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Tenacity Herbicide is a systemic pre-emergent and post-emergent herbicide for the selective contact and residual control of weeds in turfgrasses. Tenacity can be used for weed control prior to or during seeding of certain turfgrasses during renovations. When applied as a pre-emergent, weeds absorb Tenacity during emergence from the soil. Dry conditions following application may reduce the pre-emergence activity. If rainfall (0.15 inches) has not occurred within 10 days after a pre-emergence application, activate with 0.15 inches of irrigation. When used as a post-emergent, Tenacity weed killer is absorbed by susceptible weeds through foliar contact and soil absorption. Foliage of treated weeds cease growth after application, then turn white (loss of chlorophyll) and death may take up to three weeks. A repeat application is required after two to three weeks for improved post-emergence weed control. A non-ionic surfactant should be added in post-emergence applications.
We also offer the Tenacity Herbicide Kit with Surfactant and Spray Indicator Dye which includes one 8 ounce bottle of Tenacity Herbicide, one 32 ounce bottle of Turf Mark Blue Spray Indicator Dye, and one 8 ounce bottle of Hi-Yield Spreader Sticker Non-Ionic Surfactant.
PLEASE NOTE:
Syngenta has recently updated its Tenacity packaging. You may get either the new packaging or the old packaging until all of the old packaging style has been depleted. There is no change to the product itself, only the exterior packaging.
Product Documents
| Active Ingredient | Mesotrione 40% |
|---|---|
| Target pests |
Barnyardgrass, Carpetweed, Chickweed, Clover, Crabgrass (large & smooth), Dandelion, Foxtail, Goosegrass, Henbit, Yellow Nutsedge, Purslane, Thistle, Wild Carrot and others * See label for complete list |
| For use in | Kentucky Bluegrass, Centipedegrass, Buffalograss, Tall Fescue, Perennial Ryegrass, Fine Fescue, St. Augustine Grass (grown for sod only) |
| Application |
4 - 8 oz. per 30 gallons of water per acre * Use a Surfactant to Increase Effectiveness * See label for complete application instructions |
| Formulation |
Professional Product Group 27 Herbicide |
| NOT FOR SALE TO | AK, PR |
| Shelf Life | 3-5 years from date of manufacture when properly stored. Keep out of direct sunlight and extreme temperatures |
| Shipping Weight | 0.81 lbs |
| Manufacturer | Syngenta (Mfg. Number: 46256) |
| EPA Registration | 100-1267 |
Tenacity is a selective, systemic herbicide that features a new mode of action for pre- and post-emergence grass and broadleaf weed control in several cool- and warm-season turf species—like keeping bentgrass out of your rough. Tenacity can also be applied on established or newly seeded turf.
How was Tenacity herbicide discovered?
A Syngenta scientist in California noticed 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.
What is the mode of action of Tenacity herbicide?
Tenacity 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 quickly does Tenacity work?
Once absorbed, Tenacity quickly translocates throughout the plant. Weed growth is suppressed soon after application, as photosynthesis is disrupted. Death of the plant usually occurs within two to three weeks.
What are some of the unique benefits of Tenacity herbicide?
Tenacity has pre- and post-emergence activity on 46 dicot and monocot weed species. It can selectively control perennial monocots such as bentgrass and nimblewill and annuals such as crabgrass and goosegrass in many turfgrass species. Tenacity can be applied at the seeding to prevent weed germination and allow the turfgrass species to establish without weed competition.
Can Tenacity be used to get bentgrass out of roughs and fairways?
Yes. Tenacity selectively controls bentgrass out of Kentucky bluegrass, perennial ryegrass, and tall fescue turf.
What does it mean that Tenacity was granted reduced-risk status by the EPA? Why did Tenacity earn this status?
Reduced-risk is an EPA designated registration status that accelerates the process for registration of certain new plant protection products. Tenacity received reduced-risk status by the EPA based on its unique mode of action, low use rates, and favorable toxicity and human health profiles, as compared to other herbicides currently on the market.
On which grasses has Tenacity been tested for use at or prior to seeding?
Tenacity is safe for use at or prior to seeding on Kentucky bluegrass, tall fescue, perennial ryegrass, and centipedegrass. Application at seeding can be made to fine fescue only if it is less than 20% of a seed mixture.
Are there any grasses on which you can't use Tenacity?
