Turfgrass Disease Compendium

Turfgrass
Disease Compendium
By Cameron Stephens, Eric
Brackman, Jordan Schmidt, Matt
Green, Tyler Kossow, William Jones
Plant Pathology 3001, Fall 2013
1
Turfgrass, Poa ssp.
2
Diseases of Turfgrass
• Bacterial pathogens
– Xanthomonas campestris
– Acidovorax avenae
• Fungal and fungal-like pathogens
– Oomycete:
• Sclerophthora macrospora
– Ascomycetes:
• Blumeria graminis
• Pyricularia grisea
3
Diseases of Turfgrass, cont’d
• Fungal pathogens, continued
– Basidiomycetes:
• Laetisaria fuciformis
• Typhula incarnata
• Viral pathogen: Panicum mosaic virus
• Pathogenic nematodes
– Hoplolaimus galeatus
– Xiphinema americanum
4
Diseases of Turfgrass cont’d
• Extra credit pathogens:
– Barely yellow dwarf virus
– Erysiphe graminis
– Sclerotinia homoeocarpa
– Pythium aphanidermatum
5
Viruses of Turfgrass
• Panicum mosaic virus cause
of St. Andrews Decline
• Barley yellow dwarf virus cause of
Barley yellow drawf
6
Panicum mosaic virus cause of
St. Andrews Decline
• Conducive environment:
– Areas where non-resistant varieties of St.
Augustinegrass are present
• Symptoms:
– Mosiac
– Mottling
– Chlorosis
• Signs:
– Look under microscope for virus
7
Panicum mosaic virus cause of
St. Andrews Decline
Dispersal by
machinery
Infection
court is
opening in
blade of
grass
Virus colonizes
and spreads
creating circular
spots
Primary
Inoculum is
infected RNA
Overwinters in
infected sap
The grass
slowly becomes
necrotic and
dies
8
Panicum mosaic virus cause of
St. Andrews Decline
• Diagnosis
– Observe grass chlorotic mottling between a
1-3 year span
• Management tactics
– Use resistant strands of turfgrass
– Clean mowers regularly by using a 10%
solution of bleach
9
Panicum mosaic virus cause of
St. Andrews Decline
• References:
– Landscspe-america.com
– Essential Plant Pathology- Second Edition
– Smiley, Richard W., Peter H. Dernoeden, and
Bruce B. Clarke. Compendium of Turfgrass
Diseases. 3rd ed. Vol. 2. St. Paul, MN: APS,
2005. Print.Schumann, Gail L., and Cleora
D'Arcy. Essential Plant Pathology. 2nd ed. St.
Paul, MN: APS, 2006. Print
10
Barley yellow dwarf virus cause
of Barley yellow dwarf
• Conducive environment:
– High light intensity and temperatures between
59-65⁰F
• Symptoms:
– Stunting
– Root mass reduced
– Loss of green in leaves (yellowing)
• Signs:
– Look under microscope for virus
11
Barley yellow dwarf virus cause
of Barley yellow dwarf
12
Barley yellow dwarf virus cause
of Barley yellow dwarf
• Diagnosis
– Enzyme-linked immunosorbent assay or
ELISA testing
• Management tactics
– Using tolerant or resistant cultivars
– Catching the aphid vectors in traps
13
Barley yellow dwarf virus cause
of Barley yellow dwarf
• References:
– Apsnet.org
– Essential Plant Pathology- Second Edition
– Smiley, Richard W., Peter H. Dernoeden, and
Bruce B. Clarke. Compendium of Turfgrass
Diseases. 3rd ed. Vol. 2. St. Paul, MN: APS,
2005. Print.Schumann, Gail L., and Cleora
D'Arcy. Essential Plant Pathology. 2nd ed. St.
