On the 7th day is when Tenacity turns susceptible weeds white. Wait another 14, then do it again. If you applied at the 4 oz rate, you are allowed to do this 2 more times after the second application. Don't understand the fuss about follow up applications when MSMA would require multiple applications before it worked.

 

On the 7th day is when Tenacity turns susceptible weeds white. Wait another 14, then do it again. If you applied at the 4 oz rate, you are allowed to do this 2 more times after the second application. Don't understand the fuss about follow up applications when MSMA would require multiple applications before it worked.

Thanks Doc. It boiled down to .5 tsp per gal. and I added 1.5 tsp adjuvant per gal. because I used a 4 gal BP sprayer. That is the reason for the tsp measurements. Only did 3 gal batches because filling it up to 4 caused too much foam and using the blue turf marker really became messy with the BP filled that close to the top.

 

No worries. I use Tenacity to kill grassy weeds peculiar to Hawaii and the subtropical areas. First application lights things up. Second and third ones cause root death. BTW, I do not see a specific prohibition against using it for blanket applications like the one with Pylex in residential lawns. I let my customer know their weeds are going to get lit up and go for it. All of them are glad I am doing it. They are used to the heavy damage caused by spot applications of Trimec Plus or straight MSMA. What I do with Tenacity is much more selective. No holes left in the lawn.

 

Damn, nobody else uses tenacity? I thought it came out in 2008-2009 or so. Doesn't anyone else have experience besides Doc? Just interested in hearing others experience.
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I've used it and commented on it in several other threads. What kind of daily high temps have you had since spraying? I've had bent turn white (tips) in about 3 days when temps have been above 80 after spraying. Typically that has been in mixed stands of KBG and PRG. My target has been nimblewill and bent. Nimblewill control has been incomplete. Slowed it down and got rid of maybe 2/3 of it with 2 applications, 5 oz/acre 16-21 days apart. Bent control has been excellent. Also, the KBG now makes a stronger or better appearance as it weakened the PRG. It's hard for me to mentally compare my rate over a few acres to yours in a BP sprayer. I'm sure GreenDoctor's remarks about what to expect are correct.

 

I use it on KBG currently for yellow nutsedge. Mix 1 tbs to 2 gallons (if memory serves me) for spot spray. Usually have good results of whitening within a week or less. If it's bad I return after 2 weeks to repeat treatment.
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No worries. I use Tenacity to kill grassy weeds peculiar to Hawaii and the subtropical areas. First application lights things up. Second and third ones cause root death. BTW, I do not see a specific prohibition against using it for blanket applications like the one with Pylex in residential lawns. I let my customer know their weeds are going to get lit up and go for it. All of them are glad I am doing it. They are used to the heavy damage caused by spot applications of Trimec Plus or straight MSMA. What I do with Tenacity is much more selective. No holes left in the lawn.

Do you think it is better to use it at the 4 oz rate multiple times or a single higher rate? Warm season grasses btw.

 

Damn, nobody else uses tenacity? I thought it came out in 2008-2009 or so. Doesn't anyone else have experience besides Doc? Just interested in hearing others experience.
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I'm going to try some on a few patches of bent in a KBG/PRG stand this week as well.

 

First application lights things up. Second and third ones cause root death.

Root death from an HPPD inhibitor? That's a new one.

I noticed your earlier comment regarding the common theme of disappointment that Tenacity requires multiple treatments to work. You're right that MSMA took multiple treatments, but for most of the weeds on the Tenacity label, we can get the same or better control with one application of a cheaper product.

It does have a niche fit (nimblewill, creeping bentgrass, difficult perennial grasses), but I don't think Tenacity is the all-in-one broadleaf + grassy weed control product that Syngenta positioned it to be.

 

I've used it and commented on it in several other threads. What kind of daily high temps have you had since spraying? I've had bent turn white (tips) in about 3 days when temps have been above 80 after spraying. Typically that has been in mixed stands of KBG and PRG. My target has been nimblewill and bent. Nimblewill control has been incomplete. Slowed it down and got rid of maybe 2/3 of it with 2 applications, 5 oz/acre 16-21 days apart. Bent control has been excellent. Also, the KBG now makes a stronger or better appearance as it weakened the PRG. It's hard for me to mentally compare my rate over a few acres to yours in a BP sprayer. I'm sure GreenDoctor's remarks about what to expect are correct.

Temps have been in the 80's with low 60's at night. Kind of a cool spell for the area.

 

Do you think it is better to use it at the 4 oz rate multiple times or a single higher rate? Warm season grasses btw.

All the research I've read say multiple apps at 2-3 intervals is best.

 

Here are some pics after the first blanket app on bentgrass growing in tall fescue. This is the 4 day mark.

 

I think it looks fine. You're on your way. I agree with making that second application as the label recommends. Are you overseeding those areas? If not, is there enough desirable grass growing in the bent patches? These questions are more rhetorical or food for thought rather than so,etching I need or expect an answer on.

 

First app you don't see much, second app and it will really start to bleach out. Third app and you will be spraying mostly white turf with bits of green in it. It is very slow acting on bent. Make three apps 10 to 14 days apart. Expect it to be a multiple year process.

 

I think it looks fine. You're on your way. I agree with making that second application as the label recommends. Are you overseeding those areas? If not, is there enough desirable grass growing in the bent patches? These questions are more rhetorical or food for thought rather than so,etching I need or expect an answer on.

