# Dying grass again



## 2L8 (Mar 18, 2019)

The lawn here suffers from autumn in large parts from a disease or something that I have not yet identified. In the fall of 2020, I had already opened a topic on this (https://thelawnforum.com/viewtopic.php?p=328819#p328819). I am guilty of the result of the laboratory test. No fungus was found. Previously, anthracnose had been suspected on the basis of the pictures.

The lawn did recover the next year and it looked good in 2021 until the end of November, but then followed a very significant deterioration. It seems to me that the plants died completely and holes appeared in the lawn.At the end of November only a limited region was affected, but by now the discoloration is noticeable almost everywhere in the tall fescue/grassgrassgrass.

Seedings from last October still look fine, but areas from July are already affected.

Here is the development of the most affected region:

 Septenber, 9th 2021
 November, 24th 2021
 December, 15th 2021
 January, 18th 2022
 Detail, December, 15th
 Soil January, 25th 2022

After appearance I had treated parts on November, 27th with azoxy, others with fosetyl, the rest not at all. The area where I applied azoxy has developed the worst. The area shown is located there.
 January, 18th, left to the previous images, azoxy on the right half, fosetyl on the left

Elsewhere, however, azoxy and fosetyl have had no effect. Here is a less infested area:
 January, 19th 2022
Unlike 2020, I had fertilized 2x instead of 1x monthly with half the amount of nitrogen (2.5 g N/m², 0.5lb/1000ft²) and the weather was cooler and wetter. The rainfall in October and November was below average, in December just above average. However, there have been few dry days since November and the grass has often been wet for days. Until the appearance had only minimal frost (-1 °C, 30 F).

Someone suspected snow mold, but I never observed any mycelium.


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## Stuofsci02 (Sep 9, 2018)

Are you sure this is just not "winter". Minimal daylight and cold weather will affect the turf.


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## ABC123 (Jul 14, 2017)

Deadlawn said:


> Here is something I found on this site that may be helpful regarding soil temp and turf growth:
> 
> "The following is a partial list of soil temperatures (F) at the 4-inch depth that should be of the association with certain biological events.
> 
> ...


Its Probably just cold.


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## 2L8 (Mar 18, 2019)

If it was just lack of light and cold, all areas should look the same, or those in the shade the worst. The left area on the second to last picture gets less light than the right one because of a building about 5 feet to the left (south is also left), but it looks better.

The reason for my assumption that it is a fungus is because of the way it appears as single spots, while right next to it the lawn still looks good. Can cold or lack of light form such spots?


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## g-man (Jun 15, 2017)

Do you have close up images from Nov? The problem started back then.


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## nwlawnguy (Apr 27, 2018)

I'm no expert by any means but it sort of looks like mine. I have RTF and every year in January it starts getting thin and brown but I attribute it to the rain and lack of sun in the Pacific Northwest (Oregon and SW Washington). I always fertilize in early March and again in early April and by mid April it really snaps out it and I have a hunch you will see the same after a couple of fertilizations.


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## ABC123 (Jul 14, 2017)

2L8 said:


> If it was just lack of light and cold, all areas should look the same, or those in the shade the worst. The left area on the second to last picture gets less light than the right one because of a building about 5 feet to the left (south is also left), but it looks better.
> 
> The reason for my assumption that it is a fungus is because of the way it appears as single spots, while right next to it the lawn still looks good. Can cold or lack of light form such spots?


it would all look the same if it was a monostand, a mix of cultivars and grass types is what your seeing.


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## 2L8 (Mar 18, 2019)

g-man said:


> Do you have close up images from Nov? The problem started back then.


Unfortunately no. The earliest close-up is from December, 15th.


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## 2L8 (Mar 18, 2019)

ABC123 said:


> 2L8 said:
> 
> 
> > If it was just lack of light and cold, all areas should look the same, or those in the shade the worst. The left area on the second to last picture gets less light than the right one because of a building about 5 feet to the left (south is also left), but it looks better.
> ...


However, the grass species and cultivars should be more evenly distributed. If the lawn is older, I can imagine that some tall fescue has died and been replaced by Kentucky bluegrass (TTTF/KBG mix), but these patches also occur in lawns that are only a few months old.

I wonder why the young lawn doesn't have problems with it yet. Possible reasons:

1. Young grass is more resistant to fungus, lack of light or cold. As far as light is concerned, this is probably true, as the grass shades each other less. Are young grass plants more resistant to fungus?