Tenacity is not recommended for use on zoysiagrass, hybrid or common bermudagrass, seashore paspalum, or kikuyugrass.
Can Tenacity be tank mixed with other herbicides?
Tenacity can be tank mixed with Barricade, dicamba, carfentrazone, triclorpyr, atrazine, simazine, s-metolachlor, bentazon, and several three-way phenoxy herbicides. Combinations can help turf managers broaden the weed control spectrum or improve the level of weed control over single-product applications.
How rainfast is Tenacity?
Tenacity is rainfast within several hours under normal rainfall conditions.
What other brands currently on the market offer a product similar to Tenacity?
There are currently no other herbicides like Tenacity for golf courses and sod farms registered for use or sale in the U.S. Tenacity will compete with multiple products from different classes of chemistry.
Tenacity Herbicide
By Frank on 05/07/2012
Verified Purchase
I had a lot of weed grasses in my yard and they were invasive and spreading over the whole yard. Tenacity targets weed grasses and kills them while leaving the rest of the yard in tact and that is exactly what it did. All of my weeds are dying. One thing you must note is that this herbicide needs to be watered after it dries on the plant so that the plant takes it in. It will not work if you just spray it on and don't get rain or water it for a couple of weeks. It's pricy but I know of no other chemical that will kill weed grasses and leave what you want, alone.
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632 of 661 people found this review helpful
A Miracle Herbicide!
By Margaret on 08/14/2012
Verified Purchase
I had a lawn that was completely taken over by bentgrass. I used round up on the lawn and put in an entire new lawn. All was well for a year or two. Then the the bentgrass came back in a few isolated areas. I would have to round them up at the end of the season and reseed. This went on for a number of years. When I learned about Tenacity I was thrilled and gave it a try. It works wonderfully! Yes it is pricy, however it beats having to round up the bentgrass, clear it out, put down more top soil and reseed. Try it...you won't be disappointed.
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400 of 416 people found this review helpful
Death of Nimblewill grass
By David on 10/02/2015
Great product! Does exactly what it advertises!
By Debi on 09/07/2012
My mom completely re-sodded front and back lawns and within 3 years it had been invaded by bentgrass. My new lawn was hydro-seeded 5 years ago in a new subdivision that used to be a golf course. Our methodology was to use Roundup in the fall (when the bent grass really seems to take off in growth) and then reseed the large killed off areas, hoping that the Roundup did a thorough job in killing the bentgrass. This becomes very tedious every year, not to mention the expense. We waited a few years for Tenacity to be available to the public and have both been having great results with the product. The good thing is that the remaining blades of good turf remain green in the kill zone. That gives me hope that I may not have to reseed, just wait for the good turf grass to fill in by itself. Our lawns are a combination kentucky blue and fescue blends. My only complaint is that the product is so concentrated and thick. The high concentration makes it even more critical to measure accurately! Not too crazy about the enclosed syringe measuring device. I feel it is too difficult to use and the potential to spill is high. I would love if there could be a more diluted Tenacity product to purchase for the average homeowner. That would make the product easier to measure, plus ensure a bit of wiggle room on the measurements?
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330 of 356 people found this review helpful
No more Crabgrass!!
By Rob on 08/23/2012
Verified Purchase
Just over seeded and my new grass is starting to grow. Can i use this product without hurting my new grass?
Can I mix tenacity with organic liquid fertilizer and liquid humic acid at the same time or just one at a time? It would be so helpful if I could do both at the same time.
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Since Tenacity Herbicide requires a surfactant as a post-emergent, we would not advise mixing it with a product that does not require one. If both products require a surfactant, you would need to a jar test to see how they both react together. Keep in mind that as a post-emergent it can only be spot treated & not blanked sprayed the way other post-emergents can
If I pre germinate my rye grass seed & plant them when roots are just starting to form, can I apply Tenacity at the same time or would I need to apply Tenacity before I plant them?
Tenacity Herbicide is best applied 2 weeks before planting/seeding a lawn or wait at least 2-3 weeks after seeding to apply. When pre-germinating and planting in the area we would recommend waiting at least 4 weeks to apply so it is established.
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3 of 4 people found this answer helpful
Tenacity Herbicide cannot be used on home lawns that have St Augustine. It is only for use on St Augustine in sod farms.
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Tenacity Herbicide is not labeled for clump fescue, and it is safe for tall fescue.
