United States

Department of

Agriculture

Forest Service

Northeastern Forest

Experiment Station

Research Paper NE-675

Recognizing and Managing

Sapstreak Disease of

Sugar Maple

David R. Houston
Abstract

Sapstreak disease is a potentially serious problem of sugarbushes and forest

stands. It occurs when the causal fungus, Ceratocystis virescens, invades the

sapwood of roots and bases of stems through wounds inflicted during logging,

saphauling, or other activities. This bulletin describes how to recognize the disease,

the factors that affect its occurrence and development, and management

approaches to help reduce its effects.

The Author

DAVID R. HOUSTON is a principal plant pathologist conducting research on

dieback and decline diseases at the Center for Biological Control of Northeastern

Forest Insects and Diseases, a laboratory of the U.S. Department of Agriculture,

Forest Service, Northeastern Forest Experiment Station, Hamden, Connecticut. For

the past 30 years Dr. Houston's research has focused on stress-initiated dieback

and decline diseases of deciduous hardwoods, especially beech, maple, and oak.

The use of trade, firm, or corporation names in this publication is for the information

and convenience of the reader. Such use does not constitute an official

endorsement or approval by the U.S. Department of Agriculture or the Forest

Service of any product or service to the exclusion of others that may be suitable.

Manuscript received for publication 15 March 1993

COVER PHOTO.--Small leaves often are the first obvious sympton of sapstreak

disease.

USDA FOREST SERVICE

5 RADNOR CORP CTR STE 200

PO BOX 6775

RADNOR PA 19087-8775

October 1993
Introduction

Sapstreak of sugar maple (Acer saccharum Marsh) is a

disease of the living sapwood incited by the fungus,

Ceratocystis virescens (Davidson) C. Moreau (=C.

coerulescens (Munch) Bakshi) (= Endoconidiophora virescens

Davidson) (Hepting 1944). Sapstreak, first noticed in North

Carolina in approximately 1935 (Hepting 1944), has since

been reported in Michigan in 1959 (Kessler and Anderson

1960), Vermont in 1964 (Houston and Fisher 1964), Wisconsin

in 1971 (Kessler 1972) and New York in 1978 (Beil and

Kessler 1979, Houston and Schneider 1982). In each case,

the disease occurred in stands where activities such as

logging, road building, or sap hauling had inflicted root or lower

stem wounds to the affected trees. These injuries allow C.

virescens to invade and then kill the wood of lower portions of

the stem and roots (Hepting 1944, Kessler 1978, Houston

1985). Because C. virescens is one of the most common fungi

in northern hardwood forests (Shigo 1962), sapstreak disease

has the potential to occur where the roots and lower stems of

Figure 1.--A thin "transparent " crown with leaves much

smaller than normal--the first indication that a tree may have

sapstreak disease.

sugar maple trees are wounded during logging or other

activities in these forests.

This paper presents information on (1) symptoms of the

disease, (2) factors affecting disease occurrence and

development and (3) management approaches to reduce

disease effects. This information was obtained from published

articles and a series of studies conducted from 1979 to 1991.

Details of the studies are not presented in this paper.

Symptoms of the Disease

Usually, the first observed symptom of sapstreak is a

distinctive "transparency" of the tree crown--a consequence of

unusually small leaves, especially in upper branches but

sometimes over the entire crown (Fig. 1). Often, these small

leaves are normal in color, shape, and number the first year of

the disease, but become off-colored and sparse in subsequent

years. Branch dieback often occurs where small leaves had

occurred the previous year, and this pattern of small leaves

one year followed by death of supporting twigs and branches

the next, can continue for several years until the tree dies (Fig.

2). Sometimes, however, symptom progression is arrested

and results in trees whose upper crowns exhibit branch

Figure 2.--Progressive branch dieback may occur over

several years.

1
dieback or even major stagheading while lower branches are Inside the tree the diseased wood of roots and lower stems

fully foliated with leaves of normal size and color. Some of exhibits a distinctive stain (Fig. 3). Freshly exposed, the stain

these trees recover with no further disease progression while is greenish yellow to yellow-tan with red flecks and appears

others, after several years of apparent remission, again exhibit watersoaked. Often, in cross-section, the stain columns

symptoms. appear to radiate outward and are bordered by a thin,

intermittent, dark-green margin. Soon after exposure, the stain

darkens dramatically, then later fades to a light brown.

