Forest Service

Northeastern Area

State & Private Forestry

Revised August 2017

How To

NA–FR–01–15

Recognize Common 

Diseases of Oaks in 

the Midwest: 

A Quick Guide
Author

Jill D. Pokorny, U.S. Forest Service

Northeastern Area State and Private Forestry

Editor

Sandra Clark, U.S. Forest Service

Design and Layout

Juliette Watts, U.S. Forest Service

Cover Photos

Top left: Anthracnose leaf symptoms

Top right: Oak wilt leaf symptoms

Middle left: Bur oak blight leaf symptoms

Middle right: Bacterial leaf scorch leaf symptoms

Bottom left: Oak leaf blister leaf symptoms

Bottom right: Botryosphaeria twig canker symptoms

Acknowledgements

The author thanks Joseph O’Brien, Sandra Gould, and 

Steve Katovich for their reviews of the manuscript.

Photo and Illustration Credits

Robert Anderson, U.S. Forest Service, Bugwood.org

(figures 8, 26)

D.W. French, University of Minnesota, St. Paul, MN

(cover top right)

Ann Gould, Rutgers University (cover middle right; figures 

17, 18) 

Robert A. Haack, U.S. Forest Service, Bugwood.org

(figures 23, 24) 

Tom Harrington, Iowa State University (figure 3)

John Hartman, University of Kentucky, Bugwood.org

(figure 19)

Steven Katovich, U.S. Forest Service, St. Paul, MN (figure 20)

Julie Martinez, Scientific Illustrator, Minneapolis, MN

(figure 1)

Joseph O’Brien, U.S. Forest Service, St. Paul, MN

(figures 10, 27)

Jill Pokorny, U.S. Forest Service, St. Paul, MN (cover top left, 

middle left, and bottom right; figures 2, 4–7, 11–16, 21,

and 25)

James Solomon, U.S. Forest Service, Bugwood.org

(figure 22)

David Stephens, University of Georgia, Bugwood.org

(cover bottom left, figure 9)

Curtis E. Young, The Ohio State University, Bugwood.org

(figure 28)
How To

Recognize Common 

Diseases of Oaks in 

the Midwest: 

A Quick Guide

Forest Service

Northeastern Area

State and Private Forestry

11 Campus Boulevard

Suite 200

Newtown Square, PA 19073

NA–FR–01–15

Revised August 2017

www.na.fs.fed.us

Table of Contents

Purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Bur Oak Blight (BOB). . . . . . . . . . . . . . . . . . . . . 4

Anthracnose. . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Oak Leaf Blister. . . . . . . . . . . . . . . . . . . . . . . . . 8

Botryosphaeria Twig Canker. . . . . . . . . . . . . . 10

Oak Wilt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Bacterial Leaf Scorch (BLS). . . . . . . . . . . . . . . 14

Oak Decline (Part 1). . . . . . . . . . . . . . . . . . . . 16

Oak Decline (Part 2). . . . . . . . . . . . . . . . . . . . 18

Table 1. Management Options. . . . . . . . . . . . 21

Management Recommendations for

Bur Oak Blight (BOB). . . . . . . . . . . . . . . . . . . . 22

Northeastern Area State and

Private Forestry Offices. . . . . . . . . . . . . . . . . . 24

1

Purpose

This diagnostic guide was developed to help 

forestry professionals, forest woodland managers, 

and homeowners identify and manage the most 

common diseases of oak trees in Midwestern 

States. It discusses the most common diseases of 

oak, some of which can be easily confused with 

others. It compares and contrasts key features of 

each disease to help you distinguish one disease 

from another.

This guide provides descriptions and images of 

the diseases and the damage they cause. It also 

presents information on diagnostic features 

for each disease—host range, causal agent(s), 

symptom expression, timing and distribution 

within the tree, impact on tree health, pattern of 

tree damage on site, and general management 

options—in an easy-to-read table format.

