The following are many of the most frequently asked questions about Syngenta's Tenacity herbicide. If you have additional questions please feel free to contact your Syngenta territory manager.
How long before I can seed after making an application?
Seeding can be done the same day as application for labeled turfgrass species; we recommend seeding as close to application time as possible for added performance benefits.
How long after application before rainfall or irrigation can occur?
Tenacity should be rain fast 1 hour after application. Rainfall or irrigation. One hour after application should not affect product efficacy.
How many applications does it take to control bentgrass and Nimblewill?
The label recommends 3 applications, 3 weeks apart. Any reseeding should be done at time of second application.
Are repeat applications necessary for weed control?
Post-emergence weed control, especially for clover, ground-ivy, wild violets and crabgrass will require a 2nd application 2-3 weeks after initial treatment. Larger weeds are more difficult to control and a non-ionic surfactant is needed for weed coverage.
What is the rate per gallon?
The recommended application rate for hand-held or backpack sprayers is 1 teaspoon/2 gal of water, with 3 teaspoons of a good quality NIS (non-ionic surfactant).
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.
What makes Tenacity different than other currently used turf herbicides?
Tenacity is a selective, systemic herbicide that features a 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 labeled turfgrass species.
What is the active ingredient in Tenacity herbicide?
Mesotrione is the active ingredient in Tenacity herbicide.
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 (HRAC group 27) 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. A repeat application at two to three weeks may be required for adequate weed control. Weed control is most effective on young, actively growing weeds. Efficacy will be reduced under moisture stress or from applications to mature weeds.
What turf species can Tenacity be applied to?
Tenacity can be applied to many of the turf types commonly found on fairways, roughs, or for sod production, such as Kentucky bluegrass, perennial ryegrass, tall fescue, fine fescue, and centipedegrass. Lower use rates are recommended for perennial ryegrass, fine fescue, and St. Augustinegrass. Tenacity is not for use on putting greens.
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 home lawns, 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.
Can Tenacity be tank mixed with other herbicides?
Tenacity can be tank mixed with Barricade®, dicamba, carfentrazone, triclorpyr, atrazine, simazine, s-metolachlor, 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.
Spot treatment dilution rates:
