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 *Landscape Topic*

*An Outreach of the UGA Center for Urban Agriculture -
**www.gaurbanag.org*<http://www.gaurbanag.org/>
**

* *

*New Herbicides for Weed Control in Turf*

*Dr. Patrick McCullough, Extension Weed Specialist, University of Georgia*

*Jan**uary 7, 2009*

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The introduction of new turf herbicides will continue to enable
practitioners to control troublesome weeds.  In 2010, turf managers will see
several new options for weed control from novel active ingredients,
combination products, and label amendments.  The following contains an
unbiased view on these products and discusses efficacy for turfgrass weed
control.

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*Celsius (thiencarbazone + iodosulfuron + dicamba)*

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*Celsius *(68 WDG) is a new combination product for postemergence weed
control from Bayer.  Thiencarbazone and iodosulfuron are two new active
ingredients in turf while dicamba is an older chemistry used for broadleaf
weed control.  Celsius is intended for commercial use by licensed
applicators on residential lawns, golf courses, sports fields, parks, sod
farms, and other turf areas.  Celsius will be labeled at 2.5 to 7.4 oz of
product per acre for use in common and hybrid bermudagrass, buffalograss,
centipedegrass, St. Augustinegrass, and zoysiagrass with activity on
numerous annual and perennial broadleaf weeds.**

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Celsius has several promising aspects that practitioners will find
beneficial in weed management programs.  Herbicide selection for southern
lawns with mixed turf species, such as centipedegrass and St.
Augustinegrass, has been limited due to differential species tolerance to
herbicides.  Celsius will be applicable in mixed lawns containing labeled
turfgrass species.   However, bahiagrass and seashore paspalum are sensitive
to applications and Celsius will not be applicable if these grasses are
considered desirable species.  This activity on *Paspalum* species may have
potential to control or suppress several troublesome weeds.**

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For example, Celsius has shown to effectively control bull paspalum and in
limited testing suppressed dallisgrass.  Although registered rates will
probably not control mature populations, Celsius may have potential for use
in programs with other herbicides, such as formasulfuron (Revolver), for
sequential applications to replace MSMA in dallisgrass control regimes.



Preliminary university experiments with Celsius have also shown activity for
crabgrass control.  However, this activity appears to be limited to young
populations of large crabgrass only.  Other crabgrass species, such as
blanket crabgrass, have shown erratic control from Celsius and further
research is needed to investigate efficacy and application regimes.  New
herbicides, like Celsius, with activity on grassy weeds will be significant
for use in St. Augustinegrass and centipedegrass lawns due to limited
products safe for use at rates required for weed control.  **



*Katana (flazasulfuron)*

* *

*Katana* is a new sulfonylurea herbicide from PBI Gordon that will be
available in March 2010 for use in bermudagrass, centipedegrass, and
zoysiagrass.  Katana contains a new active ingredient, flazasulfuron, and
will be formulated in a 25% dry flowable formulation.  Katana has
postemergence activity on numerous broadleaf and grassy weeds including
clovers, dandelion, common chickweed, perennial ryegrass, annual bluegrass,
and tall fescue.  Katana efficacy on perennial ryegrass will aid in
transition of overseeded bermudagrass in the spring and control ryegrass
“clumps” in undesirable locations.  In Georgia, Katana has shown excellent
perennial ryegrass control (90% or greater) in spring with rates greater
than 1 oz of product per acre but efficacy is generally less significant on
annual bluegrass.  Applying granular urea fertilizer at 1.5 lb per 1000 sq
ft before Katana applications has shown to significantly improve activity on
both species, compared to Katana alone, and may shorten transition time back
to bermudagrass.



Katana also controls annual sedges, yellow nutsedge, purple nutsedge, and
several *Kyllinga* species.  In preliminary experiments, repeat applications
of 0.5 oz of product per acre completely controlled purple nutsedge and
perennial *Kyllinga*, similar to halosulfuron (SedgeHammer).  Katana will
likely have similar turf species limitations and uses in weed control
programs similar to trifloxysulfuron (Monument) but with greater spectrum of
broadleaf weeds controlled.

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*Tower (dimethenamid)*

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*Tower* is a new preemergence herbicide released in 2009 by BASF for use on
golf courses.  Tower is a 6L formulation and contains dimethenamid-P, a new
active ingredient for turfgrass.  Tower is labeled for major cool-season and
warm-season turfgrass species and may be applied to golf course fairways,
tees, and roughs.  Preemergence Tower applications effectively control
annual sedges, annual Kyllinga, goosegrass, and selected broadleaf weeds.
Tower also has activity for preemergence yellow nutsedge control but is not
effective against purple nutsedge.  A major limitation to Tower is the
activity on crabgrass.  However, Tower may be used with other preemergence
herbicides, such as pendimethalin (Pendulum) to improve efficacy when
targeting crabgrass and other annual weeds.



