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 Introduction
 Adaptation
 Management
 Summary






Group Title: Florida Cooperative Extension Service circular 881
Title: Bentgrass in Florida
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00049227/00001
 Material Information
Title: Bentgrass in Florida some important considerations
Series Title: Circular
Physical Description: 4 p. : ill. ; 28 cm.
Language: English
Creator: McCarty, L. B ( Lambert Blanchard ), 1958-
Publisher: Florida Cooperative Extension Service
Place of Publication: Gainesville
Publication Date: 1990
 Subjects
Subject: Turfgrasses -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: L.B. McCarty ... et al..
General Note: Cover title.
General Note: "June 1990."
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00049227
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 22441483

Table of Contents
    Copyright
        Copyright
    Introduction
        Page 1
    Adaptation
        Page 1
    Management
        Page 2
        Page 3
    Summary
        Page 4
Full Text





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




3e
3 C.._June 1990


Bentgrass in Florida


Circular 881
Library


Some Important Considerations
i; i'".P- of Fiorida


L. B. McCarty, J. L. Cisar, A. E. Dudeck, T.

Introduction
Creeping bentgrass (Agrostis palustris Huds.)
forms a fine textured turf with superior shoot
density, uniformity, and turfgrass quality when
properly managed in cool, humid climates.
Cultivars of creeping bentgrass most widely used
for putting greens in the United States include
Penncross, Penneagle, Pennlinks, Seaside,
Emerald, and Cohansey (C-7). All were developed
in the cooler regions of the northern United States
as a result of selection and breeding programs
using germplasm of bentgrasses introduced from
Europe. Questions are often asked about the
range of adaptation of bentgrass into warm, humid
regions. The purpose of this bulletin is to provide
some information to those who are considering
growing bentgrass in Florida.

Adaptation
Distribution and adaptive potential of
turfgrasses are largely governed by their innate
characteristics and by the climate of a given region.
Cool season turfgrasses such as bluegrass (Poa
spp.), fescue (Festuca spp.), ryegrass (Lolium spp.),
and bentgrass originated in the cooler temperate
regions of the world. They are adapted to this
climate and can persist as introduced species in
other regions with similar climate. Warm-season
turfgrasses such as bermudagrass (Cynodon spp.),
zoysia (Zoysia spp.), and St. Augustinegrass
(Stenotaphrum secundatum) originated in the
warmer climatic zones of the world and have
evolved mechanisms that allow for longterm
persistence in warmer regions. In specialized
situations, grasses can be and are successfully
utilized outside their climatological zone of
adaptation; for example, the winter overseeding
of bentgrass and ryegrass on golf courses in the
South or their year-round use in the transition
zone. Growing grasses beyond their climatic zones
is not an indication of wider adaptation. It reflects


*Assistant professors and professor of Environmental
Horticulture, professor and associate professor of Plant Pathology,
and professor of Nematology, IFAS, University of Florida.


E. Freeman, G. W. Simone, and R.A. Duiiin

the ability of turfgrass managers to recognize
agronomic opportunities to temporarily use
turfgrasses outside their zone of adaptation for
specialty purposes during periods of favorable
weather.
Favorable conditions exist for bentgrass growth
when air temperatures are between 600 and 750F.
Root growth optimum soil temperature is 500 to
650F. In many parts of Florida, these conditions
exist for limited periods. Successful use of
bentgrass can be achieved only for certain portions
of the year. Once these optimums are exceeded, in
conjunction with higher relative humidity,
bentgrass survival is diminished. Climatological
conditions are probable that favor continued warm-
season grass growth and poor cool-season grass
germination, causing failures of fall overseedings.
Turfgrass managers, like other professional
managers of agronomic commodities, understand
the vagaries of weather and the risks of trying to
extend the season or use of a specific crop.
Research has demonstrated that the upper
limiting soil temperature range for bentgrass is
between 800 and 950F. In this range, bentgrass
growth declines, and the ability of the plant to
recuperate from traffic or disease, insect or weed
pressure, is dramatically reduced. Direct high
temperature kill due to plant membrane
dysfunction can be induced when soil temperatures
reach 1000 to 1100F. While direct-kill soil
temperatures are rarely achieved or maintained
for long periods of time, soil temperatures above
optimal for bentgrass growth are the norm in
Florida for extended time periods. Under these
conditions, bentgrass does not efficiently produce
carbohydrates by photosynthesis. Reserve
carbohydrates are depleted and root growth
eventually declines. The decreased root surface
area limits the effective zone for nutrient and
water uptake.
Bermudagrass, on the other hand, increases
carbohydrate manufacturing (photosynthesis)
with increasing temperature and light intensity
and has lower rates of respiration at high air and
soil temperatures. Warm season plants, such as
bermudagrass, produce carbohydrates more
efficiently and use less water compared to cool