2. Young lawn dries faster because it is less dense. In the period when the damage occurred, it was very humid.

3. I avoid walking over the young lawn as much as possible. Maybe I spread a disease over the old lawn with my shoes. However, it doesn't look like the patches only occur where most walking is done over the lawn.

I guess I will have to send in another sample for analysis after all. Unfortunately, the test is quite expensive (about $50). Does anyone have any literature on how such an examination is performed?


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## g-man (Jun 15, 2017)

At this point, i would just spend money on seeds instead of testing. For next year, try to take more images early on so we can detect this sooner. Likely the fungicide in late November was too late in the season.

I'm trying to remember, you are close to hamburg in deutschland?


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## 2L8 (Mar 18, 2019)

g-man said:


> At this point, i would just spend money on seeds instead of testing. For next year, try to take more images early on so we can detect this sooner. Likely the fungicide in late November was too late in the season.


I have a picture of another area where it started later and is less developed.

Maybe the pathogen (if there is one) already gone and the grass is now slowly dying, but I never noticed anything else in these patches.

But wait, I took a picture of an area a week ago where a mycelium can be seen. I suspected mildew, because I had already seen mildew in this place (in the shade of a tree) in spring. Also now in other places there is a white mycelium that appears to be from powdery mildew.




g-man said:


> I'm trying to remember, you are close to hamburg in deutschland?


Close to Hannover.


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## SNOWBOB11 (Aug 31, 2017)

What's the shade/drainage like?


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## 2L8 (Mar 18, 2019)

The shadow is created by buildings and trees. The latter are now bare and shade less, but due to the low position of the sun, some areas are now permanently in the shade.

The soil is very sandy, with a relatively large amount of very fine sand. I had replaced the top approximately 2 inches in some areas with delivered sod with a high sand content, and mixed and applied delivered topsoil with additional sand in others.The 10 inches or so below that I had thrown through a sieve along with about 1/3 sand. 
I don't see any difference due to the difference in soils.

I think the problem is the leaf blades being wet too long rather than the wet soil. It could also be that the gas exchange in the soil is impeded, or there is a fungus in the soil.


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## SNOWBOB11 (Aug 31, 2017)

Like g-man said I think now you will just have to re seed the area. I think the problem could be the leaf staying too wet like you mentioned. If the area stays wet/shaded it could be difficult to stop this from happening again.


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## 2L8 (Mar 18, 2019)

I am slowly coming to the conclusion that I bet on the wrong horse with the TTTF/KBG mixture. TTTF seems to suffer in the winter and KBG the rest of the year. That is often affected by rust and powdery mildew. But rust I also saw on PRG in the old lawn.

Obviously, I don't have the fungal infestation in the lawn under control. Once it occurs, it keeps coming back. I would have to disinfect the whole yard to get rid of it.

If I knew what was causing the current spots, I could try to counteract it. One possibility would be to reduce the fertilization. Last year I spread a lot of N from March to November. Maybe too much, but the lawn looked good for a long time.


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## bernstem (Jan 16, 2018)

I wouldn't give up completely on the grass species choice yet. I don't know where in Germany you live, but KBG is native to the mountains of Europe. A couple possible issues you may have that can lead to disease:

1. excess shade. KBG and TTTF prefer full sun. The more shade you have (especially in the AM which allows the grass to stay wet longer from the night) the more it will struggle. 
2. excess moisture. See above. If the lawn is constantly wet, then diseases will run rampant. The moisture could be from watering too often, heavy soil that holds water, shade, etc.

My guess is you have one of those two problems. I would also look into the soil. You may have a nutrient or pH deficiency so I would also recommend a soil test. You will have to research where to send it in Germany.

I would also help if you can post some pictures of the entire lawn. That will help us with assessing shade, tree roots, etc.


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## LawnMavrik (Sep 22, 2020)

Looks like a moderate-trafficked section of a lawn I maintain that lays wet late in the growing season under a Katsura that apparently doesn't soak up enough of the moisture. I reseed it often due to the abiotic/hypoxic stressor until the drainage is fixed and shading from the tree is addressed. If you aren't already, focus on moisture management and the right grass in the right place.