This guide focuses on key diagnostic information 

to keep it brief and pocket sized for use in the 

field. It does, however, provide a link for more 

detailed information for each disease. In the case 

of bur oak blight, more detailed management 

recommendations are provided since this 

information is not published elsewhere.
2

Introduction

Oaks that grow in the Midwest can be organized 

taxonomically into two main groups based on 

leaf shape and other characteristics: red oaks 

and white oaks. Trees in both the red oak group 

and white oak group have fan-shaped leaves; 

however, red oaks have sharply pointed leaf tips 

while white oaks have rounded or blunt leaf tips 

(figure 1).
3

Red Oaks

White Oaks

Figure 1. Oak groups based on leaf shape. 

A. Northern red oak.

B. Northern pin oak. 

C. White oak.

D. Bur oak.
4

Bur Oak Blight (BOB)

Host Range Affects only Quercus macrocarpa var. 

oliviformis, the small-acorn variety of bur 

oak.

Causal Agent Fungus: Tubakia iowensis

Symptoms Leaf symptoms: Small, black spots 

develop on leaf veins; expand outward 

from the veins; and produce large, brown, 

wedge-shaped dead areas (lesions) on 

the leaf. Entire leaves may turn brown 

and appear scorched. Figure 2 shows the 

full range of leaf symptoms. Some leaf 

petioles become infected, turn brown, 

and die; black pustules form on the base 

of infected petioles (figure 3).

Leaf drop: Yes. Some premature leaf 

drop is typical in late summer. Some 

leaves with infected petioles remain on 

the tree thoughout the winter.

Sapwood discoloration: No.

Symptom 

Distribution 

within Tree

Bottom up, inside out.

Lower, inner portions of branches show 

leaf symptoms first (figure 4). Later 

symptoms spread upward and outward 

within the crown.

Timing of 

Symptoms 

Within Tree

Mid to late summer. Large, wedgedshaped lesions are evident. Symptoms 

may continue to spread during late 

summer and fall if rainy weather persists.

Impact on 

Tree Health

Symptoms develop late in the season. 

Disease progression within the tree is 

slow. Not a serious threat to overall tree 

health, unless repeated defoliations lead 

to tree stress and trigger decline and/

or invasion by secondary invaders such 

as the twolined chestnut borer and 

Armillaria root disease.

Pattern of 

Tree Damage 

on Site

Random and scattered. Some trees may 

be severely affected while neighboring 

trees appear healthy. This is likely due to 

variation in the resistance of individual 

bur oak trees to this disease.

Management

Options

See options 2, 5, and 9 in table 1 on

page 21 and page 22.

More 

Information 

See page 22.

http://na.fs.fed.us/pubs/palerts/bur_oak_

blight/bob_print.pdf (Accessed August 

2017)
5

Figure 2. Full range of leaf symptoms: dark veins; large, 

wedge-shaped lesions; and totally brown leaves.

Figure 3. Black, pimple-like pustules (see arrows) form on 

infected leaf petioles in late summer and fall.

Figure 4. Leaf symptoms first appear on lower branches and 

then progress upward in the tree’s crown.
6

Anthracnose

Host Range Affects both red and white oaks, but is 

more common on white oak.

Causal Agent Fungus: Apiognomonia quercina

(asexual stage: Discula spp.)

Symptoms Leaf symptoms: Individual and 

localized brown leaf spots develop 

anywhere on the leaves and are not 

restricted to leaf margins (figure 5). 

Leaf spots expand and often coalesce 

into large, brown blotches that have 

a papery texture (figure 6). Leaves 

may also become curled or distorted. 

Figure 7 shows the full range of leaf 

symptoms.

Compare to: Oak wilt and bacterial 

leaf scorch, which have browning of 

leaf tissue on the leaf tips and margins 

only and do not produce individual 

and localized leaf spots in the center of 

leaves.

Leaf drop: Yes. Common in the lower 

portions of the crown where the 

disease is most severe.

Sapwood discoloration: No

Symptom 

Distribution 

within Tree

Bottom up, inside out.

Lower, inner portions of branches show

leaf spot/blotch symptoms first. Later 

symptoms spread upward and outward 

within the crown.

Timing of 

Symptoms 

Within Tree

Spring and early summer, following 

periods of high rainfall in the spring. 

Symptoms may continue to spread 

during summer and fall if rainy weather 

persists.

