# Yellow Spots Identification



## hammerhead (May 14, 2019)

Hi all,

I started having yellow spots in my lawn about 4 weeks ago and it seems go get worse and worse. I already had this last summer but it disappeared in the fall. Does anybody know what this is?

PS: There is currently a lot of sand in my lawn. I put down some sand this weekend, so do not get fooled by the yellowish/greyish general look. The issue are really the distinct yellow spots/stripes/arches.

Thanks for your input.
Here the pics:


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## hammerhead (May 14, 2019)

Could this actually be cat pee? Or would you rather think a disease?

Edit: From what I can find online it could be dollarspot, however i do not see lesions nor mycellium. Any thoughts?


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## hammerhead (May 14, 2019)

According to all my research so far, I personally think it is a *fungus*, possibly dollar spot.

Unfortunately I could not find any lab where I live where I can send some leave tissue for analysis, so for now i have trust my own identification 'skills'.

Last time i had the issue (whole period from late spring until late summer) some days of rainfall in late summer seemed to 'heal' turf. My course of action now is to try and water heavily this week in order to see if it gets better. I found out that dollarspot does like dry soil, so in case it really is dollarspot it might disappear or get better when the soil is soaked deeply.

Also, April was very dry so far. I cannot remember the last rain.

Nitrogen deficiency on the other hand is out of question as my turf got enough of it.

PS: BTW I'm still open for any hints from your side. Thanks.


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## g-man (Jun 15, 2017)

I don't think it is dollar spot. First you will multiple spots thru the whole yard instead of just one. If you post close up images, we could check for hour glass damage common with dollar spot.

In the third image, to the right i see a different shade of green, but with a very rectangular look. Is that a different grass type?


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## hammerhead (May 14, 2019)

Thanks @g-man !
Actually I do have several small yellow spots throughout the lawn. They then seem to grow together and create continues stripes/arches. Thode spots seem to appear overnight.

I will try to take some more pics this evening.

The light-green stripes in my yard come from the reflection of sunlight from my fence, which is partially glass, so no, no other grass type😌. I should have stated that in my initial post. I kind of knew this question would come lol.


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## g-man (Jun 15, 2017)

There are a few fungus that create a circular pattern. Summer patch makes a froggy eye, but it would be more typical in July. Yellow Patch and Fairy Ring could do it now. Have you notice any mushrooms growing near the arches?


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## hammerhead (May 14, 2019)

@g-man no mushrooms.
I took some more pics today. Btw there are not only arches, also just straight stripes. In the beginning all start as spots.

Here they are. Maybe they provide additional info to you. I also think I'm seeing some hourglass shaped grass blades. My non-expert guess is therefore still dollarspot, but I'm happy to be proven wrong as well.

Thanks and cheers!


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## g-man (Jun 15, 2017)

I see the hourglass in the 5th image from the top. But this is how it normally looks on turf. http://www.msuturfdiseases.net/details/_/dollar_spot_1/

What are the pebbles or rock I see in 5 and 9 image?

In the last image, It looks like yellow patch. I get this one in my yard. http://www.msuturfdiseases.net/details/_/yellow_patch_22/


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## hammerhead (May 14, 2019)

@g-man thanks.
The pebbles are just larger particles that were in my sand which I applied last Friday (0.5 tons/1000 sqft). There are very few of those and normally the sand is 0-2mm.

Fungus: I agree it kind of looks like yellow patch but compared to those pictures my arches seem bigger. 
I've also never seen very small circles the size of a key. Before the arches appear i only see spots, the arches are not there from the beginning on. Individual spots seem to create those arches/stripes over time.

Also the description of yellow patch does not quite fit. It says humid wet conditions etc, but here it is general quite dry and especially dry now (zero rain, sun, sometimes windy). Temps are around 20-24 degrees Celsius ATM (rather warm).

It somehow also seems that when i applied sand it got worse because i spread it all over the lawn with my level rake.


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## hammerhead (May 14, 2019)

After some heavy watering i can definitely see some new green growth coming out of the straw-like dead grass spots.

I was still not able to identify the fungus. I've read a lot about lawn diseases this weekend but there is really nothing that really fits the thing I have. @g-man was probably right in saying that it's likely not dollarspot, but I'm not very convinced by other things as well (my non-expert opinion keep in mind).

Will keep you up to date in case I can still find out what it is.
Thanks so far for all the hints.

*EDIT*: It might also be necrotic ring spot. Description seems more or less to hold up with the things and timing I have in my turf. Anybody who has dealt with it already? Here the description of necrotic ring spot: http://www.msuturfdiseases.net/details/_/necrotic_ring_spot_13/

Cheers!


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## hammerhead (May 14, 2019)

Last 2 days were less sunny and there was even a bit of rain. I also irrigated on at least 3 different days last week. Turf recovered really well, it's remarkable. Turf is growing like crazy now, cut on Sunday and today (Tuesday) i probably cut 2/3 off (heavily violated 1/3 rule).

My 2 cents:
- Fungus attacks roots, so they get very shallow. Any kind of heat stress or drought might then be seen immediately
- ...OR/AND fungus likes dry soil

Anybody else made similar observations?


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## hammerhead (May 14, 2019)

Hi all,

The yellow spots/arcs/stripes are still there. Sometimes there are more sometimes there are less.

*Weather influence*
It seems to get better when weather is wet (maybe due to faster recovery) and worse when it gets dry.

*Grass blade die back pattern*
The grass blades seem to die off from top to bottom.

*Areas affected*
Not all areas of the lawn are affected and some are completely untouched.