Figure 3.--Sapstreak disease stain, when fresh, has a

watersoaked, greenish-yellow-to-tan color with scattered red

flecks, and is bordered by a narrow green margin. The stain

often appears to radiate outward.

External symptoms are related closely to development of

internal stain. By the time crown symptoms appear, stain

columns are well established (Fig. 4), especially in root tissues,

and usually can be revealed by an ax cut into the buttress

roots. In many trees, especially those in remission of crown

symptoms, the outward extension of stain columns appears to

be limited by newly-formed rings of healthy sapwood (Fig. 5).

When trees infected by sapstreak disease are cut into lumber,

the stain columns often are very noticeable and distinctive

(Houston 1986). Within a few minutes of cutting and exposure

to air, stain columns become dark brown (Fig. 6). As drying

progresses, the columns gradually change color, becoming

lighter--while the clear wood, in contrast, darkens (Fig. 7).

Surface planing of dried lumber reverses these patterns and

again reveals the light brown stain of diseased wood in

contrast to the clear, white, healthy wood.

Figure 4.--Well developed stain columns at the root collar and

occupying most of the sapwood. By the time the crown

symptoms appear, the stain is well established.

Figure 5.--Internal stain column that is well

compartmentalized by annual ring boundaries.

2
Figure 6.--Boards cut from the log of a sapstreak diseased

tree. Note extensive columns of dark discoloration.

When C. virescens grows on board surfaces, where it

sometimes sporulates, it usually occurs near the outer margins

of the stain columns and often on clear wood immediately

adjacent to stain columns (Fig. 7). The dark, smudgy

appearance of the fungal growth is distinctive and develops

within a few days of sawing. As drying continues, the surfaces

of the sapstreak stained columns become heavily colonized by

numerous common molds; clear wood remains free of such

growths (Fig. 7).

Disease Development within Individual Trees

Infection and Importance of Wounds

Infection occurs primarily through wounds to the roots, buttress

roots, or the lower portion of stems near the ground during

logging, saphauling, or other activities (Figs. 8, 9) (Hepting

Figure 7.--As drying progresses, the dark stain columns fade

to a light greyish tan (right side or board) and healthy tissues

gradually darken (left side of board). Note the dark smudgy

strip where C. virescens (large arrow) has grown out onto

wood surface near the edge of the stain column, and the

blotchy colonies of saprophytic mold fungi (small arrows)

growing exclusively on the sapstreak diseased wood.

Figure 8.--Basal injuries typical of those on sapstreak

diseased trees adjacent to skid trails.

3
Figure 9.--Buttress roots and roots close to the soil surface

typical of those damaged by traffic in the sugar bush; these

roots are at risk to infection by the sapstreak fungus.

1944, Houston 1992, Meilke and Charette 1989). Stump

wounds, created when sprout members are removed in

thinning, can provide the fungus access to otherwise

unwounded residual members (Fig. 10). A few cases have

been observed where the fungus apparently entered the tree

through roots injured by cattle trampling.

Injuries associated with sapstreak are nearly always close to

the ground. Even though stem tissues can be infected, and

invasion of upper portions of stems from infections originating

in the roots or stem bases can occur, no definitive cases have

been found where infection has occurred naturally through

broken branches or other wounds of upper crowns or stems.

No cases have been observed where, in practice, tapholes

have become infected by sapstreak, and only rarely (2 of 142

ti mes) did this occur when the fungus was placed

experimentally into tapholes (Houston 1992). In each instance

where infection did occur, its development around tapholes

was sharply limited by the tree (Fig. 11).

Results from several studies suggest that wounds made in the

late spring and early summer may be more readily infected by

C. virescens than wounds made at other times. Other tree

species are known to be most susceptible to vascular

pathogens at this time. Meilke and Charette (1989) found no

significant differences in the number of trees affected by

sapstreak in Wisconsin stands logged during frozen versus

nonfrozen conditions, although no records were available

concerning the number of trees wounded or the actual

conditions of the roadways when logging occurred.

A few cases have been observed where the fungus moved

across functional root grafts from wounded, diseased trees to

adjacent, nonwounded neighbors (Houston 1991).