Impact on Tree 

Health

Not a serious threat to overall tree 

health, unless repeated defoliations 

lead to tree stress and trigger tree 

decline and/or invasion by secondary 

invaders such as twolined chestnut 

borer and Armillaria root disease.

Pattern of Tree 

Damage on Site

Often widespread, particularly after 

periods of high rainfall in the spring.

Management

Options

See options 2, 3, 5, and 9 in table 1 on 

page 21.

More 

Information

http://extension.psu.edu/pests/plantdiseases/all-fact-sheets/anthracnoseon-shade-trees (Accessed August 2017)
7

Figure 5. 

Brown leaf 

spots develop 

anywhere 

on a leaf 

and are not 

restricted to 

the leaf tips 

or margins.

Figure 6. Leaf spots may expand into large, brown blotches 

that often have a papery texture.

Figure 7. Full range of leaf symptoms: small leaf spots in 

the center of the leaf and large, brown blotches that may 

encompass large portions of the leaf surface.
8

Oak Leaf Blister

Host Range Affects both red and white oaks, but is 

more common and severe on red oaks.

Causal Agent Fungus: Taphrina caerulescens

Symptoms Leaf symptoms: Blister-like areas 

develop on the upper leaf surface. 

The blisters are round, raised, and 

wrinkled (figure 8). They vary in color, 

first appearing yellowish (figure 9), 

then turning white, and later becoming 

brown to blackish (figure 10).

Leaf drop: Some defoliation may occur 

if leaf infections are severe. 

Sapwood discoloration: No.

Symptom 

Distribution 

within Tree

Bottom up, inside out.

Lower, inner portions of branches show 

leaf spot/blister symptoms first. Later 

symptoms spread upward and outward 

within the crown.

Timing of 

Symptoms 

Within Tree

Spring and early summer, following 

periods of high rainfall in the spring. 

May spread during summer and fall if 

rainy weather persists.

Impact on Tree 

Health

Heavy infections may be unsightly, but 

they do not endanger the health of a 

tree. 

Pattern of Tree 

Damage on 

Site

Often widespread, particularly after 

periods of high rainfall in spring and in 

sites that have poor air circulation.

Management

Options

See options 2,3, and 8 in table 1 on 

page 21.

More 

Information

http://plantclinic.cornell.edu/factsheets/

oakleafblister.pdf (Accessed August 

2017)
9

Figure 8. On the upper leaf surface, blisters are round and 

raised.

Figure 9. Blisters first appear yellowish.

Figure 10. Blisters later turn brown to blackish (see arrows).
10

Botryosphaeria Twig Canker

Host Range Affects both red and white oaks.

Causal Agent Fungus: Botryosphaeria spp. (asexual 

stage: Diplodia spp.)

Symptoms Leaf symptoms: Brown, wilted leaves 

on the tips of branches (figure 11). 

Dieback typically extends only 4 to 6

inches inward from the branch tips. 

Dark brown (almost black), elongated 

lesions (cankers) develop on affected 

branches (figure 12). Cankers injure the 

phloem and cambium tissue, impair 

the flow of water and nutrients, and 

induce the leaves beyond the cankers 

to turn brown and wilt.

Black, pimple-like fruiting structures

develop within the cankers

(figure 13).

Compare to: Twig pruner insects 

or cicada damage, which can cause 

similar branch tip dieback symptoms.

Leaf drop: Typically not; however,

minor leaf drop has been occasionally 

reported.

Sapwood discoloration: Yes. 

Associated with cankers.

Symptom 

Distribution 

within Tree

Random and scattered within the tree.

Only the outermost tips of branches 

are affected, not the whole branch, as 

is typical of oak wilt and bacterial leaf 

scorch. 

Timing of 

Symptoms 

Within Tree 

Mid-summer. Dead branch tips remain 

visible through the fall.

Impact on Tree 

Health

Minimal damage to the overall health 

of the tree. Cankers usually remain 

localized in small branches, resulting in 

dieback to branch tips only. 

Pattern of Tree 

Damage on Site

Often widespread, particularly after 

periods of high rainfall in spring.

