr.

Importance.-Hericium butt rot most

commonly occurs in oaks, but it is also

found in many other hardwoods throughout the Eastern United States, including

sycamore, beech, birch, hickories, maples,

and persimmon trees.

Identifying the Disease.-The fungus causes a white, soft, and spongy rot

of heartwood in the butt and lower bole

of the tree. Decayed wood eventually disintegrates leaving a cavity in the center

of the tree. Because external cankers are

not formed in the outer bark, no evidence

of the disease is visible except for seasonal fruiting bodies.

Identifying the Fungus.-Large (up

to 30 cm wide), soft, white, and fleshy

fruiting bodies form on the boles of living trees, singly or in clusters, during the

rainy autumn and winter months. They are

initially round and smooth on all surfaces,

but develop long, pendant “teeth” on the

lower surface and gradually turn yellowish with age (fig. 34).

Biology-Spores of the fungus, released from fruiting bodies on infected

trees, germinate and infect trees through

fire or logging scars, stem cracks, and

branch stubs near tree bases. Fruiting bodies form after extensive decay of the heartwood has occurred.

Control.-Hericium butt rot is best

controlled when thinning stands by preventing wounds and broken branches on

residual trees caused by logging equipment, skidding logs, and falling trees. Preventing fire scars is also suggested.

Figure 3iCFruiting bodies of Hericium ehaceus on a fire-scarred sycamore.
Oxyporus Root Rot, Oxyporus latemarginatus (Durieu & Mont.) Donk

Importance.-Oxyporus root rot

causes decay of roots and root collars in

sycamore, cottonwood, and many other

hardwoods in the South.

Identifying the Disease.-Few diagnostic symptoms are known for this disease. Young trees exhibit reduced annual

growth, stunting, and high mortality,

whereas older trees often survive several

years. The fungus causes a spongy white

rot of the sapwood and enlarged cankers

on the outer bark.

Identifying the Fungus.-The fungus invades the sapwood of roots as well

as the wood behind fire scars in the lower

bole, forming white mycelial mats and

dirty white to pale yellow fruiting bodies

at the soil line of dying or recently killed

trees. The fruiting bodies are active for

one season (fig. 35). Soil around diseased

roots and the root collar may become infested, forming a white crust of mycelial

strands on the soil surface at the stem base.

Biology.-Oxyporus latemarginatus

colonizes and survives on dead wood or

roots in the soil from which it invades

small feeder roots of healthy trees. It then

spreads to the root collar, colonizing the

outer and inner bark, cambium, and sapwood.

Control.-Trees are predisposed to

attack during warm weather, especially

when the soil is waterlogged, or when

feeder roots are wounded mechanically

or by fire. The disease can be managed

by preventing fiie and mechanical wounding to roots and the lower trunk and by

maintaining adequate soil drainage. Tree

vigor should be maintained by watering,

fertilizing, and controlling weeds. If possible, soil with infested dead wood should

be removed.

Figure 35-Fruiting body of Oxyporus latemarginatus on a young sycamore stem.

36
Ganoderma Butt Rot, Gunoderma Zucidum (Curtis:Fr.) P. Karst.

Importance.-This fungus is one of

the most commonly observed causes of

butt rot in southern hardwoods. A true

pathogen, it is often responsible for premature death of residential and landscape

trees. It can kill large trees and frequently

causes decay in declining trees.

Identifying the Disease.-Ganoderma lucidum causes a white, spongy

soft rot of sapwood and heartwood in the

roots and lower bole. Diseased trees eventually lose vigor, bear undersized leaves

and dead branches, and sometimes have

wilted or yellow leaves. However, fmiting bodies may form at or near the ground

on apparently healthy trees.

Identifying the Fungus.-The upper

surface of G. lucidurn’s large, reddishbrown fruiting bodies usually has a shiny,

varnished look and a leathery texture (fig.

36a). The fruiting bodies may form singly or in overlapping clusters at ground

level or on the lower bole of sycamores.

The margins are white, becoming a tawny

yellow with age. The lower surface of a

fruiting body has pores. Brown spores

released from fruiting bodies often form

a dustlike coating on grass, bark, or the

fruiting bodies themselves.

Biology.-Ganoderma lucidum infects trees through wounds on roots or the

lower bole caused by tools, lawn mowers, and falling trees or limbs. The decay’s

lethal effects occur when living cells in

the sapwood are killed. A decay column

may form for many years before sufficient

damage causes visible symptoms in the

crown. Fruiting bodies eventually form

and may occur repeatedly during the summer months. Living trees with decay in

the roots or lower bole are subject to

windthrow (fig. 36b).

