Fairy Ring:
various basidiomycota
• Destroys turfgrass uniformity
• occasionally kills a band of grass at the
active edge of the fungus
• mycellium may cause hydrophobic spots
• mushrooms are unsightly and can “hide”
golf balls
• all grasses are susceptible
Symptoms
• Donut shaped rings or partial rings of
luxuriant, green grass 2’ to several feet and
larger
• over stimulated band is roughly 6” to 12”
wide
• green color and rapid growth are a result of
nitrogen release from organic matter being
decomposed by the fungus
Symptoms
• Grass is adversely affected to varying
degrees ranging from simple asthetic
problems to death of the grass
• edge of ring may “sprout” mushrooms
• “textbook” cases are a result of buried
organic matter
• can be serious problem on new sand based
turfgrass especially golf greens
Fairy ring “phonetics”
• Edaphic
• Type I - dead or
severely damaged
• Type II - dark green
rings
• Type III - little
damage/stimulation
mushrooms present
• Lectophilic
• Type A- little
damage/stimulation
mushrooms present
• Type B - dark green
rings
• Type C - dead or
severely damaged
Activity
• Survive as spores or mycellium
• most active during warm weather
• many cases are perennial (ie. Comes back in
the same spot year after year)
• can cause type I, II, or III symptoms
Control
• If possible remove all old soil and replace
followed by fumigation
• Prostar and Heritage have some activity
• better if injected, wetting agents may help
• in new sand-based greens, use adequate
organic matter, off-site mixing, wait a few
months (if you last that long)
Fairy ring on a Finnish soccer
field
• This field illustrates edaphic fairy ring caused by
high soil organic matter and liberal use of raw
chicken manure for fertilizer.
• Note the dark green color at the edge of the ring.
This is a response to the nitrogen released as
protein in the organic matter is digested by the
fungus and excess N is released.
Fairy Ring with fruiting-bodies
Edaphic fairy ring on
bermudagrass
• Fairy ring is not always circular but can
occur as an irregularly circular arc. When it
reaches the fruiting stage mushrooms are
produced at the active edge of the disease.
• Fairy ring frequently occurs in the same
area year after year.
Lectophilic fairy ring on a
bermudagrass putting green
• This green is low in nitrogen so the ring is
very pronounced. New sand based greens
are especially susceptible to fairy ring
because of reduced competition from other
organisms. Usually the problem disappears
as the soil in the green matures.
Type C symptoms in a
bermudagrass putting green
• Also low in nitrogen this green is exhibiting
what is often termed type C lectophilic fairy
ring. The grass is being killed at the active
edge of the ring.
Hydrophobic spot left by fairy
ring activity
• Although fairy ring usually doesn’t kill
grass it can cause problems in it’s aftermath.
This photo shows a hydrophobic spot left
behind after the active fairy ring
disappeared.
Gaeumannomyces graminis
• bermudagrass decline
• St. Augustinegrass take-all root rot
• also been observed as pathogen of
zoysiagrass
• associated with disease of in
centipdedegrass
• can be confused with brown patch
Gaeumannomyces graminis
• Primarily a root pathogen, has progressed
significantly when secondary foliar
symptoms appear
• starts as small “weak” spot in turf,
progresses to large, irregular, thinning
patches
• leaf symptoms range from chlorosis to
necrosis
Gaeumannomyces graminis
• Patches typically have healthy swards of
turfgrass intermixed
• roots are short and rotted, stolons can be
lifted easily
• likes hot weather and wet to saturated
conditions
• stressed turfgrass is much more susceptible
Gaeumannomyces graminis
•
•
•
•
•
No effective chemical
raise HOC
irrigate properly and correct poor drainage
improve air circulation
some systemic fungicides (Banner,
Bayleton, Rubigan, Fungo, Cleary’s 3336)
may help as preventative
Microscopic view
Gaeumannomyces graminis
• This picture shows hyphopodia, an organ
characteristic of Gaeumannomyces
graminis, attached to grass tissue. The
hyphopodia
hyphopodia
is a modified hypha that
attaches itself to plant tissue and directly
penetrates cells.
Gaeumannomyces graminis on
St. Augustinegrass
• The common name for this disease on St.
