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Group Title: Circular - University of Florida. Florida Cooperative Extension Service ; 221-G
Title: Turfgrass diseases and their control
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Permanent Link: http://ufdc.ufl.edu/UF00072519/00001
 Material Information
Title: Turfgrass diseases and their control
Series Title: Circular Florida Cooperative Extension Service
Physical Description: 11 p. : col. ill. ; 23 cm.
Language: English
Creator: Atilano, Raymond Anthony
Freeman, T. E ( Thomas Edward ), 1930-
Simone, Gary W ( Gary Wayne ), 1950-
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1982?
 Subjects
Subject: Turfgrasses -- Diseases and pests -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: R.A. Atilano, T.E. Freeman, and G.W. Simone.
Funding: Circular (Florida Cooperative Extension Service) ;
 Record Information
Bibliographic ID: UF00072519
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 10736733

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HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





/May 1982


TURFGRASS DISEASES

And Their Control
R.A. Atilano, T.E. Freeman, and G.W. Simone
AGRICULTURAL LIBRARY
JAN 0 7 1983

Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
John T. Woeste, Dean for Extension


Circular 221-G















































On the cover: Brown patch in St. Augustinegrass with regrowth in the center
area.











TURFGRASS DISEASES
AND THEIR CONTROL
R. A. Atilano, T. E. Freeman, and
G. W. Simone





















R. A. Atilano is an Assistant Professor and Turf and Ornamental Disease Special-
ist at the Ft. Lauderdale Agricultural Research and Education Center. T. E. Free-
man is a Professor of Plant Pathology and Turfgrass Disease Specialist at Gaines-
ville. G. W. Simone is an Assistant Professor and Extension Plant Pathologist at
Gainesville.









TURFGRASS DISEASES AND
THEIR CONTROL
R. A. Atilano, T. E. Freeman, and G. W. Simone

Diseases of turfgrass frequently disfigure plantings around homes,
recreational areas, and commercial grounds. Pathogens (organisms
that cause diseases) are commonly present in turfgrass plantings,
and the climate in Florida frequently favors disease development.
Fortunately, grasses receiving proper cultural practices (irrigation,
mowing, fertilizer, and others) are not likely to be as badly damaged
as are grasses not receiving proper care. Cost and energy savings
result from use of good cultural practices that enhance plant vigor
and increase tolerance to disease. The need for costly pesticide ap-
plications is thereby reduced.

CULTURAL CONTROL
Turfgrass managers, including homeowners, should learn the
cultural requirements of the grass species and cultivar which they
are maintaining. For example, the mowing height and mowing fre-
quency for best health varies with each turfgrass species and-culti-
var. Improper mowing height and frequency can weaken the grass
and lower its tolerance to disease. Dull mower blades inflict greater
tissue damage than sharp blades. The damage is first evident as
unsightly white to brown discoloration of the turf 1 to 2 days follow-
ing mowing. The damaged tissue provides an avenue through which
pathogens may infect the grass.
Diseases of turfgrasses are favored by prolonged periods of high
humidity, rain, fog, or heavy dew because moisture on the plant
surface is necessary for most pathogens to infect turfgrasses. Turf-
grass that enters the night period moist from irrigation is more
inclined to become diseased. Little can be done to modify natural
moisture conditions; however, irrigation can be controlled to reduce
disease incidence by promoting leaf drying. Irrigating early in the
morning allows the grass to dry before evening.
The susceptibility of turfgrasses to disease is also affected by nutri-
tion. Properly fertilized grass is more resistant to disease and recov-
ers faster if it should become diseased. In general, moderate fertiliza-
tion and use of slow release fertilizers should be practiced. However,
turf managers should remember that each grass species and cultivar
may have unique fertility or other cultural requirements that should
be provided for healthy growth.









CHEMICAL CONTROL


Chemical control of turfgrass diseases can be achieved by proper
use of fungicides. A uniform application over the entire planting is
usually necessary and will be most effective if done early in disease
development. Most fungicides are effective for a relatively short time,
often not more than 14 days. Sunlight, rain, irrigation water, and
mowing affect the rate at which the protective chemical is broken
down and removed from the plant. Repeat applications are often
necessary to control a disease during periods when weather condi-
tions favor disease. Avoid irrigating or mowing immediately after
application of fungicides.
Fungicides should always be used in accordance with the manufac-
turer's instructions on the product label. Information on the label
includes the diseases for which the fungicide is effective, proper rates,
cautions with respect to mixing with other chemicals, frequency of
application, and safety precautions. Some of the fungicides are effec-
tive only for control of specific diseases so it is important to obtain an
accurate diagnosis in order to select an appropriate fungicide.






















Fig.1. St. Augustinegrass with Fig. 2 Cercosporaleaf spotsymp-
symptoms of brown patch toms on St. Augustinegrass.
disease.
































Fig. 3. Dollar spot disease on ber- Fig. 4. Bermudagrass leaves show-
mudagrass. ing typical symptoms caused
by the dollar spot disease.


Fig. 5 Fairy ring symptoms with mushrooms in bermudagrass.