Management 

Options

See options 2, 4, and 8 in table 1 on 

page 21.

More 

Information

http://pubs.ext.vt.edu/content/dam/

pubs_ext_vt_edu/450/450-726/450-

726_pdf.pdf (Accessed August 2017)
11

Figure 11. Red oak displaying brown, wilted leaves on the 

tips of branches.

Figure 12. Dark brown, elongated canker (see area between 

arrows) on an affected branch tip.

Figure 13. Black, pimple-like fruiting structures (see arrows) 

form on affected branches in late summer and fall.
12

Oak Wilt

Host Range Affects both red and white oaks, but is 

more common and severe on red oaks.

Causal Agent Fungus: Ceratocystis fagacearum (asexual 

stage: Chalara quercina)

Symptoms Leaf symptoms: Leaf browning starts 

at leaf tips and margins and progresses 

inward toward the midrib (figure 14).

The fungus invades the xylem vessels; 

impairs flow of water to the leaves; 

and induces symptoms of marginal 

watersoaking, leaf browning or bronzing 

(scorch), and wilting.

Compare to: Bacterial leaf scorch where 

a dull brown or yellow halo is evident 

between scorched tissue and healthy, 

green leaf tissue.

Leaf drop: Yes. Often very rapid and

extensive on red oaks. Many leaves on 

the ground may be green or only partially 

wilted. White and bur oaks experience 

less leaf drop.

Sapwood discoloration: Yes. Typically 

present and appears as gray-brown to 

black discoloration in the outer annual 

ring of sapwood (figure 15). Sapwood 

discoloration may sometimes be hard to 

see in red oaks.

Symptom 

Distribution 

within Tree

Top down, outside in. 

Upper, outermost tips of branches 

scorch and wilt first (figure 16). Soon 

after, symptoms can progress down the 

branches.

Timing of 

Symptoms 

Within Tree

Usually mid to late summer; can progress 

throughout the summer.

Impact on 

Tree Health

Red oaks: fatal and fast moving

(< 3 weeks).

White oaks: fatal, but slower moving

(1–5 years).

Pattern of 

Tree Damage 

on Site

Expanding pockets (root graft spread) 

or isolated trees (overland spread by sap 

feeding beetles).

New infections may be associated with 

tree wounding.

Management

Options

See options 6, 7, and 9 in table 1 on

page 21.

More 

Information

http://na.fs.fed.us/pubs/howtos/ht_oakwilt/

identify_prevent_and_control_oak_wilt_

print.pdf (Accessed August 2017)
13

Figure 14. Red oak leaves displaying the full range of 

oak wilt symptoms: marginal leaf scorch that progresses 

uniformly inward toward the midrib.

Figure 15. Infected red oak branch segment, with bark 

removed, to show dark discoloration in the sapwood. Left: 

Cross-sectional view showing discoloration in the outer ring 

of sapwood. Right: Longitudinal view showing dark streaks 

in sapwood.

Figure 16. Bur 

oak exhibiting 

brown, wilted 

leaves on 

scattered 

branches. The 

wilting started 

at the tips of 

branches and 

progressed 

down the 

branches.
14

Bacterial Leaf Scorch (BLS)

Host Range Affects both red and white oaks; most 

common on pin and red oak.

Causal Agent Bacterium: Xylella fastidiosa

Symptoms Leaf symptoms: Pronounced redbrown discoloration (scorch), starting at 

leaf tips and margins and progressing 

inward to midrib. On red oak, a yellow 

halo is present between the scorched 

tissue and healthy green tissue (figure 

17). On northern pin oak, the yellow 

halo may be absent and is replaced by 

a dull brown band that borders the 

scorched tissue (figure 18).

The bacterium invades the xylem vessels, 

impairs the flow of water to the leaves, 

and induces symptoms of marginal leaf 

scorch.

Compare to: Oak wilt, where the 

marginal leaf scorch pattern is more 

uniform vs. the often irregular and 

undulating pattern of BLS.

Leaf drop: Yes. Typically occurs one 

month earlier than normal leaf drop in 

the fall.

Sapwood discoloration: No.