3e
3 C.._June 1990


Bentgrass in Florida


Circular 881
Library


Some Important Considerations
i; i'".P- of Fiorida


L. B. McCarty, J. L. Cisar, A. E. Dudeck, T.

Introduction
Creeping bentgrass (Agrostis palustris Huds.)
forms a fine textured turf with superior shoot
density, uniformity, and turfgrass quality when
properly managed in cool, humid climates.
Cultivars of creeping bentgrass most widely used
for putting greens in the United States include
Penncross, Penneagle, Pennlinks, Seaside,
Emerald, and Cohansey (C-7). All were developed
in the cooler regions of the northern United States
as a result of selection and breeding programs
using germplasm of bentgrasses introduced from
Europe. Questions are often asked about the
range of adaptation of bentgrass into warm, humid
regions. The purpose of this bulletin is to provide
some information to those who are considering
growing bentgrass in Florida.

Adaptation
Distribution and adaptive potential of
turfgrasses are largely governed by their innate
characteristics and by the climate of a given region.
Cool season turfgrasses such as bluegrass (Poa
spp.), fescue (Festuca spp.), ryegrass (Lolium spp.),
and bentgrass originated in the cooler temperate
regions of the world. They are adapted to this
climate and can persist as introduced species in
other regions with similar climate. Warm-season
turfgrasses such as bermudagrass (Cynodon spp.),
zoysia (Zoysia spp.), and St. Augustinegrass
(Stenotaphrum secundatum) originated in the
warmer climatic zones of the world and have
evolved mechanisms that allow for longterm
persistence in warmer regions. In specialized
situations, grasses can be and are successfully
utilized outside their climatological zone of
adaptation; for example, the winter overseeding
of bentgrass and ryegrass on golf courses in the
South or their year-round use in the transition
zone. Growing grasses beyond their climatic zones
is not an indication of wider adaptation. It reflects


*Assistant professors and professor of Environmental
Horticulture, professor and associate professor of Plant Pathology,
and professor of Nematology, IFAS, University of Florida.


E. Freeman, G. W. Simone, and R.A. Duiiin

the ability of turfgrass managers to recognize
agronomic opportunities to temporarily use
turfgrasses outside their zone of adaptation for
specialty purposes during periods of favorable
weather.
Favorable conditions exist for bentgrass growth
when air temperatures are between 600 and 750F.
Root growth optimum soil temperature is 500 to
650F. In many parts of Florida, these conditions
exist for limited periods. Successful use of
bentgrass can be achieved only for certain portions
of the year. Once these optimums are exceeded, in
conjunction with higher relative humidity,
bentgrass survival is diminished. Climatological
conditions are probable that favor continued warm-
season grass growth and poor cool-season grass
germination, causing failures of fall overseedings.
Turfgrass managers, like other professional
managers of agronomic commodities, understand
the vagaries of weather and the risks of trying to
extend the season or use of a specific crop.
Research has demonstrated that the upper
limiting soil temperature range for bentgrass is
between 800 and 950F. In this range, bentgrass
growth declines, and the ability of the plant to
recuperate from traffic or disease, insect or weed
pressure, is dramatically reduced. Direct high
temperature kill due to plant membrane
dysfunction can be induced when soil temperatures
reach 1000 to 1100F. While direct-kill soil
temperatures are rarely achieved or maintained
for long periods of time, soil temperatures above
optimal for bentgrass growth are the norm in
Florida for extended time periods. Under these
conditions, bentgrass does not efficiently produce
carbohydrates by photosynthesis. Reserve
carbohydrates are depleted and root growth
eventually declines. The decreased root surface
area limits the effective zone for nutrient and
water uptake.
Bermudagrass, on the other hand, increases
carbohydrate manufacturing (photosynthesis)
with increasing temperature and light intensity
and has lower rates of respiration at high air and
soil temperatures. Warm season plants, such as
bermudagrass, produce carbohydrates more
efficiently and use less water compared to cool








season plants. In contrast, bermudagrass does
not grow effectively when temperatures are cool
(<700F), due to its high temperature requirement
for efficient photosynthesis.

Management
Water Management
Water management is probably the most
important key to quality bentgrass production.
This begins with exact water control in the form of
supplemental irrigation and internal and external
soil drainage. The United States Golf Association,
Green Section, recommends a rate of 4 to 6 inches
per hour as ideal in terms of internal soil water
transmission for growing bentgrass. Many existing
greens do not meet this range of internal drainage.