Control.-This disease is best controlled by preventing mechanical wounds

to the lower bole and roots. Care should

be taken not to injure landscape trees,

especially when using heavy equipment

to clear land when preparing sites for

home building.

Figure 3&(a) Note the glossy, red-brown top and stalk of this G. lucidum fruiting body;

(b) advanced decay in this canker, along with insect and bird damage, poses a hazard.

37
Scytinostroma Root Rot, Scytinostroma (=Corticium) galactinum (Fr.) Donk

Importance.-Seedlings of sycamore

and other southern hardwoods such as

sweetgum, white oak, and nuttall oak are

very susceptible to Scytinostroma root rot.

The pathogen may kill young seedlings

within a month to a year after infection.

Fortunately, the disease is not common in

southern sycamores.

Identifying the Disease.-The fungus causes a white rot of roots in the collar and lateral roots of the taproot. Lateral roots may decay and, in severe cases,

separate from the taproot. Infected seedlings may be dwarfed, have thin crowns,

yellowing or dead leaves, and exhibit reduced vigor or decline prior to death.

Dead leaves usually remain on the plant

after death.

Identifying the Fungus.--Scytinostroma galactinum produces thick, white

fungal mats on the surfaces of the root

collar and roots below the collar (fig. 37).

Fungal mats are visible below the soil line

when soil is removed from the base of a

tree. Fruiting bodies of this fungus are I

very small and inconspicuous, forming

from fungal mats on the roots and root

collar.

Biology.-Scytinostroma galactinum

infects trees through wounds at the root

collars of seedlings. Lateral and feeder

roots often are killed. The fungus can then

survive on dead roots and stumps and

spread to living roots. Spores from fruiting bodies also may produce hyphae that

infect seedlings.

Control.-Sycamore seedlings and

saplings are most susceptible to this disease. Care should be taken to prevent the

mechanical wounding of the root collar

and lateral roots of seedlings. Removal

of diseased seedlings will help minimize

the fungus’ spread to healthy seedlings,

but no controls are feasible in natural

stands.

Figure 37White mycelial mats on roots and root collars of young sycamore (top) and cottonwood

(bottom) trees.

3 8
PARASITIC PLANTS

Mistletoe, spp.

Importance.-Extensive infections

and mortality are not common in sycamore trees. Infections usually occur in

openly grown trees. Phoradendron plants

are commonly used as greenery in Christmas decorations.

Identifying the Injury.-An affected

branch may have a gall or swelling at the

site of infection, and multiple infections

may retard growth. Stunting and dieback

may occur beyond where the mistletoe

plant is attached to its host.

Identifying the Parasite.-Mistletoe

has stout, woody, green stems and darkgreen, leathery leaves (fig. 38a). It is seen

most easily in winter growing on scaffold

and minor branches and twigs of the host

(fig. 38b). The plant has opposite branching, inconspicuous flowers, and produces

white berries in the fall and winter.

Biology.-Mistletoe is a perennial

evergreen plant that grows on tree

branches from which it draws water and

nutrients. Its seeds are covered with a

sticky, gelatinous coating and are spread

by birds and animals. Seeds germinate

where they lodge on young branches, and

a rootlike structure penetrates the branch

and produces a mistletoe plant. One species, l? serotinum, affects many broadleaf

tree species in the South and East but is

limited by temperature in its northern

range (Kansas to New Jersey). Several

other species of Phoradendron occur in

the West.

Control.-Control of mistletoe in sycamores is normally not needed but can

be done by cutting the host branch at least

30 cm below the point of infection.

Figure 38-(a) Closeup of a mistletoe plant; (b) mistletoe infections in a mature sycamore.
AIR POLLUTION AND CHEMICAL INJURIES

Air-Pollution Injury

Sycamore trees are sensitive to ozone,

sulfur dioxide, and fluorides, which are

released from point-source industrial

plants. Consequently, injuries from airborne pollutants often occur near these

plants. Airborne pollutants may also cause

damage to trees for some distance downwind of the source. Pollutants damage

plant foliage by oxidative processes that

interrupt normal physiology. Symptoms

include stippling, interveinal and marginal

chlorosis, and general bleaching of leaves

(fig. 39a). Reducing point-source emissions is the only known control. Drought

stress (fig. 39b) and some pathogens (e.g.,

p. 24), can cause leaf symptoms that may

be mistaken for air-pollution injury.

Chemical Injury

Sycamore trees are sensitive to several

agricultural pesticides, including herbicides and fungicides that are commonly

used to control pests in field crops.