Symptom 

Distribution 

within Tree

Starts with one or two scattered 

branches and spreads slowly to other 

branches within the crown each 

successive year of infection (figure 19). 

Most, if not all, leaves on an affected 

branch will show symptoms.

Timing of 

Symptoms 

Within Tree

Mid to late summer and into early fall.

Impact on 

Tree Health

Disease progression is slow. May take 

5–10 years before major branch dieback 

occurs. Eventually the disease may be 

fatal.

Pattern of 

Tree Damage 

on Site

Random and scattered. Some trees may 

be severely affected while neighboring 

trees appear healthy.

Management

Options

See options 1 and 2 in table 1 on page 

21.

More 

Information

http://www.usna.usda.gov/Research/

BacterialLeafScorch.html (Accessed 

August 2017)
15

Figure 17. Red 

oak displaying 

the pronounced 

yellow halo 

between the 

brown, scorched 

tissue and green, 

healthy tissue.

Figure 18. Northern pin oak displaying symptoms that 

are not as striking as those in red oak. The yellow halo is 

often not present, and only a dull brown band borders the 

scorched tissue.

Figure 19. 

Initially a single 

branch develops 

symptoms. 

Symptoms recur 

each year, with 

an increase in 

the number of 

branches affected.
16

Oak Decline (Part 1)

Host Range Affects all red and white oaks.

Causal 

Agent

Complex of long-term abiotic stress factors 

(climate, age, and site predisposition) 

combined with short-term stresses 

(defoliation, drought, flooding, and frost 

damage); often followed by invasion by 

opportunistic insects and fungi such as the 

twolined chestnut borer (Agrilus bilineatus), 

Armillaria root disease (Armillaria spp.), and 

red oak borer (Enaphalodes rufulus).

Symptoms: 

General 

Overview

Leaf symptoms: Red-brown uniform 

discoloration (scorch) of leaves; scorch 

symptoms can occur suddenly.

Small, upper-crown branches exhibit leaf 

symptoms first and begin to die back. 

Large branches and entire sections of the 

crown may die over time. Dieback proceeds 

from the top of the crown downward 

and creates a “stag-head” effect where 

large antler-like branches (with no leaves) 

stick up in the top of the tree’s crown. 

Red to brown, scorched leaves are often 

present in a transition zone between the 

leafless tips of branches and the base of 

branches where green, healthy leaves are 

present (figure 20). Under extreme stress 

conditions, the entire tree crown may 

exhibit brown, scorched leaves in one 

growing season.

Foliage may occur in clusters or tufts as a 

result of buds sprouting on branches and 

the trunk (figure 21). Some leaves may fail 

to develop in the spring or wilt shortly after 

bud break; others may appear chlorotic 

(yellow) or small. 

Leaf drop: No. Dead, scorched leaves 

are often retained a bit later than usual 

leaf drop in the fall, especially if twolined 

chestnut borer is present.

Sapwood discoloration: No.

Symptoms:

If twolined 

chestnut 

borer is 

present

Insect tunneling in symptomatic branches 

and/or the trunk, just beneath the bark 

(figure 22).
17

Figure 20. This tree shows the dead-brown-green pattern 

of crown symptoms: dead branch tips (stag-head); brown, 

discolored leaves in the transition zone; and green, healthy 

leaves at the base of affected branches and on lower branches.

Figure 22. When 

you remove the 

bark on affected 

branches or 

the main trunk, 

meandering 

tunnels (galleries) 

are evident on 

the surface of the 

sapwood.

Figure 21. Oak tree exhibiting tufted foliage growth on 

branches and the main trunk.
18

Oak Decline (Part 2)

Symptoms:

If twolined 

chestnut 

borer is 

present

(cont.)

Larvae, the immature stage of the insect, 

construct winding galleries of sufficient 

depth to impair the flow of water to the 

leaves, and induce symptoms of marginal 

leaf browning, scorch, and wilt (figure 23).

Emerging adults (figure 24) produce 

D-shaped exit holes (figure 25).

Dead, brown leaves usually remain 

attached to the tree a bit later than 

normal in the fall.