Paul, MN: APS, 2006. Print
14
Fungal and fungal-like
pathogens of turfgrass
• Ascomycetes or imperfects:
– Sclerotinia homoeocarpa, cause of Dollar
Spot
– Pyricularia grisea, cause of Gray Leaf Spot
Sclerotinia homoeocarpa, cause
of Dollar Spot
•
•
•
Conducive environment:
– Prolonged period of high humidity in the canopy are required
– Disease development occurs under warm/ humid weather with
cool nights that produce heavy dews
– Temperatures from 59-86⁰ F (15-30⁰ C)
– Dry soils with low nitrogen fertility
Symptoms:
– Circular sunken patches of blighted turf that rarely exceed a 2 inch
diameter. If disease becomes severe, large irregular patches form
from combined smaller patches
– Hour-glass shaped lesions across the leaf but can also be oval
shaped. Lesion symptoms develop from chlorotic to water-soaked
and then bleached white with a brown border
– Dieback from the leaf tip is also common
Signs:
– A white, cottony growth of mycelium that disappears
as leaves dry
Sclerotinia homoeocarpa, cause
of Dollar Spot
Sclerotinia homoeocarpa, cause
of Dollar Spot
•
Diagnosis
–
–
–
–
–
–
Take note of the turf species that is present
Look for silver dollar sized spots across the area
Watch for mycelium growth on dewy mornings
New lesions will be oval shaped with a brown border
Older lesions form an hour-glass shape across the leaf
Observe the hyphae under a microscope
•
•
S. homoeocarps does not produce spores
Management tactics
– Avoid low nitrogen fertility in the soil by applying light applications of nitrogen
frequently
– Avoid drought stress on the turf by maintaining soil moisture near field capacity
– Do not water in the evenings because this will allow for overnight wetness of the
leaves
– Remove dew in the mornings
– Do not allow thatch to be greater then .5 inches thick
– Apply fungicides
– Use resistant varieties
Sclerotinia homoeocarpa, cause
of Dollar Spot
• References:
– American phytopathological Society. “Dollar
spot of turfgrass.” APSnet. American
phytopathological Society, 2013. Web. 14
November 2013
http://www.apsnet.org/edcenter/intropp/lesson
s/fungi/ascomycetes/pages/dollarspot.aspx
– Smiley, Richard, Peter Dernoeden, and Bruce
Clarke. 2005. Compendium of Turfgrass
Diseases, 3rd edition. Print.
– Schuman, G. L., and C. J. D’Arcy. 2010.
Essential Plant Pathology, 2nd Edition. St.
Paul, MN: American Phytopathological
Society. 369 pp.
Pyricularia grisea, cause of Gray
Leaf Spot
•
Conducive environment:
– Warm, Humid weather at 82-90⁰F (28-32⁰C)
– Moderate to high nitrogen fertility
– More severe in newly established turf
•
Symptoms:
– In warm season species, tiny brown oblong lesions develop into large lesions
that can reach across the leaf and kill it
– In cool season species, small water-soaked lesions appear which then quickly
become necrotic.
– Lesions often are gray to light brown that are surrounded by purple to dark brown
borders
– Blighted leaf tips have a twisted or fishhook shape
– Irregular shaped patches are formed
•
Signs:
– Thick masses of grayish conidia and conidophores may give leaves a feltlike
appearance
– Conidia can be seen under the microscope
Pyricularia grisea, cause of Gray
Leaf Spot
Pyricularia grisea, cause of Gray
Leaf Spot
• Diagnosis
– Take note of the turf species that is present
– Observe the overall shape of the patches forming. Gray leaf
spot has irregular shaped patches
– Look at the individual lesions on leaves. Gray leaf spot forms
oblong shaped lesions that are tan to gray with a purple or
brown border.
– Observe the affected leaf tissue under a microscope and
look for Pyricularia grisea conidia
• Management tactics
– Limit drought stress, extended periods of leaf wetness,
excessive nitrogen, and soil compaction
– Use slow release fertilizers
– Overseed in late fall when disease outbreaks are less severe
– Apply preventative fungicides
– Use resistant varieties
Pyricularia grisea, cause of Gray
Leaf Spot
• References:
– NC State University. “Gray Leaf Spot.”
Turffiles. 2013. Web. 14 November 2013.
http://www.turffiles.ncsu.edu/diseases/Gray_L
eaf_Spot.aspx
– Smiley, Richard, Peter Dernoeden, and Bruce
Clarke. 2005. Compendium of Turfgrass
Diseases, 3rd edition. Print.
– Schuman, G. L., and C. J. D’Arcy. 2010.
Essential Plant Pathology, 2nd Edition. St.
Paul, MN: American Phytopathological
Society. 369 pp.
