• TABLE OF CONTENTS
HIDE
 Front Cover
 Weed control
 Types of herbicides
 Weed control in Centipedegrass
 Weed control in St. Augustineg...
 Precautions of herbicide appli...
 Important
 Back Cover






Group Title: Circular - Florida Cooperative Extension Service - 576
Title: Weed control in centipedegrass and St. Augustinegrass
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00028005/00001
 Material Information
Title: Weed control in centipedegrass and St. Augustinegrass
Series Title: Circular Florida Cooperative Extension Service
Physical Description: 12 p. : ; 23 cm.
Language: English
Creator: Peacock, Charles Harris, 1946-
Currey, Wayne Lee
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1983?
 Subjects
Subject: Weeds -- Control   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: Charles H. Peacock and Wayne L. Currey.
General Note: Cover title.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00028005
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 - 10736706

Table of Contents
    Front Cover
        Cover
    Weed control
        Page 1
    Types of herbicides
        Page 2
    Weed control in Centipedegrass
        Page 3
    Weed control in St. Augustinegrass
        Page 4
    Precautions of herbicide applications
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
    Important
        Page 12
    Back Cover
        Cover
Full Text
(ir
y~~G


Weed Control in Centipedegrass
and St. Augustinegrass

Charles H. Peacock and Wayne L. Currey


Cilar 576
Cir ular 576


Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences
University of Florida / J. T. Woeste, Dean








Weed Control in Centipedegrass
and St. Augustinegrass

Charles H. Peacock and Wayne L. Currey*


Weeds are a common and important problem in warm-season turfgrasses.
Weed control in centipedegrass and St. Augustinegrass presents special
problems compared with other warm-season grasses, since these species
have limited tolerance to 2,4-D and related compounds or arsonates (MSMA,
DSMA) which are usually used to control troublesome weeds such as
pennywort, spurges, and goosegrass.
Weeds appear in the lawn area where the grass is thin or weak and are sel-
dom a problem in healthy turf. Weeds do not kill out healthy grass. The turf-
grass species and cultivars being used today were selected because of their
aggressive and highly competitive nature, thus allowing them to compete
with weeds.
Most commonly, weeds appear due to improper management of a turf
area. Improper cultural practices including mowing too closely and infre-
quently, not following suggested fertilization rates, and improper irrigation
practices are the primary causes for a reduction in turf quality. In addition,
inadequate control of insects, diseases, and nematodes will also damage the
turf and permit weed invasion.
Herbicides may temporarily remove the weeds; however, unless the basic
cause of the weakened turf stand is corrected, weeds will continue to be a
major problem. Weed control will only be successful if appropriate main-
tenance is used to keep the grass in a good, healthy, growing condition.

Weed Control

There are four primary methods of controlling weeds.
Cultural Practices Good quality turf demands attention to the three pri-
mary cultural practices. Proper mowing, fertilization, and irrigation will
maintain the turf in a healthy vigorous condition (see OH-9, OH-10, OH-20,
and SL-21). An aggressive turf will compete with most weed species so the
first method of weed control should be a sound management system for turf-
grass growth. Auxiliary cultural practices are also important. Keep thatch
to a minimum by periodic dethatching. Apply pest control measures to pre-
vent the turf from being injured and thinned thus allowing for weed invasion.
Mechanical- Pulling weeds out by hand is an effective method for removing
annual weeds. However, it is labor consuming and practically a constant job,

*Assistant Professor Extension Turfgrass Specialist, Ornamental Horticulture Depart-
ment; and Associate Professor -Weed Scientist, Agronomy Department; IFAS, Univer-
sity of Florida, Gainesville.







and tenacious perennial weeds are a major problem. Depending on resources
it can be an expensive or cheap, but effective method of weed control.

Mowing Many weeds will not tolerate mowing. Following recommended
mowing practices of correct cutting height and frequency will minimize
weed problems. Additionally, many annual weeds will be eliminated through
repeated removal of the seedhead before it matures and sheds seed.
Herbicides Herbicides are an effective method of controlling problem
weeds. However, control is achieved only if the proper material is accurately
applied at the correct time and rate. Check product labels concerning these
factors of application.