KEY FOR IDENTIFICATION OF TURF DISEASES
I. Grass affected in distinct patches.
A. Affected areas 2 to 3 inches in diameter.
Leaf spot-type lesions present ................ Dollar spot
B. Affected area usually larger than 2 to 3 inches in diameter.
Leaf spot-type lesions not present.
1. Ring or arc of lush growth or occasionally dead
grass; mushrooms may be present ......... Fairy ring
2. Patches not associated with ring of lush growth.
a. Affected areas tend to be in streaks. Grass blades
matted together. Primarily on ryegrass and
bermudagrass .................... Pythium blight
b. Affected area circular; often with wilted "smoke ring"
margin. Grass blades not matted ..... Brown patch
II. Grass not affected in distinct patches.
A. Orange pustules present on leaf blades ............. Rust
B. Orange pustules not present on leaf blades.
1. Leaf spots present.
a. Primarily on
ryegrass and bermudagrass..... Helminthosporium
leaf spot
b. Primarily on St. Augustinegrass.
i. Leaf spots oval to irregular with brown borders
and tan to gray centers ........ Gray leaf spot
ii. Leaf spots linear with purple borders and
tan to white centers ...... Cercospora leaf spot
2. Leaf spots not present.
a. Grass covered with an easily removed crusty and/or
sooty growth ........................Slime mold
b. Chlorosis or mottling of leaves associated with gen-
eral decline.
i. All grasses .............. Root rot, Nematodes*
ii. St. Augustinegrass ...... St. Augustine Decline
Virus (SAD)**

*Request nematode information from County Extension Office.
**Not yet recorded from Florida, but may occur in the future.































Fig. 6 Gray leaf spot of St. Augus-
tinegrass. Note fresh, dark
spots in the top, right leaf
and older spots with tan cen-
ters in other leaves.


3. 7. Helminthosporium leaf spot
in bermudagrass.


Fig. a. Pytnium root rot in Dermudagrass.































Fig. 9. Cottony blight disease of ryegrass caused by Pythium.


Fig. 10. Rust disease on ryegrass with masses of rust pustules on the
leaves that are typical of disease symptoms on other grasses.































a lme moia Is noi a disease, ouI is commonly ooserveu on leai
surfaces of Florida turfgrasses.


Fig. 12. Symptoms of St. Augustine decline disease. This has not
occurred in Florida to date.






TURFGRASS DISEASES THAT OCCUR COMMONLY IN FLORIDA

Disease Grasses Cultural Effective
& Organisms Affected Nature of Disease Control Fungicides*
Brown patch Bahia, bermuda, Grasses killed in more or less circular patches Fertilize mod- Acti-dione Thiram
(Rhizoctonia carpet, that begin as small spots and may expand to erately. Avoid Chipco 26019
solani) centipede, rye, several feet in diameter. Margin of patches may applying excess Daconil 2787
St. Augustine, appear wilted. Regrowth in center of patch may nitrogen. Irri- Duosan
zoysia give "doughnut-like" appearance. Thinning of gate in the early Fore
turf over a large area can occur and a root rot morning. Fungo
may be evident. Usually occurs during warm, Syringe, pole, or Terraclor
humid weather and is encouraged by excess ni- brush off dew. Tersan 75
trogen fertilizer. St. Augustine, carpet, cen- Remove clip- Tersan LSR
tipede, and rye grasses are more severely pings. Avoid Tersan 1991
affected. thatch buildup.
Cercospora leaf St. Augustine Brown to purple leaf spots that may develop a Disease severity None available
spot tan center with age. Leaves will yellow, wither, is reduced by ap-
(Cercospora and die when the disease is severe. Areas of plication of ni-
fusimaculans) turf will appear to thin or "melt out." trogen-contain-
ing fertilizer.
Irrigate in early
morning. Bitter
blue-type selec-
tions are more
resistant.
Dollar spot Bahia, bermuda, Fine textured grasses killed in distinct patches Disease severity Acti-dione Thiram
(Sclerotinia centipede, St. 2 to 3 inches in diameter. Patches may be is reduced by ap- Chipco 26019
homoeocarpa) Augustine, larger in coarser grasses. Patches may coalesce plication of ni- Daconil 2787
zoysia to form large diseased areas. Grass blades in trogen-contain- Duosan
margin of patches develop tan leaf spots with ing fertilizer. Fungo
reddish-brown borders. Occurs during mild to Irrigate in early Tersan 1991
warm humid weather. White, web-like strands morning. Avoid
of the fungus may be visible. Bermuda, bahia, thatch buildup.
and zoysia grasses are more severely affected.