Figurel O.--The injury created when one member of a sprout

clump was removed served as an infection court for the

sapstreak fungus. Note sapstreak stain revealed by the ax

cut at the root collar of the tree.

Disease Progression within Individual Figure 11.--A rare instance of sapstreak disease when the

Trees (Patterns and rates) fungus was placed in the taphole (arrow); the fungus was

contained by the tree and discolored columns were limited.

Within individual trees, the appearance of initial crown Spread probably attributable to tangential orientation of the

symptoms and the rate of their progression varies greatly. taphole, which cut across normally effective ray boundaries.

4
Some trees exhibit severe crown dieback for many years

before they die, while others become symptomatic and

succumb rapidly, often within 2-3 years. Trees that die quickly

and possess severe symptoms usually are extensively

invaded by C. virescens (Fig. 12). In most such trees, vascular

staining is present throughout the roots and much of the

stems, and the fungus sometimes can be isolated from xylem

tissues in the upper portions of stems, often up to 30-45 ft.

Sometimes disease progression, as revealed externally by

crown symptoms, is arrested and recovery ensues, even in

trees with more than 40 percent crown dieback. Some trees

with root-stain patterns characteristic of sapstreak disease

never developed severe foliar symptoms during the course of

a 10-year study. In such trees, the columns of discoloration

usually appear strongly restricted by the tree (Fig. 13).

Figure 12.--Bolts, 1 meter long, sequentially cut (from root

collar up and placed in that order for photo) from a tree that

died within 18 months after being infected with C. virescens.

The dark fungus has grown out from the columns of stained

xylem onto the cut ends of the bolts.

Disease development within trees also can be monitored

nondestructively. Sapstreak stained wood characteristically is

very low in electrical resistance (ER) (50 K ohms and often as

low as 5 to 10 K ohms) compared to healthy tissue (100-700 K

ohms) (Houston and Schneider 1982). Tissues infected by

sapstreak disease can be identified reliably by their ER

measurements (Table 1) 1.

I

Electrical resistance was measured with a Shigometer

(Model OZ-67, Osmose Wood Pres. Co., Buffalo, New York)

and twisted wire probe) (Shigo and Shigo 1974). The method

utilized the fact that as wood becomes discolored, cations

increase in concentration and electrical resistance decreases

(Tattar et al. 1972). Holes 2.4 mm in diameter are drilled to

depths of from 2 to 4 inches in up to four buttress roots on

opposite sides of the tree. The probe is inserted and

resistance readings are taken at 0.25-inch intervals.

Figure 13.--In this tree both developing columns of

discoloration are limited strongly by compartmentalization.

Table 1.--Comparison of electrical resistance (k-ohms) of buttress-root tissues of a healthy tree and a tree with

sapstreak disease

Electrical resistance (K ohms) - July 1980

Depth (inches) into root wood

Root .25 .50 .75 1.0 1.25 1.50 1.75 2.0

1 180 190 210 290 260 230 240 200

Healthy 2 250 230 160 210 256 200 260 260

tree 3 500 400 330 280 280 500 300

4 320 220 230 240 240 250 340 500

1 21 34 18 27 22 46 21

Diseased a 2 15 18 23 17 13 13 9

tree 3 80 80 70 80 70 -

4 100 80 70 90 50 60

aThe tree had severe crown symptoms in 1980 and was still alive in 1981.

5
Development of the disease usually is more rapid and

extensive in roots than stems. Often, extension of the stain

columns into stems is sharply limited even when roots and root

collar regions are severely colonized (Fig.14). Repeated

measurements on individual trees reveal the disease pattern in

a sugar maple root system, July 1980 to July 1981 (Table 2).

Figure 14.-- Sometimes spread of the fungus upward into stem

tissues is limited even though tree roots and root collars are

severely colonized.

Table 2.-- Electrical resistance in two successive years

in buttress roots on different sides of a diseased tree

reveal progression of the disease. Numbers below 50

indicate sapstreak disease.