*Other things noticed*
I currently have a lot of ants in the lawn.
I frequently see a cat invading my garden.
Do you think these spots could be from ants or a cat?

Any ideas?

Here some more pics:


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## bernstem (Jan 16, 2018)

That is a weird pattern. It looks like the path a squirrel or rabbit might make wandering on the lawn. The grass lesions are indeterminate and could be chemical injury (cat pee?) or disease. Improving with more water may just be happier grass recovering. Have you tried any fungicides? If not it might be worth a single application to see what happens.


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## g-man (Jun 15, 2017)

Those last images look more like yellow patch or necrotic ring spot.

What fungicides can you get in Switzerland?


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## cleohioturf (Jul 20, 2020)

do you know if you ever had more trees in the area? Almost looks like roots starving the ground of moisture. Even after a tree was removed you might have roots left in sub base.

Throwing it out there as a possibility. Maybe you already mentioned you have dug down in all these spots? Seems like you have a bunch in random spots but I would dig down in some of the larger areas and see what you have below surface to rule it out.


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## hammerhead (May 14, 2019)

Thank you guys for the comments.
@bernstem. It does definitely not come from a squirrel or rabbit, those animals never come to housing zones here. We can only find those in the forest. I also think that more water just speeds up recovery and therefore dryness is not the cause of the yellow spots. Injury trough fert or herbicides can be excluded. I have not tried any fungicides.

@g-man . I am not sure about the fungicides. I know we as homeowners can buy fungicides for roses but i do not think there is azoxy/propi (I've seen that is what you guys use in the lawn) in those. Maybe I could find it via farmers supply store, but not sure if I need a special permission to buy those. In general I am not keen on using fungicides in my lawn, but if there is no other way I will try it as a last resort. However I do more and more lean towards a non fungus issue. After comparing countless images of turf fungus I really do not think there is anything that matches close enough, however I do agree with you that there are some similarities with necrotic ring spot.

@cleohioturf . There were no trees in that area. It was a field for cows and horses for decades. I took some soil samples (8-10 inches down) and I couldn't see nor feel anything suspicious.

*Question to all of you*: I am more and more leaning towards a non fungus issue. Have you ever heard of ants causing turf damage like this? I mean digging underground corridors could theoretically injure the roots i guess? I currently have a TON of ants in my yard, and they are mostly concentrated around the area where the yellow spots occur. It is a real invasion, i have never seen this before in my lawn. In some areas (more shady, less dry) there are no ants at all and also no turf damage at all. I've read some German resources and they were talking about ant damage in turf, however i did not find anything alike in English speaking resources (they only speak about damage due to the ant hills and no turf damage caused by underground corridors).

Thanks for all comments!
Cheers


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## cleohioturf (Jul 20, 2020)

ants will usually cause mounds, they wont feed on the grass but their tunneling can dry areas out.


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## g-man (Jun 15, 2017)

Damage at the tips normally means an issue at the roots. I would treat for fungus.


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## hammerhead (May 14, 2019)

@g-man thanks. Would you recommend azoxy or propi? Or both at same time? Also at what rate for corrective properties? I will have a look at what I can find.

Thank you

Here also two current pics:


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## g-man (Jun 15, 2017)

Azoxy. The rate will depend on what % you find.

The lines are so strange looking. It looks like vole tracks.


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## hammerhead (May 14, 2019)

@g-man thanks. It seems I will be able to find some Azoxy.

Yes it really does look like some kind of tracks and that's why I thought it might be something other than fungus. The strange looks do not match with any pics of lawn fungus I could find with a google image search.

Neverthless I will probably try out the Azoxy. Will keep this post up to date.


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## hammerhead (May 14, 2019)

@g-man @bernstem I am now pretty sure the yellow spots/tracks do not come from fungus. I have a huge amount of ants creating tiny mounds all over the lawn after irrigation, that's how I discovered i have an ant problem. I applied an ant killer product some days ago. The lawn is already looking much better. I guess the yellow spots/tracks come from an underground ant tunnel system.
@Green I've seen that you mentioned ant damage in the lawn in another post. Do you have experience with it? It is really remarkable what they did to my lawn and it seems to be a problem that may often be mistaken for fungus in other cases. I did not really find any English speaking resources talking about ant damage in the lawn (yellow spots). I am wondering if they also feed on the roots?


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## Green (Dec 24, 2017)

hammerhead said:


> @g-man @bernstem I am now pretty sure the yellow spots/tracks do not come from fungus. I have a huge amount of ants creating tiny mounds all over the lawn after irrigation, that's how I discovered i have an ant problem. I applied an ant killer product some days ago. The lawn is already looking much better. I guess the yellow spots/tracks come from an underground ant tunnel system.
> @Green I've seen that you mentioned ant damage in the lawn in another post. Do you have experience with it? It is really remarkable what they did to my lawn and it seems to be a problem that may often be mistaken for fungus in other cases. I did not really find any English speaking resources talking about ant damage in the lawn (yellow spots). I am wondering if they also feed on the roots?


Yeah. I had a spot a couple of years ago and it started getting bigger. I was like, wth is going on?? Then it happened the next year in the same spot. I saw carpenter ants, too. It was near a tree so that was not good. I stuck an ant bait near the spot. Within a week or two, the grass started recovering, because the ants were dead.


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## hammerhead (May 14, 2019)

Thanks @Green . Unfortunately i do not have a singly spot but many different ones forming track-like appearance. Those ants are just everywhere.

Will soon post some pics to show the recovery. Let's hope it won't come back anytime soon.


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