TURFGRASS DISEASES THAT OCCUR COMMONLY IN FLORIDA (continued)
Disease Grasses Cultural Effective
& Organisms Affected Nature of Disease Control Fungicides*



Fairy ring All grasses Three types occur in semi-circular to circular Difficult to con- Soil fumigation
(Chlorophyllum sp., bands in which mushrooms of the fungus are trol. Declining with methyl bro-
Marasmius sp. frequently produced. Type I, grass is killed, areas often re- mide-chloropicrin
and others) Type II, grass is only stimulated. Type III, spond to addi-
grass is unaffected. Rings persist and increase tional water and
in size for several years. Types II and III are fertilizer. Addi-
the most common in Florida. tional fertilizer
will mask stimu-
lated Type II
rings.
Gray leaf spot Bermuda, rye, Round to oblong leaf spots that are brown to More frequently Acti-diome Thiram
(Pyricularia grisea) St. Augustine ash-colored with purple to brown margins, a problem on re- Daconil 2787
Spots may be covered with a gray mold in cently planted
warm, humid weather. Lesions may also occur St. Augustine
on the stems. In severe cases leaves have a grass than on
scorched appearance. Prevalent during the established
rainy summer months. Primarily a disease of lawns. Certain
St. Augustinegrass. herbicides, ex-
cess nitrogen
fertilizer, and
heavy traffic in-
crease severity.








TURFGRASS DISEASES THAT OCCUR COMMONLY IN FLORIDA (continued)
Disease Grasses Cultural Effective
& Organisms Affected Nature of Disease Control Fungicides*
Helmintho- Bermuda, rye, Small oblong purplish to brown leaf spots. Spots Maintain an Acti-dione Thiram
sporium leaf spot St. Augustine, may have a tan center. Heavily infected leaves even moisture Chipco 26019
(Helmintho- zoysia wither and die. An overall thinning or "melting level. Irrigate in Daconil 2787
sporium spp.) out" results. May occur at any time of the year early morning. Duosan
when grass is growing. Sheath and crown rot Raise mowing Fore
may be evident. Bermuda and rye grasses are height to reduce Tersan LSR
more severely affected. disease severity
during disease
outbreak.
Pythium blight Bermuda, rye Grass rapidly dies in spots or streaks. In the Improve aera- Banol
(Pythium apha- early stage the affected grass is blackened and tion and drain- Koban
nidermatum) has a greasy appearance. At times the affected age conditions. Subdue 2E
spots may have a "cottony" appearance due to Avoid frequent, Terrazole
abundant growth of the fungus. Occurs during shallow irriga- Tersan SP
warm, humid weather in poorly drained soil. tions. Reduce
mowings and
minimize equip-
ment or foot
traffic across wet
infected turf.
Rust Bermuda, rye, Small yellow to orange or reddish brown pus- Remove clip- Acti-dione Thiram
(Puccinia spp.) St. Augustine, tules on the leaves. Heavily infested turf has an pings. Maintain Daconil 2787
zoysia overall unthrifty appearance. Prevalent during rapid growth. Dithane Z-78
mild to warm humid weather. Fore
Tersan LSR








TURFGRASS DISEASES THAT OCCUR COMMONLY IN FLORIDA (continued)
Disease Grasses Cultural Effective
& Organisms Affected Nature of Disease Control Fungicides*



Root rots All grasses Each of the organisms mentioned can cause in- Avoid over- Correct diagnosis
(Pythium, water jury to roots. Nematodes do well in sandy soils, watering. Aerate very important for
molds, The root rotting fungi are encouraged by soils compacted and selecting an appro-
nematodes) that are poorly drained or are kept wet for long poorly drained private chemical.
periods. Nematodes and root rotting fungi may soils. Seek aid from a di-
occur together in turfgrass roots. Roots are agnostic laboratory.
dark, soft, with few or no feeder roots present.
Slime mold All grasses Grass covered with a gray to black soot-like Brush or wash Not needed.
(Primarily growth or prominent white or yellow masses, the mold off the
Physarum sp. Occurs during warm humid weather. Slime grass. Mowing
and Fuligo sp.) molds do not injure turf. will eliminate
the condition.
St. Augustine St. Augustine Chlorotic mottle, stunting. The severe strain of Avoid planting None
Decline (SAD). the virus causes death. The disease has not yet infected sod. Use
(Virus, SADV) been detected in Florida. resistant
varieties of
grass.
*Trade names are used with the understanding that no endorsement is intended nor is criticism implied of similar products which are not men-
tioned. All chemicals should be used in accordance with the manufacturer's instructions.





















































This publication was promulgated at a cost of $2,291.80 or .39
cents per copy to present information on controlling diseases
of turfgrass. 9-6M-82




COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORI-
DA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, K. R.
Tefertlller, director, In cooperation with the United States Department IFA l
of Agriculture, publishes this Information to further the purpose of the
May 8 and June 30, 1914 Acts of Congress; and Is authorized to pro-
vide research, educational Information and other services only to Indi-
viduals and Institutions that function without regard to race, color, sex or national ori-
gin. Single copies of Extension publications (excluding 4-H and Youth publications) are
available free to Florida residents from County Extension Offices. Information on bulk
rates or copies for out-of-state purchasers Is available from C. M. Hinton, Publications
Distribution Center, IFAS Building 664, University of Florida, Gainesvllle, Florida
32611. Before publicizing this publication, editors should contact this address to deter-
mine availability.




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