Tree 68: Electrical resistance (k-ohms) of buttress roots

Depth (Inches into rootwood)

Date Side of

measured tree .25 .50 .75 1.0 1.25 1.50 1.75 2.0

July 1980 N 24 45 35 110 80 35

Symptoms

in W 500 500 450 380 300 500 500 -

extreme

top S 450 250 180 170 250 190 380 200

E 40 100 130 150 110 110 190 80

July 1981 N 55 60 70 60 55 65

Symptoms

same as W 100 175 45 40 40 38 40 -

1980 S 140 180 280 280 210 220 220 190

E 20 12 12 8 7 6 5 4

Speed and extent of column discoloration may relate to the

severity and orientation of infection court and other wounds

near expanding columns. In some trees, dramatically and

greater discoloration occurs when fungus invades deep

wounds across the tangential face of the tree stem or root,

compared to wounds oriented toward the center. Deep

tangential wounds disrupt more preestablished compartment

barriers (Shigo 1977, 1979). In some trees, however, the

fungus is limited regardless of the wound orientation,

suggesting that trees vary in retarding the invasion process.

Finally, other organisms appear to influence the rate at which

sapstreak diseased trees succumb. Trees dying of sapstreak

disease almost always are colonized at their roots or root

collars by Armillaria sp. (Fig. 15), Xylaria sp. (Pers.: Fr. )

Grev. (Fig. 16) , or, rarely, both (Hepting 1944, Houston

1985). These root fungi, ubiquitous inhabitants of long

Figure 15.--The thin, white, girdling mycelial "fan"

of shoestring root rot fungus, Arm/I/aria sp.,

beneath the bark of sapstreak infected tree.

Figure 16.--The fruiting structures of Xylaria sp., a root decay

fungus often found on trees dying from sapstreak disease,

evoke its common name "dead man's fingers."

6
established maple stands, are maintained in root systems of

stumps and dead trees. Root system "food bases" of large

trees probably are more important for longer survival and vigor

of root pathogens than are those of small trees whose roots

are more quickly consumed. Although their actual role in

sapstreak disease has not been demonstrated, it is likely that

these fungi contribute significantly to the death of sapstreak

affected trees.

The ability of Armillaria spp. to invade and kill trees weakened

by stress factors, especially insect defoliation, is well known

(Wargo and Shaw 1985) . Presence of these pathogens and

perhaps others, such as Hypoxylon deustum (Hoffm.: Fr.)

Grev. and Ganoderma applanatum (Pers.) Pat., on dying trees

and their apparent absence from severely affected, but

recovering trees, suggests that their attacks may determine

which sapstreaked trees die or recover.

Severely affected trees often are attacked by Ambrosia

beetles. Initial concentrations usually are near the buttress

roots and lower bole with columns of sapstreak discoloration

near the cambium (Fig. 17). The role of these insects or their

fungal associates in the disease is not known; their great

abundance in later stages of disease suggests they hasten the

demise of diseased trees.

Figure 17.--Long streaks (between vertical split and arrow) of

sapwood discolored by sapstreak disease sometimes occur

near the cambium. The cambium touched by these streaks

dies, and cankers (not yet obvious in this recently infected

sampling) may form. Often, Ambrosia beetles penetrate

these areas into the underlying sapwood (arrow).

Disease Development in Sugarbushes

In sugarbushes, sapstreak disease rarely results in large

numbers of trees dying at one time. Rather, it appears to

affect a few trees, now and again. The following description is

based on observations in many different bushes, in particular,

those made annually over 11 years in two typical sugarbushes

in northern New York.

In sugarbushes, sapstreak disease is not related directly to the

tapping process but to associated activities that result in

wounds to roots and lower stems. Vehicles or equipment that

bruise or cut shallow or buttress roots to expose sapwood

appears the most important factor. The close association of

sapstreak diseased trees to roads used for saphauling in a

New York sugarbush is shown in Figure 18.

Figure 18.--Locations of sapstreak diseased trees (boxed

outlines) and the years when symptoms were first observed

in a New York sugarbush. Main access and saphauling

roads (dash lines) lead to the sugarhouse near plot 6.

1983

1981 Plot 6

1982 1978

4

981

1985

Plot 5

1982 1982

1980

1985

.-1988 Plot 7

1989

Plot 2

1979 v

1983

1979

Plot 3

Plot 4

1984

100 feet

1983

1983

1988

1982

1983

Plot 1

1979

7
In other sugarbushes, sapstreak disease has occurred in trees 

with roots injured by cattle and by log skidding. In one 

instance, a tree, located adjacent to a field, developed 

sapstreak symptoms a few years after its roots had been 

injured when the field was plowed and disked. 