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## 2L8 (Mar 18, 2019)

bernstem said:


> I wouldn't give up completely on the grass species choice yet. I don't know where in Germany you live, but KBG is native to the mountains of Europe. A couple possible issues you may have that can lead to disease:
> 
> 1. excess shade. KBG and TTTF prefer full sun. The more shade you have (especially in the AM which allows the grass to stay wet longer from the night) the more it will struggle.
> 2. excess moisture. See above. If the lawn is constantly wet, then diseases will run rampant. The moisture could be from watering too often, heavy soil that holds water, shade, etc.
> ...


I am aware that Kentucky Bluegrass did not originate in Kentucky, but in Europe and Asia and was naturalized to America. Likewise Tall Fescue, which originally occurred only in Europe. So climatically there should be no reason against these two grass species for a location in temperate Europe.

But the conditions in this garden are not optimal for grass. The soil is sandy and water-permeable, but only a few areas get much sun. On the other hand, there are steep slopes and in some places there is a concrete base 8 inches below the surface. This means that some areas dry out quickly in the summer. I've already removed some trees and cut others back severely, but I can't tear down buildings for better lawn growth.

In even more heavily shaded areas, where large plane trees from the neighboring property cast additional shade, I have established a Poa supina lawn that is doing relatively well there. For the other areas I had also thought of Poa supina. But even in the shade, this grass dries out relatively quickly, perhaps because of the sandy soil.

In the end, however, it would probably have been better to go completely for Poa supina and invest time in an irrigation system instead of wasting an incredible amount of time removing unwanted grasses and tilling the soil. However, since 2019 and 2020 were dry and warm, and even drier and warmer years are predicted for the future, I thought TTTF/KBG would be a better alternative.

The problem is probably due to water clinging to the leaves for too long. 

I have seen that you can strip the water quite easily with a leaf rake. It just means a big time commitment. For the current year, however, I will probably try this in parts.

By the way, I had also sprayed azoxystrobin on some sub-areas in early September and mid-October before the infestation, and tebuconazole on another sub-area in early October. Tebuconazole seems to have had no effect. The areas that were treated with azoxy look somewhat better. However, it is not conclusive, some untreated areas look the same.


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## bernstem (Jan 16, 2018)

If you have shade and the grass gets less than ~6 hours of sunlight per day it will struggle regardless of how much fungicide you throw at it. If you have to water often due to soil conditions, that worsens the issue as the grass never dries out. You can try improving the soil with organics which will increase water retention and reduce watering frequency, but your thought to convert to Poa Supina may be the best option. It is performing better in your lawn, after all. I would still strongly recommend a soil test before you do anything major. If there is a serious nutrient deficiency, then fixing it may be enough to allow the TTTF/KBG to do better. Even if you convert to Poa Supina, it will appreciate improved soil as well.

You almost certainly know this, but fungicides can be tricky to use. Disease ID is critical. If you know what diseases you have, then you can spray to prevent them which is much more effective. Even if you miss prevention, knowing what you are treating is important as fungicides only treat some diseases. Use the wrong chemical and you are wasting money.


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## 2L8 (Mar 18, 2019)

bernstem said:


> If you have shade and the grass gets less than ~6 hours of sunlight per day it will struggle regardless of how much fungicide you throw at it. If you have to water often due to soil conditions, that worsens the issue as the grass never dries out. You can try improving the soil with organics which will increase water retention and reduce watering frequency, but your thought to convert to Poa Supina may be the best option. It is performing better in your lawn, after all. I would still strongly recommend a soil test before you do anything major. If there is a serious nutrient deficiency, then fixing it may be enough to allow the TTTF/KBG to do better. Even if you convert to Poa Supina, it will appreciate improved soil as well.


The nutrients in the soil could be a reason, specifically a possible potassium deficiency. Thank you for reminding me. The last soil analysis is from September 2020, when I sent the sample to be tested for a disease. At that place there was a potassium deficiency, phosphorus was slightly above normal and pH was at 5.5. I then applied potassium as "potash magnesia". In another place, where I planned to renew the lawn, potassium and phosphorus were slightly above normal and the pH was at 7. There was still the unworked soil without additional sand.

I paid little attention to the additional potassium application in the fall, as I had not noticed any differences in tests the years before whether I had sprinkled potassium in the fall or not. But the last 2 years I often used urea instead of complete lawn fertilizer and so added less K and P .