Types of Herbicides

Preemergence These herbicides require application before germination of
the weed seed. A preemergence herbicide provides several weeks of residual
control in the soil and will kill the seedling weeds as they emerge. The dis-
advantage to the use of this type of herbicide is the difficulty of properly tim-
ing applications to coincide with various germination times of weed species.
If applied too late in the growing season, the target weed will have germi-
nated and escaped control. Applying the preemergence herbicide too early
may also result in less than desirable control. Also, adequate soil mois-
ture prior to and following application is necessary to ensure success, thus
timing for rainfall or irrigation is necessary. Most preemergence herbi-
cides will control germinating weed seeds over a period of six to twelve
weeks. Approximate timing of application of preemergence herbicides is
February 1, in south Florida; February 15 in central Florida; and March 1
in north Florida.
Postemergence Once weeds have germinated and are actively growing,
they must be controlled postemergence. Weeds are generally easier to con-
trol when in the seedling stage and actively growing. These types of herbi-
cides are generally metabolic inhibitors and need time to work on healthy
plants. Applications made to weeds under stress actually may reduce the ef-
fectiveness. Postemergence herbicides may be absorbed through the foliage,
roots, or both and then translocated to the target areas in the plant. Optimum
conditions are necessary to ensure effectiveness of application. If conditions
are dry, irrigation is necessary prior to application to ensure active growth
of the weeds. Irrigation should be withheld immediately following applica-
tion. The area treated should not be mowed for several days after application
to give the chemical time to work.







Weed Control in Newly Planted Lawns

Seeded centipedegrass DO NOT APPLY preemergence herbicides be-
fore or immediately after seeding. Preemergence herbicides may be applied
only after seeded grasses have emerged and are well-established. Control of
annual weeds can best be handled with a preemergence herbicide application
the second growing season or postemergence herbicide application later in
the planting season.
Sprigged, sodded, or plugged centipedegrass and St. Augustinegrass -
Apply preemergence herbicides immediately after planting. Atrazine at
2 lb/A (2.2 kg/ha)* will provide good to excellent weed control with a min-
imum of growth retardation. Other preemergence herbicides such as DCPA
(Dacthal), benefin (Balan), or bensulide (Betasan) will provide good weed
control but moderate to strong inhibition in growth and/or root formation
may occur until turf is established.

Weed Control in Centipedegrass

Preemergence control of many broadleaf and grassy weeds can be attained
by using atrazine either in a"Weed and Feed" formulation (Fertilizer & Her-
bicide) or as a spray application. Postemergence broadleaf weed control is
possible with atrazine applied as a spray. Apply atrazine at a rate of 2 lb/A
(2.2 kg/ha) on sandy soils and 4 to 5 lb/A (4.4 to 5.7 kg/ha) on muck soils.
An application is usually necessary at least every 6 months (spring and fall)
for continued effective preemergence weed control. Use a calibrated sprayer
and 0.5-1.0 gallon of water per 1000 square feet (2-4 L/100m2). Granular
homeowner formulations (Weed and Feed materials) containing fertilizer
plus atrazine are available and are generally effective primarily as pre-
emergence treatments. These must be applied with a calibrated spreader to
ensure optimum application. Make certain that precautions listed on the label
are observed. DO NOT apply around landscape plantings.
Other preemergence herbicides are also effective for both grassy and cer-
tain broadleaf weeds at the rates listed as follows:

Benefin (Balan") 3 lbs/acre (3.36 kg/ha)
Bensulide (Betasan',Presan") 7.5-12.5 lbs/acre (8.4-14 kg/ha)
DCPA (Dacthal") 10-12 lbs/acre (11.2-13.4 kg/ha)

Postemergence control of broadleaf weeds can be obtained with 2,4-D
(amine formulation) applied as a spray at the rate of 0.5 lb/A (0.56 kg/ha).

*All herbicide rates are active ingredient rates per acre. For product rates, check the label.