Whether the injuries that led to sapstreak disease were made 

during saphauling or at some other time is not known. The 

fact that very few cases of sapstreak have been observed in 

sugarbushes employing tubing collection systems could be 

due either to reduced saphauling traffic or to less traffic at 

other times. Regardless of the sap collection system used, the 

disease often is most severe near the sugarhouse where traffic 

and other activities are concentrated (Fig. 19). Other factors, 

including a possible buildup of the pathogen on wood from 

contribute to infection of nearby wounded trees. The fungus 

often is found colonizing (Fig. 12) recently cut surfaces of 

stumps and logs (Ohman and Kessler 1963, Shigo 1962). 

Disease Development in Forest Stands 

In forest stands as in sugarbushes, sapstreak diseased trees 

usually have severely injured roots or lower stems. The 

patterns of occurrence in forest stands, however, usually differ 

from those in sugarbushes in ways that reflect the less 

frequent, but more severe, wound-inflicting disturbance 

associated with harvesting operations. In the area within a 

harvested stand in northern New York that was near the log 

landing, 27 trees were found with sapstreak disease in 1985 

(Fig. 20). All of these trees were immediately adjacent to skid 

diseased trees stacked near the sugar house, also may 

Sapstreak diseased ,& trees 

15 ,: : 

I 

1 

I Plot 6 Healthy tree 

Diseased tree 

O Stump 

Stump, sapsfreak 

Figure 19.--Plot 6 in a New York sugarbush. Numbered 

trees (large solid circles) became diseased during the 

decade of observation (1 980-1 990). 

Figure 20.- Locations of sapstreak diseased trees in a forest 

area in northern New York, a portion of which was logged in 

1981. 
Figure 21.--Locations of sapstreak diseased trees in a 30-acre

portion of a forest stand in northern New York. The stand was

thinned in 1980. Trees not dead by 1990 are in remission and

appear to have recovered

trails created when the stand was logged in early summer of

1981. This "flush" pattern, in which a large number of

diseased trees occurs at one time (from infection of wounds

during heavy skidding activity), is in contrast to the occasional

infection of trees in some sugarbushes, in which annual, but

less damaging, intrusions into the stand may result in new or

repeated wounding of additional trees.

In forest stands, sapstreak diseased trees usually exhibit

initial symptoms from 3 to 6 years after the injury-causing

event. While the period over which diseased trees dies

frequently is more protracted, the trees that are going to die

will have done so within 6 to 8 years after they became

infected.

In less heavily trafficked areas within forest stands, or in

stands where fewer trees are being harvested, for example, in

improvement cuts or light thinnings, fewer trees are apt to

become injured and diseased (Fig. 21). In general, diseased

trees often are concentrated in wet areas where roots are

more severely damaged. Residual members of thinned

sprout clumps occasionally are infected by the sapstreak

fungus, apparently through the stump wounds created by the

thinning (Figs. 10, 21).

The following relationships, gleaned from our observations

and studies and from earlier work by others, are pivotal to the

development of management guidelines to prevent or reduce

losses from sapstreak disease in sugarbushes and forest

stands.

• There is an almost universal association of wounds and the

occurrence of sapstreak disease. The disease rarely occurs in

nonwounded trees (see Forest Stands).

Location

Wounds of great importance are those near the ground--roots,

buttress roots, and lower stems.

Wounds of little or no importance are those of branches and

upper stems--branch stubs, pruning wounds, and tapholes.

Causes

Activities that result in wounds (in order of importance) include

skidding logs, hauling sap and wood, building and maintaining

roads, thinning sprout clumps, and trampling by cattle.

Timinq

Wounds made during spring and early summer may be more

important than those made at other times.

Wounded trees, on rare occasion, become diseased when the

sapstreak pathogen invades their roots through functional root

grafts with closely adjacent diseased trees.

Trees that die of sapstreak disease also almost always are

invaded by root pathogens, especially Armillaria sp. and

Xylaria sp.

