What is Tenacity?
herbicide is a new tool for lawn care operators for pre- and post-emergence
weed control on cool-season turfgrasses such as tall fescue perennial ryegrass
and Kentucky bluegrass.
Granted reduced-risk status by the
U.S. Environmental Protection Agency (EPA),
on turf) can be used at seeding, including bare-ground seeding, or selective renovations and overseeding. It keeps weeds from germinating and allows new grass to flourish.
What does it mean when the EPA says that Tenacity was granted Reduced
Risk status? How did Tenacity earn this status?
The active ingredient in Tenacity, mesotrione, has been granted
Reduced Risk status by the EPA for turf use.
It has favorable ecotoxicity and human health profiles, compared to many
registered herbicides, which result in a reduction in the herbicide load on the
environment. Its mode of action is
novel among turf herbicides, and it fits well into IPM and resistance
Reduced Risk pesticide use is defined as one which may reasonably be expected
to accomplish one or more of the following: (1) reduces pesticide risks to
human health; (2) reduces pesticide risks to non-target organisms; (3) reduces
the potential for contamination of valued, environmental resources, or (4)
broadens adoption of IPM or makes it more effective.
Mesotrione qualifies under one or more of the above criteria.
How does Tenacity work? What is the mode of action?
Tenacity with a
group 27 mode of action inhibits a plant enzyme called HPPD that is
essential to photosynthesis and prevents formation of carotenoids in
susceptible plant species. Without carotenoids, light energy and by-products of
photosynthesis will destroy chlorophyll and cell membranes. This results in bleaching of leaves, followed by necrosis and
death of the plant.
How was Tenacity herbicide discovered?
A Syngenta scientist in California
observed that there were fewer weeds growing under his
bottlebrush (Callistemon citrinus) plant, far fewer than can be
explained by shading alone. He concluded that the plant must be producing
allelochemicals to suppress weed competition. Syngenta synthesized mesotrione,
based on the allelochemicals produced by the bottlebrush plant.
How quickly does Tenacity work?
Once absorbed, Tenacity quickly
translocates throughout the plant. Weeds stop competing with the desirable turf
soon after application, as photosynthesis is disrupted. Death of the unwanted
plant usually occurs within two or three weeks.
What weeds does Tenacity control?
Mesotrione, the active ingredient in Tenacity, controls 46 dicot and
monocot broadleaf, sedge weeds and grasses, including nimblewill, crabgrass,
bentgrass, ground ivy, yellow foxtail and yellow nutsedge.
Lawn care operators and their customers may see some bleaching or
“whitening” of weeds after an application of Tenacity. Is that normal?
A Yes — it means that Tenacity is working. Some degree of turf bleaching is to
be expected when using the product, since its mode of action
inhibits the enzyme that is essential to photosynthesis in susceptible weed species. This results in bleaching of unwanted weeds,
followed by necrosis and death of the plant. Occasionally, white tips can also
be seen on desirable grasses
following treatment. This is a temporary symptom, as the tips will be removed
during subsequent mowings.
Why is Tenacity different than other turf herbicides currently used by
lawn care operators?
Tenacity lets lawn care operators do things for their customers they haven’t
been able to do before. It provides cost-effective pre- and post-emergence
control over a wide range of weeds and undesired grasses — including nimblewill
and bentgrass. Additionally, it provides an outstanding up-sell opportunity for
selective renovations and overseeding
of established turf. Not
only does Tenacity drive incremental revenue, but it helps reduce
profit-robbing customer call-backs. There simply is
no other herbicide available today that does all that.
On which turf species can Tenacity be used?
Tenacity can be applied to many of the
most common turf types such as Kentucky bluegrass, perennial ryegrass, tall
fescue, fine fescue, centipedegrass and buffalograss.
Lower use rates are recommended for perennial ryegrass and
may be used at and before seeding on Kentucky bluegrass, tall fescue, perennial
ryegrass, and centipedegrass. Application at seeding can also be made to seed
blends of fine fescue if the fine fescue is less than 20% of the seed mixture.
Can Tenacity be tank mixed with other herbicides?
Yes it can. Tenacity can be tank-mixed with
Pennant Magnum®, dicamba, carfentrazone, triclorpyr,
atrazine, bentazon and several three-way phenoxy herbicides. Combinations can
help professional lawn care operators broaden their weed control capabilities.
See label for specific rates on tank-mixes.
information about Tenacity can be found at: www.TenacityHerbicide.com
How rainfast is Tenacity?
Tenacity is rainfast one hour after application.
How will Tenacity be packaged?
For convenience and ease-of-use, Tenacity will be available in an eight-ounce
bottle. This pack size was designed
to fit the needs of lawn care professionals – the price per container is
reasonable and one container can spot-treat numerous lawns.
What is the anticipated sell date and ship date for Tenacity?
Tenacity in an 8 ounce bottle will be available April 1, 2011 and can be
purchased by lawn care companies through authorized Syngenta agents and
with all pesticides, it is important to read and follow label instructions when
is one of the world's leading companies with more than 26,000 employees in more
than 90 countries and is dedicated to one purpose: Bringing plant
potential to life. Through world-class science, global reach and commitment,
Syngenta assists customers increase crop productivity, protect the environment
and improve health and quality of life. For more information about Syngenta,
please go to
©2011 Syngenta Crop Protection, LLC., 410 Swing Road, Greensboro, NC 27409. Important:
Always read and follow label instructions before buying or using Syngenta
products. The label contains important conditions of sale, including
limitations of remedy and warranty. Tenacity is not currently registered for use or sale in all states. Please check with your state or local extension service
prior to buying or using this
product. Barricade®, Pennant Magnum®, Princep®,
Tenacity® and the Syngenta logo are trademarks of a Syngenta Group