Fig. 1. Algal layer that often forms during periods of frequent
irrigation on poorly drained soil.

Therefore, partial or complete green soil
modification may be necessary prior to bentgrass
establishment. Problems with reduced soil oxygen
(wet wilt) and disease development occur with
less than minimum drainage requirements.
Meanwhile, exact control of water application
is absolute. Because bentgrass forms fewer roots
during the summer, wilting quickly occurs,
requiring hand watering to each putting green
several times daily. Supplemental watering by
syringing may be necessary to reduce canopy
temperature. Overwatering inadequately drained
greens may result in wet wilt and often results in
the formation of algae (scum) layers under such
high water-use conditions (Fig. 1). The naturally
high pH irrigation water found in many portions
of Florida may also limit micronutrient availability.
Most portions of Florida have also been placed
under restricted water use by the various regional


Water Management Districts. Under various
mandatory restrictions, golf courses can be watered
only a certain number of times per week and only
during cooler portions of the day (e.g. mornings).
The additional mid-day syringing required to
maintain bentgrass during the summer might not
be readily available during future water shortages.
Mowing
To obtain a desired playing surface, bentgrass
generally requires daily mowing. To reduce soil
compaction and shearing with triplex mowers,
especially from the clean-up pass, bentgrass should
be hand-mowed throughout the summer months.
Raising the height of cut to a minimum of 1/4 inch
during summer should help prevent these
problems.
Fertilization
Nitrogen fertility management, like water, plays
a significant role in controlling periods of lush
growth, disease susceptibility, and year-round
color. Good bentgrass growth requires an annual
rate of 4 to 8 lbs of actual nitrogen per 1000 ft2, and
it should be applied in a slow-release form. Nearly
all of this is applied in the fall and winter months;
only about 10% is applied in the summer. Excessive
summer nitrogen fertilization promotes shoot
growth at the expense of root growth. It also
increases bentgrass susceptibility to diseases,
especially brown patch and Pythium. As a result
of low summer fertility and high temperatures,
putting greens lose their dark-green color and
recuperative potential from ball-marks and
machine and spike damage. Consequently,
supplemental iron is frequently applied to promote
color.


Fig. 2. Pythium root rot and Rhizoctonia brown patch of
poorly managed bentgrass in summer.








Due to the high sand content of most Florida
greens and excessive moisture application
required, potassium levels tend to remain low on
most bentgrass greens. Adequate potassium and
phosphorus soil levels are essential for root growth
and stress tolerance to environmental extremes.
Bentgrass grows best at a soil pH between 5.5 and
6.5.

Weed control
Due to the high potential for soil compaction
from management practices, excessive traffic
damage and summer-season thinning, bentgrass
greens typically become invaded with annual
weeds such as goosegrass, crabgrass, and Poa
annua. Only pre-emergence grass herbicides are
effective on bentgrass without serious damage.
Postemergence grass herbicides are not available
or have little margin of error on the applicator's


Fig. 3. Bentgrass's relatively poor tolerance to most
postemergence grass herbicides.

part (Fig. 2). Typically, hand removal is the only
method of postemergence grass weed control once
bentgrass is established. Broadleaf herbicides
can generally be used on bentgrass. However, an
application rate of only one-half strength is
recommended, and this should be applied only
when temperatures are less than 800F. Excessive
phytotoxicity may result if these precautions are
not followed.
Diseases and Nematodes
The first line of defense against disease is an
actively-growing, healthy plant. Bentgrass, when
grown outside its natural adaptation range in the
cool, humid northeast and northwest United
States, is weakened by excessive summer
temperatures, and becomes more disease
susceptible. Fungi disease commonly associated


with bentgrass in the southern states includes: a)
dollar spot, b) brown patch, c) Helminthosporium,
d) Southern blight (Sclerotium spp.), e) fairy rings,
and f) Pythium spp (Fig. 3). Other problems with
bentgrass include nematodes and the 'black layer.'
Fungicides are usually required every 7 to 10
days to help combat diseases. Northern
researchers recommend 12 nonsystemic, 2
systemic, and 7 Pythium-specific fungicidal
applications annually for bentgrass grown in the
South. Only one or possibly two fungicides
specifically for root-rot Pythium species are
available, and the disease is thought to be rapidly
developing resistance to these root-rot specific
fungicides. Bermudagrass, on the other hand, is
normally susceptible only to dollarspot and
Helminthosporium leafspot. These two diseases
are suppressed by proper fertilization and do not
normally require fungicide applications.
Nematodes are also a perennial problem for
most turf growers in Florida. Nematodes can
quickly build to damaging levels in Florida's semi-
tropical climate and sandy soils. Populations
peak at those temperatures which result in
bentgrass root decline (850F), thus contributing
further to root loss. Using certain nematicides
such as ethoprop (Mocap) may result in excessive
phytotoxicity to treated bentgrass.
Insects
Insect problems on bentgrass are usually in
flushes and easily controlled if treated before
extensive damage occurs. Troublesome insects in
bentgrass in the south include cutworms, sod
webworms, and armyworms. Florida's heavy mole
cricket population could also be a serious problem
on bentgrass.