Symptoms: 

If Armillaria 

root disease 

is present

White mycelial fans (figure 26) and 

shoestring-like rhizomorphs (figure 27) 

grow between the bark and wood at 

the root collar and on roots. The fungus 

eventually girdles the root collar and large 

buttress roots and impairs the flow of 

water within the tree.

In the autumn, clusters of honey-colored 

mushrooms may form at the base of 

infected trees (figure 28).

Symptom 

Distribution 

within Tree

Top down, outside in. 

Upper, outermost tips of branches are 

affected first. Larger branches, whole 

sectors of the crown, or the entire tree 

may later die.

Timing of 

Symptoms 

Within Tree

Variable. Trees invaded by twolined 

chestnut borers generally exhibit the first 

visible symptoms of leaf scorch in mid to 

late summer.

Impact on 

Tree Health

Usually the progression of decline/dieback 

is slow, occurring over several years. 

However, progression of decline may be 

faster and result in tree death if large 

numbers of twolined chestnut borers 

attack the tree, Armillaria root disease 

is severe, or other stress factors are also 

present.

Pattern of 

Tree Damage 

on Site

Random and scattered. Often associated 

with site features such as ridge tops and 

wet areas where stress factors such as 

drought, defoliation, flooding, and frost 

damage occur.

Management

Options

See options 2 and 5 in table 1 on page 21.

More 

Information

http://www.na.fs.fed.us/spfo/pubs/fidls/

oakdecline/oakdecline.htm (Accessed 

August 2017)
19

Figure 23. Larvae of the twolined chestnut borer are white, 

slender, about 1 inch long when fully grown, and have two 

spines at the tip of the abdomen.

Figure 24. Adults are slender, black beetles that are 1⁄5 to 1⁄2 

inch long with two golden stripes along the back.

Figure 25. Emerging adult beetles produce characteristic 

D-shaped exit holes (arrow).
20

Figure 26. A white 

layer of fungal 

growth (mycelial 

fan) develops 

between the bark 

and the wood at 

the base of the tree. 

Some mycelial fans 

will glow in the 

dark.

Figure 27. Dark, 

shoestringlike structures 

(rhizomorphs) form 

on the base of the 

tree and grow just 

under the bark.

Figure 28. In the fall, the Armillaria fungus produces clusters 

of honey-colored mushrooms at the base of some infected 

trees.
21

Table 1. Management Options

1. There is no known cure, prevention strategy, 

or therapy.

2. Carry out cultural practices that promote the 

vigor of individual trees and stands (groups of 

trees being similarly managed):

For Homeowners

• Properly mulch trees, irrigate during dry 

periods, and fertilize if soil testing results 

indicate the need.

For Forest Land Managers

• Promote and develop trees with large, 

healthy crowns.

•Diversify age classes; do not allow oldage trees to dominant the stand.

•Avoid thinning in a stand when trees 

are under severe stress from drought 

or during an insect outbreak. Any 

disturbance will open up the stand to 

drying winds and cause additional stress 

to residual trees.

•Carry out silvicultural practices that 

encourage species best adapted to the 

site.

3. Rake fallen infected leaves and destroy.

4. Prune infected twigs and small branches and 

destroy. Prune in the winter when trees are 

dormant.

5. Prune deadwood and destroy. Prune in the 

winter when trees are dormant.

6. Avoid wounding or pruning oaks during the 

peak infection period—April, May, and June.

7. Prevent overland spread by removing infected 

trees in a timely fashion and properly treating 

wood. Prevent underground spread by 

severing root grafts with a vibratory plow or 

rupturing the roots.

8. Chemical controls are not typically warranted.

9. Treat high-value trees with a registered 

fungicide if tree health is endangered.
22

Management 

Recommendations for Bur Oak 

Blight (BOB)

The extent to which BOB damages the health 

of bur oak trees is not yet fully known. Because 

leaf damage and defoliation occur late in the 

season, BOB typically does not cause outright 

tree death; however, repeated and severe leaf 

damage and defoliation can stress trees and 

open them to attack by secondary invaders such 

as two-lined chestnut borer and Armillaria root 

disease. BOB, working in concert with these 

secondary invaders, can cause tree death. To 

date, many high-value landscape and park trees 

have experienced defoliation for 10 or more years 

and are severely stressed. These trees are prime 

candidates for the use of a fungicide treatment 

program aimed at reducing disease severity. The 

key to successfully managing BOB is to treat trees 

with a fungicide before they are severely stressed 

and before they become invaded by two-lined 

chestnut borers.