Currently, Tower is labeled for golf courses only but future label
amendments will likely add other turf areas.  At this time (January 2010),
Tower is not labeled for residential turfgrass, lawns, recreational
turfgrass, sod farms, or any other turfgrass areas besides golf courses.
Field research is currently being conducted at the University of Georgia to
evaluate the use of Tower during turfgrass establishment.  These trials are
investigating reseeding intervals for perennial ryegrass and the effects of
rate, formulation, and application timing on ultradwarf bermudagrass and
seashore paspalum putting greens.



*T-Zone (triclopyr + sulfentrazone + 2,4-D + dicamba)*

* *

*T-Zone* is a new combination herbicide from PBI Gordon for postemergence
broadleaf weed control.  T-Zone contains triclopyr, sulfentrazone, 2,4-D,
and dicamba at 0.5, 0.06, 1.75, and 0.2 lb/gallon, respectively.  T-Zone is
labeled at 3.25 to 4 pints per acre for broadcast applications to
bluegrasses, ryegrasses, and fescues.  Bermudagrass, bahiagrass, and
zoysiagrass may be treated during *full* *dormancy* at 2 to 2.25 pints per
acre.  Dormant applications to warm-season turfgrasses are recommended due
to the presence of triclopyr in this product.



T-Zone has activity on numerous broadleaf weeds and may be used for
residential turf, sod farms, golf courses, sports facilities, non-croplands,
and other institutional sites.  For golf courses, T-Zone may be applied to
fairways and roughs only.  Avoid applications when temperatures exceed 85°
or to actively growing warm-season turfgrasses.  For best results, do not
mow two days before or after applications and wait until after the second or
third mowing to use on newly seeded turf.



*New Quinclorac Combination Products*



*Quinclorac *is a unique herbicide for grassy and broadleaf weed control
that has been used for several years in turf as Drive 75 DF.   Drive XLR8 is
a new liquid formulation with 1.5 pounds of quinclorac per gallon.  Both
Drive formulations effectively control crabgrass, foxtail, clovers,
torpedograss, and other broadleaf weeds in certain warm and cool-season
turfgrasses.  Since quinclorac is compatible in tank-mixtures with growth
regulator herbicides, combination products containing quinclorac and other
active ingredients have been recently released for use in turf.



*One Time *contains quinclorac, dicamba, and MCPP and provides a better
spectrum of broadleaf weeds controlled than Drive alone.  One Time
applications at 64 fl oz per acre will deliver 0.75 lb a.i. per acre of
quinclorac, which is needed to provide a standard rate of Drive for
crabgrass control.   However, lower use rates of One Time for sensitive
species, such as creeping bentgrass, will generally not deliver enough
quinclorac for effective grassy weed control.  *Solitaire *(quinclorac +
sulfentrazone),* Q4 *(quinclorac + sulfentrazone + 2,4-D + dicamba),* *and *
Quincept* (quinclorac + 2,4-D + dicamba)* *are relatively new combination
herbicides that may provide excellent broadleaf weed control with activity
on grassy weeds.  However, these products may lack sufficient concentrations
of sulfentrazone or quinclorac for controlling sedges and crabgrass,
respectively, at rates safe for use in cool-season grasses.  Always read
product labels carefully before making applications to understand the
limitations of combination products on specific weeds.  Turf managers may
wish to add more herbicides, such as sulfentrazone (Dismiss), if components
are lacking in prepackaged mixture herbicides.

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*Label Amendments for 2010*

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Syngenta has received approval for label amendments for *Tenacity *(mesotrione)
in 2010.  The label amendment will permit future Tenacity use on golf
courses, sod farms, athletic fields, parks, commercial areas, cemeteries,
airports, and lawns.  Buffalograss will also be added to the Tenacity label
as a tolerant turf species at 5 to 8 fl oz/acre.  Another label amendment
will include Tenacity applications to dormant bermudagrass at 5 fl oz/acre
for winter weed control.  *Monument* (trifloxysulfuron) has also received a
label amendment for use on residential turf and athletic fields.



Label amendments for new or old products may continue throughout the year.
It is important for turf managers to read and follow label directions for
all pesticides to understand new uses, new formulations, or potential
restrictions of these products.  Subscribers to “Turfgrass Management”, the
smart phone application released by the University of Georgia, will have up
to date label changes on the program when amendments are released.  Other
label changes during the year will be published in the 2011 pest control
handbook.

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*Note on Products Mentioned*

Listing of pesticides and other chemicals implies no product endorsement by
the University of Georgia or its representatives. Omission and criticism of
products not mentioned is neither implied nor intended. The University of
Georgia does not accept any responsibility for omissions, errors or future
amendments. Always observe directions, restrictions, and precautions on
product labels.



*Please share this information with others in the landscape & turf industry.
For more information:*



Call your local Extension Agent at (800) ASK-UGA1 or locate your local
Extension Office at http://www.caes.uga.edu/extension/statewide.cfm



www.georgiaturf.com



*Pest** Management Handbook* (Follow all label recommendations when using
any pesticide) - www.ent.uga.edu/pmh/





-- 
Dr. Teri Hamlin
North Region Agriculture Education
Georgia Department of Education
204C Four Towers University of Georgia
Athens, Ga 30602
706-542-3679 / 706-540-0032
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