Leaf mulching questions: fungus and poa annua

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Dargin
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Leaf mulching questions: fungus and poa annua

Post by Dargin » September 12th, 2018, 9:54 am

Are there any fungal diseases of leaves that would make mulching a bad idea? I've noticed black spots on many of the leaves dropping around my property. I'm unsure if there are cases where this could introduce fungal issues in the lawn.

I also have a small amount of Poa Annua that I've been treating with tenacity. Made a lot of progress knocking it back and suppressing it since last fall, but I've had to avoid mulch mowing all year to avoid spreading it. Does the presence of Poa Annua mean mulching leaves is off the table? Or would it be reasonable to cut and bag as normal, and then raise the HOC to mulch the leaves afterward?

Appreciate any input. Thanks.

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Re: Leaf mulching questions: fungus and poa annua

Post by andy10917 » September 12th, 2018, 10:11 am

I've noticed black spots on many of the leaves dropping around my property.
Are they Maple leaves, perhaps?
Does the presence of Poa Annua mean mulching leaves is off the table?
Poa Annua should not be seeding at this time, and doesn't spread by stolons/rhizomes - you should be OK. Just be sure it's not Poa Triv.

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Re: Leaf mulching questions: fungus and poa annua

Post by Dargin » September 12th, 2018, 11:45 am

Image
Green light?

It's amazing how many times I can read about a topic and still walk away with the wrong idea... I was certain Annua could be spread by stolons. Thanks for the info, Andy.

If there's triv in the mix, I haven't been able to identify it. There's really no noticeable patches of light green anywhere; the seed heads alone caught my eye. I'm guessing my aggressive dethatching last fall may have kicked up some problems. The lawn hadn't been more than mowed in the decade prior. I've just treated very small, scattered areas that had seed heads popping up. They definitely weren't kbg seed heads, and if my info is correct I wouldn't be seeing triv seed heads at 3 1/2 inches. I treated with tenacity in the spring and put my fall preemergent down on 8/30. I'm currently followinging up with spot applications at 4oz rate every 10 days. I plan to start spring off with a diagnostic dose to see where I'm at.

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Re: Leaf mulching questions: fungus and poa annua

Post by andy10917 » September 12th, 2018, 12:21 pm

Maples can develop a fungal thing called "Tar Spot" that is more cosmetic than serious. It winters-over in the fallen leaves and can reinfect the tree next year. I doubt that mulched leaves that have have disintegrated make a good home.

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Re: Leaf mulching questions: fungus and poa annua

Post by northeastlawn » September 12th, 2018, 1:32 pm

I just wanted to chime in that I am also from Mass. and it seemed like POA annual in my yard that survived the spring tenacity treatments were seeding a few weeks ago. It might have been triggered by the tenacity application I put down or maybe just my wishful thinking that’s it’s not triv. But I noticed seed heads.

The culprit weed pulls out very easy, it’s shallowed rooted, and doesn’t seem to growing horizontal. They are like clumps, not bright lime green, but a shade darker than the KBG.

What would produce seed heads in August?

It certainly seems like the POA annua seed heads from the spring.


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andy10917
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Re: Leaf mulching questions: fungus and poa annua

Post by andy10917 » September 12th, 2018, 3:17 pm

Tenacity can create Poa Annua seedheads as the plants "panic" to set seed in stressful conditions (getting killed is stressful, I hear)...

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Re: Leaf mulching questions: fungus and poa annua

Post by ken-n-nancy » September 12th, 2018, 3:54 pm

northeastlawn wrote:
September 12th, 2018, 1:32 pm
The culprit weed pulls out very easy, it’s shallowed rooted, and doesn’t seem to growing horizontal. They are like clumps, not bright lime green, but a shade darker than the KBG.
That sure sounds like poa annua to me. Although most poa annua seed heads form in the spring, stressed plants will produce seed heads in any season.

The Tenacity application probably caused the production of the seed heads.

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Re: Leaf mulching questions: fungus and poa annua

Post by TimmyG » September 12th, 2018, 4:46 pm

ken-n-nancy wrote:
September 12th, 2018, 3:54 pm
northeastlawn wrote:
September 12th, 2018, 1:32 pm
They are like clumps, not bright lime green, but a shade darker than the KBG.
That sure sounds like poa annua to me.
Except, did he mean to write a shade lighter than KBG or a shade darker?