Clomazone and phenoxy compounds like

2,4-D, are examples of herbicides that can

cause chemical injuries when they drift

during aerial applications. At higher concentrations, these materials produce

symptoms of leaf distortion, curling, and

chlorosis (fig. 39c, d). Solvent carriers in

fungicide sprays can damage sycamores.

Damage from pesticide spray drift can be

avoided by carefully planning applications and spraying during periods of low

wind.

Figure 39-(a) Tan flecking caused by ozone injury; (b) interveinal necrosis from drought stress; (c)

bleaching of leaves caused by the herbicide clomazone; (d) cupping, curling, and necrosis of leaves

caused by the herbicide 2,4-D.

40
MAINTAINING TREE HEALTH

Because healthy trees are less susceptible

to attack and injury by insects and diseases, sycamore plantings should be

managed to optimize vigor. Seedlings

and saplings that become stressed when

planted “off site” or on marginal sites,

and become further weakened by drought

or other factors, are sometimes devastated by disease. The following cultural

practices, singly or in combination, are

suggested to promote and maintain good

tree health in forest stands, plantations,

nurseries, shelterbelts, and ornamental

plantings:

1. Plant sycamore in deep, well-drained,

loamy soils with a good supply of ground

water such as alluvial soils, terrace soils,

and fertile sites in coves and lower slopes.

Site selection is the single most important factor in maintaining tree health and

minimizing losses from diseases and insects.

2. Where possible, avoid planting sycamores on abandoned old-field sites

with well-developed, impermeable hardpans, especially those that have been

badly eroded and leached.

3. Use only vigorous planting stock (of

adequate size and free of root and stem

diseases) produced in nurseries that

strictly follow recommended practices

for growing, lifting, storing, and handling

seedlings and cuttings.

4. When it is available, use planting

stock from improved selections grown in

sycamore seed orchards or from a locally

adapted seed source. (Some research has

shown that plants from seed sources north

of a planting site are more severely dam-

, aged by certain canker diseases than

those from seed sources south of the

planting site.)

5. Ensure that trees receive sufficient

water, nutrients, and sunlight through irrigation, fertilization, proper spacing, and

other intermediate stand-management

practices, such as timely thinning and

crop-tree release cutting.

6. Use sanitation practices such as pruning, removing dead and symptomatic

branches, and raking, discing under, or

removing diseased and insect-infested

leaves. Such practices reduce buildup of

overwintering fungal inoculum and hibernating insects in plant debris that can

cause new pest problems the following

year.

7. Prevent or minimize injuries by harvesting and cultivation equipment, fire, or

other sources that can create entry points

for canker fungi, wood-decay fungi, and

insect borers.

8. If pruning must be done, schedule it

for the dormant season when fungi are inactive and less likely to colonize fresh

wound sites. Always sterilize pruning

tools with a solution of 50 percent laundry bleach and water before moving to

the next tree.

9. Losses from canker diseases may be

reduced substantially by early detection

and shortened cutting cycles. However,

when a shorter cutting cycle is not possible, cankered trees should be felled and

destroyed or removed to minimize disease

spread. Sanitation cuts of unmerchantable

stands containing canker diseases are recommended when adjacent sites are to be

planted in sycamore.

10. Managers should learn to identify

serious diseases such as canker stain.

Identification errors can result in premature and unneeded salvage harvest or failure to harvest trees that will die or be-
come unmerchantable before the next

cutting cycle.

11. Strictly follow label guidelines when

using herbicides around ornamental

plantings and shade trees as well as in

nurseries and young plantations. Adequately shield young trees from direct

contact or spray drift. When used improperly, herbicides can injure young sycamore trees.

12. Examine plantings regularly for disease symptoms and the first signs of insect feeding. Early detection will allow

for the greatest number of pest-management options.

13. Insect pheromones and traps are

available commercially for monitoring a

number of species. Determining local,

seasonal abundance can help establish the

need for control and proper timing of insecticide application.

14. For information on pesticides or additional assistance with sycamore pests,

contact your State Forester, county extension agent, or the nearest office of the

USDA Forest Service, State and Private

Forestry, Forest Health Protection.

42
We appreciate the constructive reviews of this manuscript for scientific

content from: Edward Barnard, Division

of Forestry, Forest Health Section,

Gainesville, FL; Richard Goyer, Louisiana State University, Baton Rouge, LA;

Lynne Thompson, University of Arkansas at Monticello, AR; and R. Jay Stipes,

Virginia Polytechnic Institute and State

University, Blacksburg, VA.

We gratefully acknowledge the following individuals or agencies for photographs or specimens for making photographs of some pests: J.F. Butler, University of Florida, Gainesville, FL (white

marked tussock female moth); L.C. Thompson, University of Arkansas at

Monticello, Monticello, AR (fall webworm egg mass, drab prominent larva,

case-bearing leaf beetle larva); W.T.