These relationships are reflected in the following management

options and guidelines for reducing losses from sapstreak

disease in sugarbushes and forest stands,

Management Options and Guidelines to

Reduce Losses from Sapstreak Disease

Sugarbushes

Reduce infection courts

• Avoid wounding of roots, buttress roots, and lower portions

of the stem.

• Employ tubing collection systems when feasible.

• Use permanent access and haul roads.

• Avoid travel with heavy equipment during spring-early

summer mud season and wet periods.

Avoid creating other infection courts

• When conducting thinnings or stand improvement operations

either leave or take all members of sugar maple sprout

clumps.

Avoid susceptible period

• Conduct thinnings, stand improvement operations, wood

hauling, and other activities that may result in injuring trees, in

late summer, fall, and winter when trees seem to be less

susceptible to infection.

- Tree with sapstreak

)- Dead tree, 1990

S • - Tree with "stump" wound

- -

--

T

',v,, t

Low, wet area .21

/

Upland area

S

S I;'

Low, wet area w

100 m

Skid trails

Road

9
Avoid build-up of sapstreak disease inoculum

• Monitor sugarbush to detect diseased trees.

• Concentrate surveys to trees along roadways and near

sugarhouse.

• Remove diseased trees promptly (see above for best

periods).

• Avoid stacking infected wood near the sugarhouse. If

possible, dry diseased wood in large open areas away from

areas where trees are apt to be injured.

Reduce threat from mortality-associated root pathogens

• Ideally, establish sugarbush at early age to reduce the need

to remove large trees in later thinnings and consequently

reduce large stump food bases for root decay organisms.

• Monitor sugarbush to track populations of defoliating insects.

When necessary, arrange to control outbreaks of insects

whose effects will predispose trees to invasion by root

pathogens.

Forest Stands

Reduce infection courts

• Avoid wounding roots, buttress roots, and lower portions of

stems.

• Establish permanent skid trails and haul roads. If possible,

use trees other than sugar maple as bumper trees.

• Schedule forest operations to avoid mud season or periods

when soil is saturated and soft.

• For stands rich in sugar maple, schedule operations to avoid

the late spring-early summer period when trees appear to be

most susceptible.

• Don't thin sugar maple sprout clumps that are pole-sized or

larger--leave them all or remove them all.

Reduce effects of associated root pathogens

• Monitor climatic factors such as open, cold winters; drought;

late spring frosts; and biotic factors such as insect defoliator

outbreaks known to predispose trees to root pathogens.

• When possible, schedule forestry operations to avoid

conducting them during, or soon after, stress events.

Reduce inoculum and losses

• Revisit stands 4 to 5 years after logging operations to monitor

the occurrence of sapstreak.

• Focus surveys on trees adjacent to skid trails or landings,

and especially on those trees with basal skidding injuries.

• If feasible, remove diseased trees taking care not to create

additional new injuries. (See infection courts above).

Literature Cited

Beil, J. A. ; Kessler, K. J., Jr. 1979. Sapstreak disease of

sugar maple found in New York State. Plant Disease

Reporter. 63: 436.

Hepting, G.H. 1944. Sapstreak, a new killing disease of

sugar maple. Phytopathology. 34: 1069-1076.

Houston, D.R. 1985. Sapstreak of sugar maple: How

serious is it? Maple Syrup Digest. 25(2): 24-27.

Houston, D.R. 1986. Sapstreak of sugar maple:

appearance of lumber from diseased trees and longevity

of Ceratocystis coerulescens in air-dried lumber.

Phytopathology. 76: 653. Abstract.

Houston, D.R. 1991. Spread of the sugar maple sapstreak

disease pathogen, Ceratocystis coerulescens, via root

grafts between Acer saccharum. Phytopathology. 81: 122.

Abstract.

Houston, D.R. 1992. Importance of buttress root and

taphole wounds as infection courts for the sugar maple

(Acer saccharum) sapstreak pathogen, Ceratocystis

coerulescens. Phytopathology. 82: 244. Abstract.

Houston, D.R.; Fisher, K.D. 1964. Sapstreak of sugar

maple found in the northeast. Plant Disease Reporter. 48:

788.

Houston, D.R.; Schneider, B. 1982. Sapstreak disease of

sugar maple in N.Y. sugarbushes. Phytopathology. 72:

262. Abstract.

Kessler, K., Jr. 1972. Sapstreak disease of sugar maple

found in Wisconsin for the first time. Res. Note NC-140.