Dicamba at 0.125 lb/A (0.12 kg/ha) is also effective but the tolerance of the
grass is quite low and careful calibration and application is a necessity. At
these rates repeat applications may be necessary for control of most summer
and winter annual weeds. Additionally, dicamba must be kept away from all
ornamental species since it can be absorbed through the roots. Mecoprop
(MCPP) alone or in various formulations with other herbicides or growth
regulators can be used for broadleaf weed control in centipedegrass and St.
Augustinegrass. All of these herbicides when applied as sprays may injure
ornamentals if the spray drifts onto the foliage. Use caution and avoid spray-
ing during windy conditions. Check the label for application rates and turf-
grass tolerance. With all herbicides, use a calibrated sprayer and 0.5-1 gallon
of water per 1000 square feet (2-4 L/100m2). Centipedegrass is not tolerant
of asulox, arsonates (DSMA, MSMA), paraquat, glyphosate, or dalapon.
Severe injury or death will usually result from application of these herbi-
cides.
Weed Control in St. Augustinegrass

St. Augustinegrass has limited tolerance to phenoxy herbicides (2,4-D
and MCPP) or dicamba. Atrazine can be used in St. Augustinegrass to
control almost all broadleaf weeds and most annual grass weeds if applied
before the weed seeds germinate. Atrazine should be used at rates of 2 lb/A
(2.2 kg/ha) on sandy soil and 4-5 lb/A (4.4 to 5.7 kg/ha) on muck soils. An
application is usually necessary every six months (spring and fall) for con-
tinued effective preemergence weed control. Grassy weeds and certain
broadleaf weeds can also be effectively controlled preemergence by the use
of the following herbicides:
Benefin (Balan'") 3.0 lbs/A (3.36 kg/ha)
Bensulide (Betasan',Presan") 7.5-12.5 lbs/A (8.4-14 kg/ha)
DCPA (Dacthal'") 10-12 lbs/A (11.2-13.4 kg/ha)

Oxadiazon (Ronstar G") 3.0 lbs/A (3.36 kg/ha)

Postemergence control of grassy weeds and selected broadleaf weeds can
be obtained with the use of atrazine and/or asulam (Asulox). Asulam will be
effective on some weeds not controlled with atrazine. Asulam (Asulox")
may be applied alone at 2 lb/A (2.2 kg/ha) or in a combination with atrazine
for broadspectrum weed control each at the 2 lb/A rate (2.2 kg/ha). Herbi-
cides in general should not be applied to freshly mowed turf or to turf under
stress. St. Augustinegrass is not tolerant of arsonates (DSMA, MSMA), pa-
raquat, glyphosate, or dalapon. Severe injury or death will usually result
from application of these herbicides.








Precautions of Herbicide Applications

Proper application includes the use of clean, correctly calibrated equip-
ment. A properly calibrated sprayer or spreader provides for economical her-
bicide use and no injury to turf from excessive rates. The following precautions
must be observed when handling and applying herbicides:


1. READ and OBSERVE instructions and precautions on the herbicide
label.
2. Apply the proper rate of herbicide, to avoid injury to turfgrasses. Mark
off 1,000 square foot areas (or multiple areas for sprayer or spreader ca-
pacity to control proper rate and to ensure good coverage).
3. It is very important, however, to carefully regulate application of correct
rates. For this reason, air pressure-type sprayers are preferred over hose-
end type sprayers, due to less accuracy with hose-end sprayers. Spreader
calibration for Weed & Feed formulations is strongly suggested.
4. Apply herbicides in V2-1 gallon of water per 1,000 square feet (approxi-
mates 20-40 gallons per acre) [2-4 L/100m2].
5. Excessive rates or too frequent applications of atrazine may injure grass
or desirable ornamental plants. Do not exceed 2 lbs/A (2.2 kg/ha) on
sandy soils or 4 lbs/A (4.4 kg/ha) on muck soils or apply more frequently
than every 90 days.
6. The amine form of 2,4-D is preferred over the ester form, because the
amine form is less volatile and presents less hazard due to vapor drift to
desirable ornamental or garden plants.
7. Do not apply atrazine or dicamba under the drip line (within the root
zone) of ornamentals.