Basidiomycete pathogens of Poa
spp.
• Laetisaria fuciformis, cause of Red
Thread
• Typhula incarnata, cause of Typhula
Blight, also known as Gray Snow Mold
Laetisaria fuciformis, cause of
Red Thread
• Conducive Environment:
– Typically spring and autumn, in slow growing, nitrogen
deficient turf during periods of cool and humid weather.
• Symptoms:
–
–
–
–
First observed is brown/tan dead leaves.
Water soaked grass areas.
Circular or irregular shaped dead spots.
Necrosis will progress from leaf tip to base.
• Signs:
– Wet weather – pale red or orange threadlike sclerotia will
protrude from leaf tips.
– Dry weather – brittle, bright red or orange sclerotia
– Humid weather – pink, cottony flocks of mycelium and
mycelial mats will be present.
Laetisaria fuciformis, cause of
Red Thread
Laetisaria fuciformis, cause of
Red Thread
• Diagnosis:
– Circular, irregular yellow patches, 2 to 24
inches, become brown and appear dead.
Affected parts are bound together by a
red/pink/organge web of sclerotia or
mycelium.
• Management Tactics:
–
–
–
–
–
Proper nitrogen applications
Proper watering practices
Provide adequate light and air movement
Removal of grass clippings
Application of fungicides
Laetisaria fuciformis, cause of
Red Thread
• References:
– http://www.turffiles.ncsu.edu/diseases/Red_Threa
d.aspx Center for Turfgrass, Environmental
Research, and Education. North Carolina State
University. Web. 14 November 2013.
– Smiley, Richard W., Peter H. Dernoeden, and
Bruce B. Clarke. Compendium of Turfgrass
Diseases. 3rd ed. Vol. 2. St. Paul, MN: APS, 2005.
Print.
– Schumann, Gail L., and Cleora D'Arcy. Essential
Plant Pathology. 2nd ed. St. Paul, MN: APS, 2006.
Print.
Typhula incarnata, cause of Typhula
Blight, also known as Gray Snow
Mold
•
Conducive Environment:
•
Symptoms:
•
Signs:
– Any area of grass with a wet canopy, on unfrozen soil, covered by
snow for extended periods of time.
– Temperatures just above freezing (up to 35 degrees).
– Deep snow will promote favorable conditions for longer periods of time.
– High amounts of nitrogen fertilizer.
– At snowmelt, circular areas of light yellow, straw colored, or grayish
brown turf.
– Matted areas of leaves, that turn grayish to white, brittle and matted, as
the area dries.
– Necrosis of leaves.
– White to gray mycelium
– Small, hard, and spherical sclerotia form on infected leaves.
– Sclerotia - white/pink/amber when young, and red/brown/black when
mature
Typhula incarnata, cause of Typhula
Blight, also known as Gray Snow
Mold
Typhula incarnata, cause of Typhula
Blight, also known as Gray Snow
Mold
• Diagnosis:
– The primary diagnostic feature of gray snow mold is
the presence of small sclerotia. These are embedded
in the leaves and crowns of the infected grass plants.
• Management Tactics:
– Primary control of snow mold is by application of
fungicides before the first snow of the year.
– Avoid heavy nitrogen applications late in season.
– Mow grass shorter to prevent a tall canopy.
– Avoid creating long lasting snow piles.
– Remove thatch and alleviate compaction.
– Remove snow as soon as possible to promote drying.
Typhula incarnata, cause of Typhula
Blight, also known as Gray Snow
Mold
• References:
– http://plantscience.psu.edu/research/centers/turf/extension/f
actsheets/managing-diseases/gray-snow-mold
College
of Agricultural Sciences. Penn State University, Department
of Plant Science. Web. 14 November 2013
– Smiley, Richard W., Peter H. Dernoeden, and Bruce B.
Clarke. Compendium of Turfgrass Diseases. 3rd ed. Vol. 2.
St. Paul, MN: APS, 2005. Print.
– Schumann, Gail L., and Cleora D'Arcy. Essential Plant
Pathology. 2nd ed. St. Paul, MN: APS, 2006. Print.