Augustinegrass this disease is “take-all
patch”.
• The general thinning shown here is
characteristic of this pathogen. Note the
intermixing of health, dying, and dead
swards of grass. These are secondary
symptoms associated with root rot.
Take-all patch is sometimes
confused with chinch bug
damage
• This shot looks like chinch bugs but is
actually take all patch. A simple float using
a coffee can with both ends cut out will
readily reveal the presence of chinch bugs.
More take all patch
Gaeumannomyces graminis on a
bermudagrass putting green
• In bermudagrass the common name for this
disease if bermudagrass decline. Like St.
Augustine it is characterized by thinning
and an intermixing of healthy, dying, and
dead swards of grass. Also, as with St.
Augustinegrass, the symptoms on the
surface are secondary symptoms
associated
Courtesy Monica Elliott
with root rot.
This photo shows the intermixing
of grass in various states of
health
Bermudagrass decline is only a
problem at low heights of cut.
• This disease is peculiar to putting greens in
bermudagrass and is often worse around the
edge of the green where clean up passes
(especially triplexed) create additional wear
and compaction. This speaks to the
secondary nature of this disease. It typically
occurs on older greens with other problems
and in the hot humid weather of July and
August.
Primary root rot caused by
Gaeumannomyces graminis
• As mentioned the surface symptoms are
secondary. The primary symptom is root
rot. This photo contrast a healthy
bermudagrass root on the right (it is white
and fleshy) and a diseased root on the left
(spindley, brown, dark water soaked
lesions).
Courtesy Monica Elliott
SAD virus
• St. Augustine Decline virus
• incurable, remove and replant with resistant
cultivar
• small chlorotic spots which give leaves a
stippled appearance
• Texas east to Mississippi
Yellowing and stippling
associated with SAD virus
Slime mold
• Non-pathogenic
• produces gray, and sometimes other color,
fruiting bodies on grass leaves
• mow it off
Slime mold fruiting bodies on
grass blades
• At the fruiting stage slime mold “crawls” up
onto the grass and produces the symptoms
in this photo. It can be gray, yellow, or pink,
with gray seeming to be the most common.
• It is non-pathogenic and does not require
treatment.
Slime mold on mulch
Slime mold on mulch
Spring dead spot
• Significant problem in the transition zone
• Fairly complex combination of
– Disease (Leptosphaeria korrae, causes necrotic
ring spot in cool season grasses)
– colder than normal weather
• Usually comes back in same spots in bad
years
• soil moisture and fertility involved
Red thread
• Mild to hot weather
• looks like wilt and often exacerbated by
misdiagnosis
• broad spectrum
Red thread is easily confused
with wilt
• Closer inspection will reveal red mycellium
Red thread and a dull mower
• Multiple problems can occur on the same
turfgrass simultaneously. This picture shows
tall fescue mown with a dull rotary mower
giving it the whitish cast associated with
“mower disease” but also has a patch of red
thread developing. Dull mowers predispose
turf to numerous problems.
Vascular bundle
Close up of tall fescue
mown
ripped from the leaf
Shredding with a dull rotary mower
at the tip
• Note the tearing and shredding at the end of
the blade. A vascular bundle has been
ripped out of the leaf for a considerable
distance.
Other diseases
•
•
•
•
•
•
Spring dead spot (Ophiosphaerella spp.)
Snow mold
fusarium blight
bacterial wilts
algae (not really a disease)
moss (ditto)
Disease Models
• Methods of predicting when disease
outbreaks are likely to occur
• Typically are conservative (I.e. tend to over
predict disease outbreaks
• Good tools but should not be relied upon
exclusively for decisions on fungicide
applications
Brown patch environmental
favorability index (EFI)
• Developed in Maryland
• Uses mean relative humidity & minimum
temperature
• Scaled from 0 to 8
• value of 6 or greater fungicide application is
recommended
Mills/Rothwell dollar spot model
• Predicts outbreaks based on maximum daily
temperature & relative humidity
• Treat with fungicide if:
– maximum daily temperature exceeds 77o
F and
– relative humidity exceeds 90% and
– this combination occurs for 3 or more
days in a 7 day period
Pythium blight forcaster
• Risk is high if:
– maximum temperature exceeds 86o F and
– minimum temperature exceeds 68o F and
– relative humidity is 90% or greater for 14
or more consecutive hours
Trends in modeling
• Newer models are being
developed which consider the
length of time the foliage is wet.