Additional Concerns
Penncross segregation Certified Penncross
bentgrass is a polysynthetic variety from 3 parent
strains to give 9 possible crosses. Only the first
generation of seed is certified. Uncertified
Penncross from second generation or more seed
sources will segregate into distinct mottled patches
given a false appearance of disease occurrence or
contamination, and may result in surface grain.
Member education should be attempted to prevent
misdiagnosis and excessive concern.
Wind movement To reduce the heat load on
bentgrass in the summer, all low-growing tree
limbs, shrubs, and bushes surrounding the putting
greens should be cleared to allow adequate air
circulation. Failure to do so creates pockets of hot,
humid air which disperse heat poorly, thus adding























Fig. 4. Severe localized dry spots that often develop when
golf greens are irrigated frequently but lightly.

further strain on bentgrass survival. Some golf
facilities may have to resort to such extremes as
placing fans on their greens to promote air
circulation to prevent heat buildup.
Soil compaction Bentgrass greens typically
become severely compacted by heavy traffic and
excessive watering. This growth condition also is
conducive to other problems such as surface algae
build-up, the black-layer phenomena, and weed
incidence. Periodic deep-tine or drill-type
aerification is often required to help alleviate
these problems. Specialized equipment to perform
these is difficult to obtain and is expensive.
Due to the use of high sand contents for internal
green "drainage, localized dry spots often develop
in summer (Fig. 4). These dry spots are
troublesome to re-wet without potentially soaking
normal areas. Frequent aerification, hand
syringing, and the use of wetting agents help
reduce the incidence of dry spots.
Yearly reseeding Due to summer thinning of
bentgrass, fall reseeding probably would be
required in most areas of Florida. Seed supply
and costs are often unpredictable; seed is hard to
obtain, and may be very expensive. Establishment
of a good rapport with a reputable seed dealer is


recommended to help ensure an adequate supply
of good quality seed.
Bermudagrass encroachment During summer
months, bermudagrass commonly encroaches into
bentgrass greens, disrupting playing surfaces and
color uniformity. Presently, there are no selective
herbicides to correct this problem. Either spot
spraying with a non-selective herbicide or hand
removal are the only effective options.
Traffic control Realistic growth of bentgrass in
Florida during the summer will probably require
some form of traffic control. Afternoon play may
be suspended if temperatures exceed 850 to 900F
or if greens remain in a wilted state. Ball mark
and spike damage will repair themselves slowly,
at best, and cups should be changed daily to
distribute traffic during the summer. Adequate
water quantity and quality must be ensured,
especially during the stressful heat periods. This
may require back-up pumps and digging a reliable
well.

Summary
In summary, bentgrass grown in Florida should
be considered only as a temporary turf suitable for
winter overseeding play. Management practices
to help reduce. heat buildup through enhanced
evaporation include supplemental water irrigation
by syringing and increased air movement by
removing low growing shrubs and trees. Practices
to promote healthy bentgrass include adequate
soil nutrient levels, avoiding excess nitrogen
application, and applying supplemental iron for
summer color. Traffic control, proper surface with
excellent internal soil water drainage, high mowing
height, along with constant disease and insect
recognition and control are required. Unless new
bentgrass cultivars can be developed which are
comparable in water requirements and pest
resistance to bermudagrass, the University of
Florida does not recommend the use of bentgrass
as a year-round putting surface in this state.


This publication was produced at a cost of $1,429.90, or 68 cents per copy, to inform golf course
managers on scientific and practical strengths and limitations of growing bentgrass in Florida. 7-2.1-90


COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, John T. Woeste,
Director, in cooperation with the United States Department of Agriculture, publishes this information to further the purpose of the May 8 and June
30,1914 Acts of Congress; and is authorized to provide research, education information and other services only to individuals and institutions that
function without regard to race, color, sex, age, handicap or national origin. 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 .......i....
is available from C. M. Hinton, Publications Distrubution Center, IFAS Building 664, University of Florida, Gainesville, Florida 32611. Before
publicizing this publication, editors should contact this address to determine availability.




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