Plant Parasitic Nematodes of
Turfgrass
• 1) Xiphinema americanum - Dagger
nematode
• 2) Hoplolaimus galeatus - Lance nematode
Xiphinema americanumDagger Nematode
•
•
•
Conducive environment:
- Abundant oxygen
- less disturbed sites
- Abundant vegetation
- > 45 cm of rainfall
Symptoms:
- little aerial symptoms
- root swelling
- sunken, redish-brown lesions on roots
- Stunting, chlorosis, wilting, root necrosis
- overall reduced root system
Signs:
- Galls on the root tips
- Hypertrophy
Molting does
not occur in
the egg and
the first
stage
hatches.
Xiphinema americanumDagger Nematode
QuickTime™ and a
Ectoparasite
decompressor
QuickTime™
and a
are needed
to see this picture.
decompressor
are needed to see this picture.
Ectoparasite
Xiphinema americanumDagger Nematode
• Diagnosis: (Send soil sample including roots to qualified
personnel)
-Soil extraction method-- Measure
dimensions of nematode
- Ex: Females- Vulva at 46-54% of body length,
adults range in length from 1.3 to 2.2 mm
- Sieving and Sucrose-Centrifugation
• Management Tactics:
- Frequent till
- Limit runoff and standing water(keep soils dry
- Nematicides (5% will still remain)
- bare soil fields for 2 years
Xiphinema americanumDagger Nematode
References
• Smiley, Richard. Compendium of Turfgrass
Diseases. 3rd. St. Paul: APS Press, 2005.
117-122. Print.
• Ferris, Howard. " Xiphinema americanum."
Davis, California: 2013.
<http://plpnemweb.ucdavis.edu/nemaplex/tax
adata/G143S1.HTM>.
• Class notes- Oct.23 Nematology lecture
Hoplolaimus galeatus
Lance nematode
•
Conducive environment:
-Warm
-High moisture
-Medium compaction
–
Symptoms:
- Vascular tissue damage
- Root necrosis
- limited root systems
- Chlorosis, stunting, wilting, defoliation
–
Signs:
- Nematode present in soil
- Dying roots
Hoplolaimus galeatus
Lance nematode
QuickTime™ and a
Endoparasite
Endoparasite
and
decompressorand
QuickTime™
a
are needed to
see this picture.
decompressor
are needed to see this picture.
ectoparasite
and
Ectoparasite
Hoplolaimus galeatus
Lance nematode
• Diagnosis (Send soil sample including roots to qualified
personnel)
-Soil extraction method-- Measure dimensions of nematode
-Ex: Relatively large adults 1.1-15.mm, males are
smaller than females, body is slightly curved when
relaxed
- Sieving and Sucrose-Centrifugation
• Management tactics:
- Chemical control is relatively ineffective
- Deep watering
- Raise mowing height
- Limit traffic
- Chemical “dipping”
Hoplolaimus galeatus
Lance nematode
• Crow, William. "Featured Creatures." Lance Nematode. (2001):
n. page. Web. 14 Nov. 2013.
<http://entnemdept.ufl.edu/creatures/nematode/lance_nematode
.htm>.
• Smiley, Richard. Compendium of Turfgrass Diseases. 3rd. St.
Paul: APS Press, 2005. 117-122. Print.
• Johnson, A.W. "Control of the Lance Nematode, Hoplolaimus
galeatus, on 'Tifdwarf' Bermudagrass by Chemical Dips."
Journal of Nematology. 2.2 (1970): n. page. Print.
Ascomycete Pathogens of
Poa spp.
• Colletotrichum spp., cause of
Anthracnose
• Blumeria graminis, cause of Powdery
Mildew
Colletotrichum spp., cause of
Anthracnose
• Conducive Environment:
- Air temperature 80-95
- High humidity
- Poor Fertility
- Excess thatch
• Symptoms:
- Basal rot that girdles leaf, stem may blacken
- Lesions on older leaves, crown rot
• Signs:
-Black fruiting bodies on leaf and sheath
Colletotrichum spp., cause of
Anthracnose
Colletotrichum spp., cause of
Anthracnose
• Diagnosis
- Development of blackened fruiting bodies
on the leaves and sheath of the plant.