Useful Conversions

To Convert Multiply by To Obtain

Pounds/acre 1.12 kilograms/hectare
Pints/acre 1.17 liters/hectare

Pounds product/acre 0.37 oz. wt./1000 square feet
Pints product/acre 0.37 oz. liq./1000 square feet








HERBICIDE APPLICATION IN CENTIPEDEGRASS


Common name
and rate in lbs
active ingredient
per acre


Trade name and
rate of product
per acre


PREEMERGENCE


crabgrass
(Digitaria sp.)


atrazine
(2.0)


benefin
(3.0)


bensulide
(7.5-12.5)


DCPA
(10.5)


Several Brands


Balan 2.5 G
(120 lbs)


Betasan 3.6G
(209-348 lbs)


Dacthal W-75
(14 lbs)


Apply prior to
germination

Do not apply to
immature turf.


crowfootgrass
(Dactyloctenium
aegyptium)

goosegrass
(Eleusine
indica)

annual bluegrass
(Poa annual)

sandbur
(Cenchrus sp.)

water pennywort
(Hydrocotyle
umbellata)

spurges
(Euphorbia or
Chamaesyce sp.)

Florida pusley
(Richardia
scabra or
R. braziliensis)


Same herbicides, rates and comments as crabgrass above.




Same herbicides, rates and comments as crabgrass above.



Same herbicides, rates and comments as crabgrass above.


Same herbicides, rates and comments as crabgrass above.


atrazine
(2.0)


Several brands


Same herbicides, rates and comments as crabgrass above.




Same herbicides, rates and comments as crabgrass above.


Weed Species


Remarks








HERBICIDE APPLICATION IN CENTIPEDEGRASS


Common name
and rate in lbs
active ingredient
per acre


Trade name and Remarks
rate of product
per acre


Same herbicides, rates and comments as crabgrass above.


nutsedge
(Cyperus sp.)


white clover
(Trifolium
repens)


bentazon
(0.75-1.0)


dicamba
(0.125-0.250)





dicamba
(0.125)
+
2,4-D and/or
MCPP
(0.25-0.50)


Basagran
(1.5-2 pts)


Banvel 4S
(0.25-0.50 pts)





Several brands
contain these
mixtures.


Will not control
purple nutsedge.
Repeat appli-
cation if
needed.

Avoid drift. Do
not apply within
the root zone of
shallow rooted
ornamentals.

Observe same
cautions as
dicamba above.
Refer to product
label for rates.
A second appli-
cation 7-14
days later may
be needed.


matchweed
(Lippia
nodiflora)


Several brands


water pennywort
(Hydrocotyle
umbellata)

spurge
(Chamaesyce
sp.)

red sorrel
(Rumex
acetosella)


Same herbicides, rates and comments as matchweed or
white clover.



Same herbicides, rates and comments as white clover.



Same herbicides, rates and comments as matchweed or
white clover.


Weed Species


woodsorrels
(Oxalis sp.)


POSTEMERGENCE


atrazine
(2.0)







HERBICIDE APPLICATION IN CENTIPEDEGRASS


Common name
and rate in lbs
active ingredient


Trade name and
rate of product
per acre


Remarks


per acre


Florida betony Same herbicides, rates and comments as matchweed or
(Stachys white clover.
floridana)

Dichondra Same herbicides, rates and comments as matchweed or
(Dichondra
(Dichondra white clover.
repens)


Weed Species







HERBICIDE APPLICATION IN ST. AUGUSTINEGRASS


Common name
and rate in lbs
active ingredient
per acre


crabgrass
(Digitaria sp.)


atrazine
(2.0)


benefin
(3.0)


bensulide
(7.5-12.5)

DCPA
(10.5)


oxadiazon
(3.0)


Several brands


Balan 2.5G
(120 Ibs)


Apply prior to
germination

Do not apply to
immature turf.


Betasan 3.6G
(209-348 Ibs)

Dacthal W-75
(14 lbs)


Ronstar G
(150 lbs)


crowfootgrass
(Dactyloctenium
aegyptium)

goosegrass
(Eleusine
indica)

annual bluegrass
(Poa annua)

sandbur
(Cenchrus sp.)

water pennywort
(Hydrocotyle
umbellata)

spurges
(Euphorbia or
Chamaesyce sp.)


Same herbicides, rates and comments as crabgrass above.




Same herbicides, rates and comments as crabgrass above.



Same herbicides, rates and comments as crabgrass above.


Same herbicides, rates and comments as crabgrass above.


atrazine
(2.0)


Several brands


Same herbicides, rates and comments as crabgrass above.