The fungicide propaconazole, injected at the rate 

of 10-15 ml per inch of d.b.h., has significantly 

reduced symptom development in trees for 3 or 

more years. To be effective, the fungicide should 

be applied in early spring as soon as the leaves 

are fully expanded. If applied later, the fungicide 

will not effectively reduce the primary infections 

and will not sufficiently lower the disease level. 

In forest stands, the current management 

alternatives are limited to removal of highly 

impacted trees.

Trees should not be re-treated until leaf 

symptoms again reach moderate disease 

levels. Since BOB is a slow-progressing disease, 

moderate leaf symptoms should not recur for 

several years. Raking up infected leaves will have 

little impact on reducing the occurrence of this 

disease because the fungus overwinters at the 

base of infected leaf petioles, most of which 

remain on the tree over the winter.
23

The good news is that not all bur oak trees are 

equally susceptible to BOB. In fact, within a 

stand, park, or yard landscape, some trees may 

be severely infected while adjacent trees appear 

healthy.
24

Northeastern Area State and 

Private Forestry Offices

Headquarters Office

Northeastern Area State and Private Forestry 

USDA Forest Service

11 Campus Boulevard, Suite 200 

Newtown Square, PA 19073

Durham Field Office

Northeastern Area State and Private Forestry 

USDA Forest Service 

271 Mast Road 

Durham, NH 03824-9799

Morgantown Field Office 

Northeastern Area State and Private Forestry 

USDA Forest Service 

180 Canfield Street 

Morgantown, WV 26505-3101

St. Paul Field Office 

Northeastern Area State and Private Forestry 

USDA Forest Service 

1992 Folwell Avenue 

St. Paul, MN 55108-1099
Pesticide Precautionary Statement

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 animals--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 honey bees 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 first-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 

material near ponds, streams, or wells. Because it 

is difficult to remove all traces of herbicides 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 at a sanitary land-fill dump, or 

crush and bury them in a level, isolated place.

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 be sure the intended use is still 

registered.

CAUTION: 

PESTICIDES 
EEO Statement

In accordance with Federal civil rights law and 

U.S. Department of Agriculture (USDA) civil rights 

regulations and policies, the USDA, its Agencies, offices, 

and employees, and institutions participating in or 

administering USDA programs are prohibited from 

discriminating based on race, color, national origin, 

religion, sex, gender identity (including gender expression), 

sexual orientation, disability, age, marital status, family/

parental status, income derived from a public assistance 

program, political beliefs, or reprisal or retaliation for prior 

civil rights activity, in any program or activity conducted 

or funded by USDA (not all bases apply to all programs). 

Remedies and complaint filing deadlines vary by program 

or incident.

Persons with disabilities who require alternative means 

of communication for program information (e.g., Braille, 

large print, audiotape, American Sign Language, etc.) 

should contact the responsible Agency or USDA’s TARGET 

Center at (202) 720-2600 (voice and TTY) or contact 

USDA through the Federal Relay Service at (800) 877-

8339. Additionally, program information may be made 

available in languages other than English.

To file a program discrimination complaint, complete 

the USDA Program Discrimination Complaint Form, 

AD-3027, found online at http://www.ascr.usda.gov/

complaint_filing_cust.html and at any USDA office or 

write a letter addressed to USDA and provide in the letter 

all of the information requested in the form. To request a 

copy of the complaint form, call (866) 632-9992. Submit 

your completed form or letter to USDA by: (1) mail: 

U.S. Department of Agriculture, Office of the Assistant 

Secretary for Civil Rights, 1400 Independence Avenue, 

SW, Washington, D.C. 20250-9410; (2) fax: (202) 690-

7442; or (3) email: program.intake@usda.gov.