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I'm in South Carolina and have Centipede grass that has some patches of Japanese clover growing in it.
Ideally, you would not want to put a fertilizer down when the lawn is getting ready to go dormant. If anything, an application could be made now in early October as your last treatment for the year. Tenacity would not be effective on lespedeza (japanese clover) at all as its not labeled for it. Southern Ag Atrazine is labeled for lespedeza and is safe for use on Centipede lawns if used as directed. Another option is Fertilome Weed Free Zone.
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0 of 1 people found this answer helpful
I applied a broadcast application of tenacity on 8/29 in TN. I have approximately 7000 square feet. I put out the spot treatment formula instead of broadcast formula so I don't think I put out enough. I overseeded on 9/23. I have a 2 gallon sprayer. How much tenacity do I put into the sprayer with 2 gallons of water? Math is hard:). My goal is to control poa annua. I plan on putting out dimension as well in a few weeks.
Tenacity Herbicide can be applied at the same time as seeding (unless grass is more than 20% stand of fine fescue). If application cannot be done within 7 days of seeding you would need to wait a minimum of 30 days, or until the seed has emerged and been mowed at least twice before applying to the lawn.
According to the Tenacity product label, you will need to mix 1 tsp of product + 3 tsp surfactant with 2 gallons of water for spot treatments applied at a rate of 1 gallon per 1,000 sq ft. It is advised to use a dye like Turf Mark Blue with it so you can make sure to not overlap if you plan to do a broadcast application on the property. Repeat applications can be done after two to three weeks for continued post emergent weed control.
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It would be best to wait to apply Tenacity Herbicide until the grass has completely dried before the application. Be sure to mix in a Non Ionic Surfactant when doing post emergent applications.
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2 of 4 people found this answer helpful
I seeded on the 8th of September and have good growth, but also I have many weeds just starting to pop up. How long should I wait to apply tenacity so that it won't harm the tall Fescue?
For post emergent applications with Tenacity Herbicide with adding a Non Ionic Surfactant, the product label states to wait until the newly germinated turf has been mowed two times or four weeks after emergence (whichever is longer) before treating actively growing weeds.
For pre emergent applications with Tenacity Herbicide, apply Tenacity before or at the same time of seeding for best results. The key time to avoid spraying Tenacity on new seedings, either as a pre-emergent or a post-emergent, would be when the new seedlings have started to come up but are not yet established.
Please refer to page 12 of the product label for complete application instructions around seeding.Lawn has quickly developing quack grass. Does Tenacity works post emergence for this weed? I must try something immediately.
Tenacity Herbicide is not labeled for quackgrass as a pre or post emergent. Unfortunately, we do not currently carry any products that are labeled for quackgrass that are safe for use in cool season grass.
We would recommend spot treating with something like Roundup QuikPRO and then reseeding any bare spots after 2 weeks.
View our Quackgrass Treatment Guide for more information.
When using Tenacity Herbicide as a pre-emergent and seeding, you can apply Tenacity before or at the time of seeding for best results as long as you are planting a turfgrass that is listed as tolerant on the product label (Kentucky bluegrass and tall fescue are tolerant).
The key time to avoid spraying Tenacity on new seedings, either as a pre-emergent or a post-emergent, would be when the new seedlings have started to come up but are not yet established. Once you see new seedlings, you would want to wait at least four weeks or until the new grass has been mowed twice, whichever is longer. Please refer to page 12 of the label for complete application instructions around seeding.
Any pets (including chickens) would need to be kept out of the area while spraying Tenacity Herbicide and kept out until the application has completely dried. Once dry, it would be safe to allow pets and chickens to resume normal activity.
Please view the full product label for more information.
To control nimblewill, start applying Tenacity in the spring (late-April) with a nonionic surfactant. You will need to make two or three applications 2-3 weeks apart. You will use it at the 5 oz per acre rate per the label. The product does have a yearly maximum use rate, and the label states "do not apply more than 16 oz of Tenacity per acre per year or per crop (equivalent to a maximum of 0.50 lb of mesotrione per acre per year).You can also apply Tenacity in late summer and fall, but you should initiate them by August for best results. Good cultural practices on your lawn can help reduce its ability of coming back as well.
Tenacity Herbicide
Rating: 4.3 (615 Reviews / 662 Q&A)