I have already planned to send in more soil samples and am still thinking about where to take the samples, or whether I can at least determine the potassium content myself. Because of the different soils and the different infestation I would find samples from some places for useful.



bernstem said:


> You almost certainly know this, but fungicides can be tricky to use. Disease ID is critical. If you know what diseases you have, then you can spray to prevent them which is much more effective. Even if you miss prevention, knowing what you are treating is important as fungicides only treat some diseases. Use the wrong chemical and you are wasting money.


Identifying the disease is in fact the reason why I posted the topic. I have little experience with the application of fungicides. However, timing seems to be of great importance. Perhaps the current problem already goes back to a cause in the summer that I didn't recognize.

I would like to avoid the use of fungicides. If I understand correctly, here are even no fungicides allowed for the lawn.


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## bernstem (Jan 16, 2018)

You can post the soil test in the soil forum and get some more specific advice. With an image of the test it will be easier to give recommendations.

As for disease ID, it is hard to tell much months after the onset. Posting pictures when the lawn is first affected will be the best way to ID a disease. You want to post pictures of the lawn in total, pictures of the affected area, and close up pictures of the affected grass. Pictures of the roots can also help in identifying root diseases. You may also want to send samples to a lab again. They may be able to find something with another sample. There also is the possibility that you are currently dealing with winter damage and nutrient deficiency rather than a disease - I don't know how cold it is where you live and Germany is a big country with a lot of different climates.

I generally don't offer disease diagnosis over the internet as I am terrible at it. What I do see is very wet grass with leaf lesions. I think you really need to look at overall management including watering, soil, and fertilizing. I continue to think that you have a lot of shade (pictures of the overall property would help) and possible overwatering. At this point, I would wait and see what the lawn does in the spring when it warms up.


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## g-man (Jun 15, 2017)

I've been near your location in Germany and I know the weather, I do think that PRG would be a better choice than TTTF.


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## 2L8 (Mar 18, 2019)

bernstem said:


> You can post the soil test in the soil forum and get some more specific advice. With an image of the test it will be easier to give recommendations.
> 
> As for disease ID, it is hard to tell much months after the onset. Posting pictures when the lawn is first affected will be the best way to ID a disease. You want to post pictures of the lawn in total, pictures of the affected area, and close up pictures of the affected grass. Pictures of the roots can also help in identifying root diseases. You may also want to send samples to a lab again. They may be able to find something with another sample. There also is the possibility that you are currently dealing with winter damage and nutrient deficiency rather than a disease - I don't know how cold it is where you live and Germany is a big country with a lot of different climates.
> 
> I generally don't offer disease diagnosis over the internet as I am terrible at it. What I do see is very wet grass with leaf lesions. I think you really need to look at overall management including watering, soil, and fertilizing. I continue to think that you have a lot of shade (pictures of the overall property would help) and possible overwatering. At this point, I would wait and see what the lawn does in the spring when it warms up.


I sent in a soil sample for analysis 9 days ago. The processing time there is 2- 3 weeks. When I have the result, I will share it in the soil forum. The pH I measured myself (potentiometric, CaCl2). It is there at 7.4. At other places I have determined values from 7.4 to 7.6. Only the area less than 20 ft from the now severely affected area that looked bad in 2020 and better now has a pH of 6.

Because of the possible fungus I contacted the laboratory and sent photos and information. No fungus is suspected, but an abiotic cause. Due to the abundant N applications, the turf may have become too dense and soft and thus died during the cooler and colder seasons. But why so spotty?

I dug up a 4 by 4 inch area that was mostly bare, rinsed off the soil and tried to separate the roots. In addition to two clumps with a few green leaves, I found some small and larger root fragments, perhaps representing individual grass plants.



I planted these root pieces in pots to see if anything would develop from them. I don't see any new sprouting on the infested areas yet, but the healthy grass is clearly growing. It continues to be quite mild (around 10 °C / 50°F) and humid.


g-man said:


> I've been near your location in Germany and I know the weather, I do think that PRG would be a better choice than TTTF.


PRG may be better through the winter, but I also had problems with fungus (rust). My goal was actually to create a drought resistant lawn. PRG is probably not one of them.

The seed was partly contaminated with Lolium and maybe seeds of it were still in the soil, so I found it frequently in the TTTF/KBG lawn and pulled it out if possible. It made itself noticeable there by growing more vigorously and forming larger clumps. So I have developed an aversion to it.

I liked TTTF the best so far, but I probably should have gone by what survives best rather than what looks best. But you can't tell until it's too late.


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