• Management tactics
- Core aerification
- Dethatching
- Topdressing
- Use of light weight equipment
- Increased nitrogen fertilization
- Sufficient irrigation
- Use of fungicides
Colletotrichum spp., cause of
Anthracnose
• References:
Schumann, Gail L., and Cleora J. D'Arcy. "What Are the Causes of Plant Diseases?" Essential Plant Pathology.
St. Paul, MN:
APS, American Phytopathological Society, 2006. 27-28. Print.
Gardner, Dave. Turfgrass Management. Columbus, OH: The Ohio State University.
Settle, Derek M., Alfredo D. Martinez-Espinoza, and Lee L. Burpee. "Anthracnose of Turfgrass." Anthracnose of
Turfgrass. N.p., 2006. Web. 14 Nov. 2013.
Blumeria graminis, cause of
Powdery Mildew
• Conducive Environment:
- Shade
- Poor air circulation
- High Humidity
- Temperature of 62-70
- Excessive fertilization
• Symptoms:
- Underside of leaf turns yellow to tan
- Turf thins in severe cases
• Signs:
- Dull gray-white hyphae on upper leaf surface
Blumeria graminis, cause of
Powdery Mildew
Blumeria graminis, cause of
Powdery Mildew
• Diagnosis:
-Develops dull gray-white hyphae on the
upper leaf surface.
• Management tactics:
- Plant shade tolerant grasses
- Use less nitrogen
- Use less irrigation
- Use higher mowing heights
Blumeria graminis, cause of
Powdery Mildew
• References:
Schumann, Gail L., and Cleora J. D'Arcy. "What Are the Causes of Plant Diseases?" Essential Plant Pathology.
St. Paul, MN:
APS, American Phytopathological Society, 2006. 27-28. Print.
Gardner, Dave. Turfgrass Management. Columbus, OH: The Ohio State University.
"POWDERY MILDEW." Turffiles:Diseases:Powdery Mildew. N.p., n.d. Web. 14 Nov. 2013.
Oomycete Pathogen of
Turfgrass
• Pythium, cause of Pythium blight
51
Pythium, Cause of Pythium
blight
• Conducive environment:
– Warm to hot humid weather, in closely
mowed grasses, especially when wet for at
least 12 hours.
• Symptoms:
– Foliar blight
– Declining turf health
• Signs:
– mycelium growing from infected turfgrass
foliage
52
Pythium, Cause of Pythium
blight
53
Pythium, Cause of Pythium
blight
• Diagnosis
– Non-septate hyphae
– turf will collapse and appear brown and
matted
• Management tactics
– Water management
– Fungicide application
– A preventative fungicide program is
recommended
54
Pythium, Cause of Pythium
blight
• References:
– Schumann, Gail, and Cleora D'Arcy. Essential Plant
Pathology. 2nd. St. Paul : APS Press, 2010. Print.
– Allen, T.W., A. Martinez, and L.L. Burpee. apsnet. The
American Phytopathological Society, n.d. Web. 15 Nov
2013.
<http://www.apsnet.org/edcenter/intropp/lessons/fungi/Oomy
cetes/Pages/PythiumBlight.asp&xgt;.
– Smiley, Richard, Peter Dernoeden, and Bruce Clarke.
Compendium of Turfgrass Diseases. 3rd. St. Paul: Allen,
T.W., A. MartiThe American Phytopathological Society,
2005. Print.
55
Oomycete Pathogen #2
• Sclerophthora macrospora cause of
yellow tuft
56
Sclerophthora macrospora
cause of yellow tuft
• Conducive environment:
•
Periods of cool, wet weather, common in wet, poorly drained areas, and
excessive thatch areas
• Symptoms:
• Small, yellow spots that are scattered across the turf stand.
The yellow spots are slightly raised above the turf canopy.
The affected plants will pull easily from the turf to reveal
dense clusters of yellowed tillers emanating from a single
crown. This profuse tillering is referred to as a witches broom
• Signs:
• S. macrospora produces sporangia on turfgrass leaves.
early in the morning under heavy dew they are pearly white
and give a downy appearance to leaf surfaces when viewed
with a hand lens
57
Sclerophthora macrospora
cause of yellow tuft
58
Sclerophthora macrospora
cause of yellow tuft
• Diagnosis
– S. macrospora produces sporangia on turfgrass leaves.
early in the morning under heavy dew they are pearly white
and give a downy appearance to leaf surfaces when viewed
with a hand lens
• Management tactics
– Improve the soil drainage, increase air circulation, use
proper surface contours to minimize water movement and
accumulation on the turf’s surface. Avoid high or excessive
levels of nitrogen that result in lush growth.