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Re: Leaf mulching questions: fungus and poa annua

Post by northeastlawn » September 12th, 2018, 5:01 pm

My mistake I meant a shade lighter than the KBG. Ill leave Dargin's thread alone now, just wanted to point out that the POA annua in my yard was generating seed heads and actually pierced up by the 3rd our 4th week of August.

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Re: Leaf mulching questions: fungus and poa annua

Post by andy10917 » September 12th, 2018, 5:06 pm

With your permission, I could change it to "lighter"

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Re: Leaf mulching questions: fungus and poa annua

Post by Dargin » September 12th, 2018, 6:26 pm

It's funny you brought that up, NortheastLawn. I almost mentioned in my 2nd post that I noted seeing some (literally 8) unexpected seed heads into early august. I had read somewhere on here that Poa Annua could do that, but didn't know of a connection to tenacity. Good stuff.

Hopefully this isn't drifting too far from the original subject, but...
I've read tons of threads here on the subject of poa triv. I'm as sure as I can be that I'm in the clear at the moment, but it does bring up a question or two. I have it in my head that poa triv needs to be nearly twice my typical lawn height to go to seed, and that it really only spreads via introduction of contaminated seed and through stolons (from unbagged clippings). Are there any conditions that would cause poa triv to produce seed at say 4 inches? Just curious if it -ever- happens. And is it known if tenacity can cause the poa triv to go to seed the same as it can to poa annua, even at 4 inches or so?

Thanks again for the info, all. Looking forward to putting those leaves to work!

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Re: Leaf mulching questions: fungus and poa annua

Post by ken-n-nancy » September 12th, 2018, 6:37 pm

Dargin wrote:
September 12th, 2018, 6:26 pm
... I have it in my head that poa triv needs to be nearly twice my typical lawn height to go to seed, and that it really only spreads via introduction of contaminated seed and through stolons (from unbagged clippings). Are there any conditions that would cause poa triv to produce seed at say 4 inches? Just curious if it -ever- happens. And is it known if tenacity can cause the poa triv to go to seed the same as it can to poa annua, even at 4 inches or so?
I personally have dealt with a fair bit of poa trivialis in my lawn, but as far as I can remember, I don't remember ever seeing any seedheads on any of it.

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Re: Leaf mulching questions: fungus and poa annua

Post by TimmyG » September 12th, 2018, 9:20 pm

I have never seen Poa trivialis produce seedheads. I, too, have tons of it and have hit it with Tenacity year after year (collateral damage or just out of spite), both spring and fall. This far north, Poa annua produces seedheads whenever it feels like it after the late spring flush.

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Re: Leaf mulching questions: fungus and poa annua

Post by ken-n-nancy » September 12th, 2018, 9:54 pm

TimmyG wrote:
September 12th, 2018, 9:20 pm
I ... hit [poa trivialis] with Tenacity year after year ... just out of spite, both spring and fall.
Ooh, I definitely dislike poa trivialis enough to do that, too. Sounds like a good enough reason to me!

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Re: Leaf mulching questions: fungus and poa annua

Post by Dargin » September 13th, 2018, 10:00 am

ken-n-nancy wrote:
September 12th, 2018, 6:37 pm
Dargin wrote:
September 12th, 2018, 6:26 pm
... I have it in my head that poa triv needs to be nearly twice my typical lawn height to go to seed, and that it really only spreads via introduction of contaminated seed and through stolons (from unbagged clippings). Are there any conditions that would cause poa triv to produce seed at say 4 inches? Just curious if it -ever- happens. And is it known if tenacity can cause the poa triv to go to seed the same as it can to poa annua, even at 4 inches or so?
I personally have dealt with a fair bit of poa trivialis in my lawn, but as far as I can remember, I don't remember ever seeing any seedheads on any of it.
Right on. I've been following your reno thread so I'm well aware you're no stranger to dealing with poa triv. Appreciate the info. Thanks again, all.

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Re: Leaf mulching questions: fungus and poa annua

Post by Dargin » September 14th, 2018, 5:55 pm

Actually caught another one just today, from one of the same areas of lawn that's been an issue. The area was spot sprayed with tenacity about 5 days ago and no seed heads were present:

Image

Although it's a bit mangled, this is the stuff I've identified and have been treating as poa annua. Just to be safe, can anyone confirm the ID from this image? It seems to match up perfectly with many poa annua seedhead images I've seen.

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