Johnson, Cornell University, Ithaca, NY

(sycamore plant bug and leaf injury,

American plum borer injury); R.J. Gill,

California Department of Food and Agriculture, Sacramento, CA (European fruit

lecanium); EM. Davis, USDA ARS, Mississippi State University, MS (European

corn borer larva); J.C. Nord (retired),

USDA Forest Service, Athens, GA

(Colombian timber beetle); G.J. Lenhard,

Louisiana State University, Baton Rouge,

LA (whitefringed beetle adult); G.W.

Zehnder, Auburn University, Auburn, AL

(whitefringed beetle larvae); R. J. Stipes,

Virginia Polytechnic Institute and State

University, Blacksburg, VA (untreated

sycamores with anthracnose vs. fungicidetreated sycamore); J.L. Sherald, Center

for Urban Ecology, National Park Service,

Washington, D.C. (branch symptoms

caused by Xylellufustidiosa); J.N. Bruhn,

University of Missouri, Columbia, MO

(fruiting bodies and mycelial fan of

Armillaria tabescens); L.W. Kress,

USDA Forest Service, Research Triangle

Park, NC (ozone injury).

We also wish to thank the current and

former staff at the Southern Hardwoods

Laboratory, Stoneville, MS, and the

Southern Hardwood Forestry Research

Group, Stoneville, MS, for help in locating insect infestations and disease problems in the field to study and photograph

and for technical advice during this

project. Former staff of the Southern

Hardwoods Laboratory also provided

photographs that were used in this project.
GLOSSARY

acervulus(-i): a saucer-shaped fungal

structure embedded in host tissue in which

conidia form.

ascocarps: the sexual fruiting bodies of

Ascomycetes.

Ascomycetes: a large group of fungi characterized by producing spores in a saclike structure (ascus).

ascospores: sexual spores of Ascomycetes.

basidiocarps: the sexual fruiting bodies

of Basidiomycetes.

Basidiomycetes: a large group of fungi

characterized by producing spores on a

club-like structure (basidium).

basidiospores: sexual spores of Basidiomycetes.

bole: the main trunk of a tree.

butt: the lower bole of the main stem.

callus: a protective tissue that forms to

cover wounds on stems and branches.

cambium: a thin layer of meristematic

cells between the bark and wood.

cankers: a definite localized necrotic lesion of the bark and cambium.

cleistothecimu(-ia): roundish ascocarps

of powdery mildews, typically with appendages, in which ascospores form.

conidium(-ia): an asexual fungal spore.

damping-off: a disease of seedlings that

causes rotting of the hypocotyl and prevents shoot emergence, or causes a new

shoot to fall over.

dieback: the gradual dying of a tree crown

usually from the top down and from the

outside in.

ELISA test: enzyme-linked immunesorbent assay; a test that detects a specific molecule, usually a protein, consistently associated with a certain organism.

elytron (a): hard leathery forewing of

beetles.

frass: wood fragments mixed with excrement produced by insect larvae.

hair pencil: tuft of long upright parallel

setae (hairs).

hypha(-e): a fungal filament.

inoculum(-a): the spores, mycelium, or

other propagules of a pathogen that initially infect a host.

microsclerotium(-ia): a firm, often

rounded, compact mass of fungal hyphae

that are packed together to form a resistant structure.

mycelium(-ia): a collection of hyphae that

make up a fungus body.

necrotic: composed of dead cells.

perithecium(-ia): flask-shaped ascocarps

in which ascospores are formed.

saprophytic: the ability to grow on dead

plant tissue.

sapwood: the outer, water-conducting

wood of the tree stem.

sporodochium(-ia): a cushion-shaped

stroma covered with conidiophores.

stroma(-mata): a mass or mat of hyphae

in or on which fruiting bodies form.

44


Leininger, T.D.; Solomon, J.D.; Wilson, A.D.; S&if& N.M. 1999. A Guide to

major insects, diseases, air pollution injury, and chemical it-jury of sycamore.

Gen. Tech. Rep. SRS 28. Asheville, NC: U.S. Department of Agriculture,

Forest Service, Southern Research Station. 44 p.

This booklet will help nurserymen, forest woodland managers, pest control

operators, and homeowners to identify and control pest problems on sycamore

trees. The major insect and disease pests of sycamores in the Eastern United

States are emphasized. Descriptions and illustrations of the pests and the

damage they cause are provided to aid in identification. Brief notes are given on

biology and control to aid in predicting damage and making control decisions.

Keywords: Bacteria, biology, borers, control, defoliators, fungi, identification,