– Fungicides containing mefenoxam and metalaxyl are known
to be very effective against yellow tuft. Curative control of
yellow tuft is difficult, so a preventative fungicide program is
reccomended
59
Sclerophthora macrospora
cause of yellow tuft
• References:
– Schumann, Gail, and Cleora D'Arcy. Essential Plant
Pathology. 2nd. St. Paul : APS Press, 2010. Print.
– Tredway, Lane, Gail Wilkerson , Bridget Lassiter , Jennifer
Reynolds, and Gregory Buol. "YELLOW TUFT." NC State
University. Departments of Plant Pathology and Crop
Science, n.d. Web. 15 Nov 2013.
<http://www.turffiles.ncsu.edu/diseases/Yellow_Tuft.asp&xgt
;.
– Smiley, Richard, Peter Dernoeden, and Bruce Clarke.
Compendium of Turfgrass Diseases. 3rd. St. Paul: Allen,
T.W., A. MartiThe American Phytopathological Society,
2005. Print.
60
Bacterial pathogens of turfgrass
Xanthomonas campestris, cause of
Bacterial Wilt of annual bluegrass
Acidovorax avenae, cause of bacterial
wilt of creeping bentgrass
61
Xanthomonas campestris, cause of
Bacterial Wilt
•Conducive environment:
Infects annual bluegrass (Poa annua)
l
–Favors periods of heavy rain; long periods of
overcast, cloudy skies
•Symptoms:
–Quickly wilts and turns reddish brown or yellow
–Severe infection can affect large, non-uniform
areas in a few days
•Signs:
–Under a microscope, rapid oozing of bacterial cells
from vascular bundles
62
Xanthomonas campestris, cause of
Bacterial Wilt
63
Xanthomonas campestris, cause of
Bacterial Wilt
•Diagnosis
–Using a high-power microscope, look for rapid
oozing or streaming bacterial cells from vascular
bundles
•Management tactics
–Copper hydroxide can slow spread of disease
–Mowers should only be used on affected areas and
disinfected after use
–Mow only when it is dry
64
Xanthomonas campestris, cause of
Bacterial Wilt
•References:
Kaminski, J.E. Bacterial Wilt. University of
Connecticut.http://www.turf.uconn.edu/pdf/researc
h/factsheets/Disease_Bacterial_Wilt.pdf
–Smiley, Richard W. et al. Compendium of Turfgrass
Diseases: Third Edition. APS Press, 2005. Print.
–Couch, Houston B. Diseases of Turfgrasses: Third
Edition. Krieger Publishing Company, 1995. Print.
l
65
Acidovorax avenae, cause of
Bacterial Wilt
•Conducive environment:
–Favors periods of heavy rain; long periods of
overcast, cloudy skies
–Host is Creeping Bentgrass (Agrostis stolonifera)
•Symptoms:
–Quickly wilts and turns reddish brown or yellow
–Severe infection can affect large, non-uniform
areas in a few days
–Necrosis from leaf tip down
•Signs:
l
Under a microscope, rapid oozing of bacterial cells
66
Acidovorax avenae, cause of
Bacterial Wilt
67
Acidovorax avenae, cause of
Bacterial Wilt
•Diagnosis
–Using a high-power microscope, look for rapid
oozing or streaming bacterial cells from vascular
bundles
•Management tactics
–Copper hydroxide can slow spread of disease
–Mowers should only be used on affected areas and
disinfected after use
–Mow only when it is dry
68
Acidovorax avenae, cause of
Bacterial Wilt
•References:
Roberts, J. et al. Rutgers University.
http://www.turf.rutgers.edu/research/wpa-tc2013/pa-bacterialdiseases.pdf
–Smiley, Richard W. et al. Compendium of Turfgrass
Diseases: Third Edition. APS Press, 2005. Print.
–Couch, Houston B. Diseases of Turfgrasses: Third
Edition. Krieger Publishing Company, 1995. Print.
l
69