St. Paul, MN: U.S. Department of Agriculture, Forest Service,

North Central Forest Experiment Station. 2 p.

Kessler, K., Jr. 1978. How to control sapstreak disease of

sugar maple. St. Paul, MN: U.S. Department of Agriculture,

Forest Service, North Central Forest Experiment Station. 5 p.

10
Kessler, K., Jr.; Anderson, R.L. 1960. Ceratocystis

coerulescens on sugar maple in the Lake States. Plant

Disease Reporter. 44: 348-350.

Meilke, M.E.; Charette, D.A. 1989. The incidence of

sapstreak disease of sugar maple in Menominee County,

Wisconsin, and its relationship to wounds and season of

logging, Northern Journal of Applied Forestry. 6: 65-67.

Ohman, J.H.; Kessler, K.J., Jr. 1963. Current status of the

sapstreak disease of sugar maple in the Lake States. Res.

Note LS-10. St. Paul, MN: U.S. Department of Agriculture,

Forest Service, Lake States Forest Experiment Station. 4 p.

Shigo, A.L. 1962. Observations on the succession of

fungi on hardwood pulpwood bolts. Plant Disease

Reporter. 46: 379-380.

Shigo, A.L. 1977. Compartmentalization of decay in trees.

Agric. Inf. Bull. No. 405. Washington, DC: U.S. Department

of Agriculture, Forest Service. 73 p.

Shigo, A.L. 1979. Tree decay: an expanded concept.

Agric. Inf. Bull. No. 419. Washington, DC: U.S. Department of

Agriculture, Forest Service. 73 p.

Shigo, Al.; Shigo, A. 1974. Detection of discoloration and

decay in living trees and utility poles. Res. Pap. NE-294.

Upper Darby, PA: U.S. Department of Agriculture, Forest

Service, Northeastern Forest Experiment Station. 11 p.

Tattar, T.A.; Shigo, Al.; Chase, T. 1972. Relationship

between the degree of resistance to pulsed electric

current in wood in progressive stages of discoloration

and decay in living trees. Canadian Journal of Forest

Research. 2: 236-243.

Wargo. P.M.; Shaw, C.G., III. 1985. Armillaria root rot. The

puzzle is being solved. Plant Disease. 69: 826-832.

11
Houston, David R. 1993. Recognizing and managing sapstreak disease of

sugar maple. Res. Pap. NE-675. Radnor, PA: U.S. Department

Agriculture,Forest Service, Northeastern Forest Experiment Station. 11 p.

Sapstreak disease, a potentially serious problem of sugarbushes and forest

stands, occurs when the causal fungus, Ceratocystis virescens, invades the

sapwood of roots and bases of stems through wounds inflicted during logging,

saphauling, or other activities. Describes how to recognize the disease, the

factors that affect its occurrence and development, and management

approaches to help reduce its effects.

Keywords: Ceratocystis virescens, root and buttress-root wounds, vascular

disease, sugarbush, forest management.

U.S. GOVERNMENT PRINTING OFFICE: 1993/752-494/
Headquarters of the Northeastern Forest Experiment Station is in Radnor, Pennsylvania. Field laboratories are maintained at:

Amherst, Massachusetts, in cooperation with the University of Massachusetts

Burlington, Vermont, in cooperation with the University of Vermont

Delaware, Ohio

Durham, New Hampshire, in cooperation with the University of New Hampshire

Hamden, Connecticut, In cooperation with Yale University

Morgantown, West Virginia, in cooperation with West Virginia University

Orono, Maine, in cooperation with the University of Maine

Parsons, West Virginia

Princeton, West Virginia

Syracuse, New York, in cooperation with the State University of New York,

College of Environmental Sciences and Forestry at Syracuse University

University Park, Pennsylvania, in cooperation with The Pennsylvania State University

Warren, Pennsylvania

Persons of any race, color, national origin, sex, age, religion, or with any handicapping condition are welcome to use and enjoy all facilities, programs, and services of

the USDA. Discrimination in any form is strictly against agency policy, and should be

reported to the Secretary of Agriculture, Washington, DC 20250.

" Caring for the Land and Serving People Through Research"