Thanks for posting. Well, some of these patches of bent are really thick mats. I planned it out that after the 3rd app of Tenacity, I am aerating and seeding the next day.

First app you don't see much, second app and it will really start to bleach out. Third app and you will be spraying mostly white turf with bits of green in it. It is very slow acting on bent. Make three apps 10 to 14 days apart. Expect it to be a multiple year process.

Thanks for posting what to expect. You're right, I'm not seeing much and am thinking I did something wrong. So my plan was 3 week intervals for the Tenacity apps. I didn't want to stress the tall fescue too much by applying in too tight of windows. I read online where 2 professors of turf management recommended 3 week wait time between apps. Not saying what you advised is wrong, just saying that's how I came to the 3 week plan. Should I not follow that and move it down to 2 weeks?

Thanks for the info on what to expect

 

I guess it depends some on your plan. If you plan on seeding and if you go three weeks between treatments and make three apps you are getting late in the fall seeding window by the time your apps are made. I wouldn't go three weeks but that is just me and I am far from a professor.

 

I guess it depends some on your plan. If you plan on seeding and if you go three weeks between treatments and make three apps you are getting late in the fall seeding window by the time your apps are made. I wouldn't go three weeks but that is just me and I am far from a professor.

Well the seeding window here is pretty much the last week in August to the second or third week in September. That is Zone 7 by the way. I'll see how it goes, if anything I'm assuming 3 apps should pretty much kill this stuff.

 

Just posting a new pic. One of the many areas of bengrass in fescue. This is Day 9 after Tenacity was sprayed. Starting to see the effects.

 

How does the turf look up close ? Is it white on the tips as well ? Thanks for posting pics

 

How does the turf look up close ? Is it white on the tips as well ? Thanks for posting pics

Hey glad you asked, the entire 13,000 ft.² of turf looks really rough. The bentgrass is getting real white. Most of the tall fescue tips are slightly white, but the overall appearance of the lawn when you drive past is really light green. It was really dark green before I started so I'm hoping everything is okay.
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ok, here are some updated pics taken on day 11 after spraying.

I am getting sick at my stomach that I wrecked my lawn. I've never used Tenacity before so luckily this is my own yard and not someone else's. Am I overreacting? The bentgrass is turning very white but I can tell it needs another app or two. When I put my hand down in it and grabbed it, the inside and towards the bottom didn't look as bad as the tops.

Anyways, I'm concerned about the fescue. It looks as though some blades are turning totally white, not just the tips. You can see from the pics that show the entire lawn area that is has a very light green appearance now. Almost a "mottled" look. Is the fescue going to die or is this just temporary stress?

I figure that the next 2 apps I am not doing a total blanket app. I can really see where the bentgrass is now and will just spray the patches and the areas directly outside of the bent.

I'm thinking that I might have walked too slow while spraying and "over applied" that's why the fescue is so stressed. Can anyone help me out or comment from what you see in the pics?

**You can see in the 3rd pic down that the little patch of grass had NO Tenacity applied to it compared to the big open area. It's not as light as the pic indicates due to the sun. However, the fescue is really turning light green.

**Also, at the bottom left corner of pic 1, the dark area is a shadow from a tree/shaded area.

 

Here are some more pics.....

The first 2 are open shots of the fescue lawn. You can see that "mottled" and light green look I am talking about. Did I ruin my lawn or do you think this is temporary?

The 3rd pic is a close up of a section of fescue. I used exactly the amount of Tenacity that the label said. The ONLY thing I can think of is that I walked way too slowly while spraying. Could that have caused what is shown in the pics and will it be ok?

 

I believe you are ok. Can you confirm rate of first app again? Standby to overseed. Also, if you have wet conditions that favor bent maybe think about trying to dry it out somehow. Don't panic.

 

I believe you are ok. Can you confirm rate of first app again? Standby to overseed. Also, if you have wet conditions that favor bent maybe think about trying to dry it out somehow. Don't panic.

Confirmation of rate used: Very first BP of 1st round application, filled the 4 gallon BP up to the 4 gallon mark. Rates used were 2 tsp Tenacity, 6 tsp of adjuvant (non ionic surfactant) and blue turf marker (1oz per gallon)

All the other refills were only done to the 3 gallon mark of the BP because there was too much foam when filled to the 4 gallon line. I adjusted the rate since I was using 3 gallons of water to 1.5 tsp of Tenacity but I still used 6 tsp of adjuvant rather than decreasing it to 4.5 tsp. I don't think using 1.5 tsp more of surfactant would have made any difference do you?

Anyways, those are the rates used for the tank mix.

 

I'm having a little trouble converting teaspoons to fl oz but read this
http://aroundtheyard.com/northern/topic-t3746-160.html
that can probably help us both. Based on the conversions and dilutions for BP sprayers there it looks as if you were within or slightly below the label rate. Unfortunately, I can't be sure because I don't know how many square feet you covered per gallon.

I'd say you were high on your NIS rate and that could cause some chlorosis if it has been hot and sunny.

My gut tells me you should mow slightly lower than normal and spray again once area is relatively clear of clippings. Understand I have only used this chemical 10-12 times and on multiple acres with larger well calibrated equipment. I have experienced having it not perform as well as I would have liked but never any runaway damage. I continue to think it is more effective for bent and CG post and pre than for well established nimblewill. Bottom line is I think that you are ok and on track to wipe out bent just in time to aggressively grow PRG and KBG in whatever mix you prefer.