• Still have a ways to go in this area
but modeling should gradually get
better as soon as we can find two
pathologist who can agree on
anything other than proper
spelling of Brown patch!
Overview of turfgrass diseases in
Florida
Common ornamental diseases
• Crown gall - Agrobacterium tumefaciens
• affects over 40 families
• gall with rounded irregular shape up to
several inches
• spread by water (is a flagellate rod)
• enters through wounds
• clean nursery stock
Crown gall
Tomato
Ligustrum
Pecan seedling
University of Georgia Plant Pathology Archive, University of Georgia, Bugwood.org
Mushroom root rot
• Clitocybe tabescens southeast US & tropics
• Armillaria mellea temperate, finer soils
• attacks almost anything anything except
monocots and ferns
• secondary wilt , mycelium between bark
and wood and honey colored mushrooms
Mushroom root rot
• remove soil in for 3’ radius and replace,
drench with bordeaux mix or ferban
• Fallow land for several years after removing
oaks
• Dig 3’ deep trenches between infected
plants and other susceptible species
• Large, important specimens may be
candidates for “surgery”
White mycellial mat between
cambium and wood
Powdery mildew
• Caused by several ascomycetes
• results in significant loss of foliage
• stunting, dwarfing, and reddening of leaves
which may occur prior to appearance of
white mycellium
• mild damp weather, mainly spring and fall
• bayleton, domain, rubigan, chipco 26019
Powdery mildew on
poinsettia
More powdery mildew
Camellia mosaic
• Viral disease of the foliage
• white to yellow spots on foliage, kind of an
“infectious varigation
• buy clean stock
• good sanitary practices
Camellia mosaic
showing
characteristic
mottling of the leaf
Coconut lethal yellowing
•
MLO which plugs vascular tissue
• lethal disease of approximately two dozen different palm
species
• yellowing of leaves followed by browning
• spread by leaf hoppers
• Susceptible species
–
–
–
–
–
Cocos nucifera (coconut palm),
Adonidia merrillii (Christmas palm),
Phoenix dactylifera (date palm)
Pritchardia spp. (loulu palms)
Caryota mitis & rumphiana (fishtail palms)
• replant with dwarf Malaysian or other resistant variety or
suppress with antibiotics
healthy palm
diseased
Coconut palms with
lethal yellowing
• Injecting palms with
oxytetracycline
suppresses the disease
but the effect is
temporary
Damping off
• Can be caused by several genera of
phycomycota and ascomycota fungi
• major killer of numerous plants in the
seedling stage
• can kill pre of post emergent
• use treated seed and treat seed bed
• Banrot, Truban, Alliette
Fire blight - Erwinia spp.
• Major bacterial disease of pear, apple,
raphiolepis, pyracantha, photinia, spirea,
and others in the rose family
• rapid blight of the apical leaves and twigs
• leaves shrivel and die, but remain attached
• prune infected branches 12” below affected
area, use good sanitation
Fire blight in apples
A blighted branch
This disease is potentially
devastating in some crops
Juniper blight
• Attacks shrubs and trees in the juniper,
cypress, and jew families
• branch tips brown progressing to base
(mites cause browning base to tip)
• moist warm weather worse on young plants
up to about 5 years old
• full sun, well drained sites, use copper spray
Phytophthora (spp.) root rot
•
•
•
•
•
•
•
•
Azaleas, camellias, pines, other ornamentals
roots rot, possibly some stem rot
secondary rapid wilt and death of shoots
warm, wet soils 68oF to 95oF, frequent rain
soil drench with Subdue or Banrot
Crown and fruit rot in apples and pears
Bud rot in palms
Damping off in seedlings
Primary and
secondary
symptoms of
Phytophthora
root rot
primary reddening of the
cambium
Secondary
decline in
the tops
Phytophthora and Thielaviopsis
Bud Rots
• Typically occurs in the rainy season
• Starts as discoloration of the youngest fronds
• No new fronds will be produced but older fronds
will remain green initially
• Fungus usually enters through an injury
• Very common on freeze damaged buds (may also
be bacterial in this instance)
• Older palms it may be too late when symptoms
appear
• Young palm may be salvagable if caught early
Phytophthora and Thielaviopsis
Bud Rots
Courtesy Monica Elliott
Phytophthora and Thielaviopsis
Bud Rots
• Phytophthora is much more common
• Cultural controls helpful
–
–
–
–
Avoid overhead irrigation
Keep foliage dry
Avoid standing water
Good sanitation practices
• Before applying fungicide get lab diagnosis
• If you are not sure apply a mixture of two
fungicides
– Preventative bud drenches for young palms in
containers when conditions indicate
Pine tree decline
• Slash pines in sandy soils, under irrigation,
and higher fertility situations
• cause not completely understood
• some success with injection of fungicide
and microelements
• eliminate irrigation and elevated fertility in
root zone of pines
Pine tree decling
• These pines, adjacent to a tee, are
receiving too much water and
fertilizer
Ganoderma zonatum
butt rot
•
•
•
•
Palms
incurable
remove soil and fumigate
plant something else
Ganoderma produces decline in
the bud and “conks” on the
trunks
Courtesy Eric Knudsen
Conks are usually honey colored
• By the time the conks appear it is too late.
Conks are usually right at the
base of the palm
Hypoxylon rot
• Usually attacks weakened
trees
• Rot of hardwoods and some
shrubs such as Camellia
• Dislodges bark and causes
thinning in crown
• Surgery on valuable
specimens, or remove plant
• Don’t confuse with lichens
Various leaf spot diseases
• Ascomycota, bacteria, a few algae
• degrades foliage, may cause loss of new
growth
• various shapes and colors of spots
• identify and use appropriate control if
necessary
Leaf spotting organisms
fungal
bacterial
algal
Tar spot on maple
Exobasidium camellias & azelias
Disease control tactics
•
•
•
•
•
•
Avoidance
exclusion
eradication
protection
host plant resistance
therapy
Some pest can be
hard to diagnose
without local
knowledge
• This is damage is
caused by deer
feeding in the winter.
Fungicide Categories
• Contact – work on leaf & stem surface to
prevent penetration by fungus
• Systemic – are absorbed into plant tissue
and are translocated (primarily in xylem)
• Local systemic – absorbed but only move a
short distance, don’t move in vascular tissue
• Mesostemic – new category strongly
attracted to plant surface and are absorbed
by waxy layers
Comparison of fungicide categories
Contact
• Protective
• Not translocated
• New growth is not
protected
• Typically for foliar
diseases only
• Broad spectrum
• Little possibility of
resistance developing
• Typically not used for
root pathogens
Systemic
• Protective & curative
• Translocated
• New growth is
protected
• For foliar and root
diseases
• Specific mode of action
• More possibility of
resistance developing
• Effective on root
pathogens
Contact fungicide families
• Family
• Examples
• (Common names)
•
•
•
•
•
•
•
•
•
•
Aromatic hydrocarbons
Dithiocarbamates
Benzonitrile
Phthalimides
Triazines
Chloroneb, ethazol, PCNB
Thiram, mancozeb, maneb
Chlorothalonil
Captan
anilazine
Systemic fungicide families
• Family
• Examples
• (Common names)
• ergosterol biosysthesis
inhibitors (EBI’s) also
known as (DMI’s)
• Benzimidazoles
• Acetanilide
• Phosphonates
• Fenarimol, cyproconazol,
triadimefon, propiconazol,
tebuconazol, myclobutanil
• Benomyl, thiophanate-methyl
• Metalaxyl
• Fosetyl-Al
Local-Systemic fungicide families
• Family
• Dicarboximides
• Benzamide
• carbamates
•
•
•
•
•
Examples
(Common names)
Iprodione, vinclozolin
Flutolanil
propamocarb
Mesostemic fungicides
• Family
• strobilurin
• Examples
• (Common names)
• Azoxystrobin, trifloxystrobin