Weed Species


Trade name and
rate of product
per acre


Remarks


PREEMERGENCE








HERBICIDE APPLICATION IN ST. AUGUSTINEGRASS


Common name
and rate in Ibs
active ingredient
per acre


Trade name and Remarks
rate of product
per acre


Florida pusley
(Richardia
scabra or
R. braziliensis)

woodsorrels
(Oxalis sp.)


Same herbicides, rates and comments as crabgrass above.




Same herbicides, rates and comments as crabgrass above.


POSTEMERGENCE


bullgrass
(Paspalum
supinum)


asulam
(2.0)


Asulox
(4.8 pts.)


Do not apply to
freshly mowed
turf or turf
under stress.


crabgrass
(Digitaria sp.)

goosegrass
(Eleusine
indica)

smutgrass
(Sporobolus
poiretii)



sandbur
(Cenchrus sp.)

nutsedge
(Cyperus sp.)


Same herbicide, rates and comments as bullgrass above.



Same herbicide, rates and comments as bullgrass above.


asulam
(2.0)


Asulox
(4.8 pts.)


Repeat appli-
cation will be
needed but may
increase turf
injury*


Same herbicide, rates and comments as bullgrass above.


bentazon
(0.75-1.0)


Basagran
(1.5-2 pts)


Will not control
purple nutsedge.
Repeat appli-
cation if
needed.


* Research information indicates that more than one application is needed for control;
however, the label does not suggest more than 1 application per year.
10


Weed Species








HERBICIDE APPLICATION IN ST. AUGUSTINEGRASS


Common name
and rate in Ibs
active ingredient
per acre


Trade name and
rate of product
per acre


dicamba
(0.125-0.250)


Banvel 4S
(0.25-0.50 pts)


Avoid drift. Do
not apply within
the root zone of
shallow rooted
ornamentals.


matchweed
(Lippia
nodiflora)


Several brands
contain these
mixtures.


2,4-D and/or
MCPP
(0.25-0.50)


Several brands


water pennywort
(Hydrocotyle
umbellata)

spurge
(Chamaesyce
sp.)


Same herbicide, rates and comments as matchweed.




Same herbicide, rates and comments as white clover.


Weed Species


Remarks


white clover
(Trifolium
repens)


dicamba
(0.125)


atrazine
(2.0)









IMPORTANT


PESTICIDE PRECAUTIONS
1. Observe all directions, restrictions and precautions on pesticide labels. It
is dangerous, wasteful and illegal to do otherwise.
2. Volatile vapor drift from 2,4-D esters or spray drift from 2,4-D amines,
dicamba, or other phenoxy or benzoic acid compounds may damage
nearby broadleaf plants. Amine forms of 2,4-D can be used with greater
safety near sensitive landscape plants than can other formulations. Apply
pesticides carefully to avoid drift.
3. Do not apply insecticides or fungicides with equipment used for 2,4-D or
related herbicides.
4. Store herbicides behind locked doors in original containers with labels
intact, separate from seed, fertilizer and other pesticides.
5. Use pesticides at correct dosage and intervals to avoid illegal residues or
injury to plants and animals.
6. Destroy used containers in compliance with label directions so that con-
tamination of water and other hazards will not result.


Information contained in this publication should conform to current prod-
uct labels. If product or active ingredient rates are at variance within this pub-
lication, use the product label recommendations, or contact the local county
Extension agent for more up-to-date information.

Trade and brand names are used only for information. The Florida Co-
operative Extension Service, IFAS, and the University of Florida do not
guarantee nor warrant the standard of any product mentioned; neither do they
imply approval of any product to the exclusion of others which may also be
suitable.

Some of the materials recommended in this publication are not available
to homeowners because the materials are restricted use pesticides which re-
quire licensing for application and handling.


























































This public document was promulgated at a cost of $1,552.00 or $.10 per
copy, to provide information on weed control in centipedegrass and St.
Augustinegrass. 9-16M-83


COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLOR-
IDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES,
K. R. Tefertlller, director, In cooperation with the United States I
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, educational Information and other
services only to Individuals and Institutions that function without regard to race, color,
sex 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 Is available from C. M.
Hinton, Publications Distribution 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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