Early disease presence?

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lVlrBoJang1es
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Early disease presence?

Post by lVlrBoJang1es » June 1st, 2017, 7:20 am

We experienced a week of temperature spikes in my area (south east MI) not long ago - high 80s, low 90s. The month before, we had nearly non-stop rain. As of lately, it's been in the high 70s with rather high humidity (70-75% every day).

About a week ago, i started to notice "browning" in the lower 1/2 ish growth on of MOST of my lawn. The top growth remains green, but the under growth seems to be struggling with what i can only assume is the start of a disease/fungal issue.

From above, the afflicted areas show minimal damage (aside from a bit of thinning) since most of the brown is covered by the green top growth:
https://postimg.cc/image/syn19dmgz/

Once you expose the lower growth, you can see the browning:
https://postimg.cc/image/5huzp6zwb

Along the edging, you can see how it transitions from a non-issue-area of lower green growth (left of half of picture) to the issue-present brown lower growth (right half of picture). the top growth appears to be shade more yellow in the right side where the lower browning is present:
https://postimg.cc/image/arq11192t

Here you can see the edging that has the brown lower growth pulled back:
https://postimg.cc/image/t6992n0fx

From my initial inspection and research, i'm leaning towards:
Rhizoctonia blight
Pathogen: Rhizoctonia solani AG1-A, AG 3
Susceptible grasses: bluegrass, annual bluegrass, fescues, ryegrasses
Symptoms: first appears as small, irregular brown patches or rings that can enlarge to many feet in diameter; centers might recover resulting in rings of diseased grass; leaves and sheaths become water soaked, wilt, turn light brown, and die; in light infestations, roots usually not infected and plants often recover; soil-inhabiting fungus that forms fine, fungal threads in soil or on turfgrass
Conditions favoring disease: excess thatch and mat along with high temperatures (80°– 95°F); high humidity; soft, lush growth due to excessive nitrogen; most common in warm, inland areas
Prevention: reduce shading and improve soil aeration and water drainage; water appropriate length of time to a depth of 4–6 inches; avoid excess nitrogen; maintain thatch less than 1/2 inch
Chemical treatment: fungicide useful if disease severe in past or for seedlings in young turf
I applied my first app of Serenade concentrate at 4Oz/k before/right around the same time i noticed the issue. I don't see "Rhizoctonia blight" listed in the targeted diseases on the serenade label, but the label seems to use some "common" names rather than the scientific nomenclature... If this does infact target whatever it is that I have (still going to do more research for a positive ID) i'll probably change my plan to weekly apps rather than every other week.

Am i on the right track?

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andy10917
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Re: Early disease presence?

Post by andy10917 » June 1st, 2017, 8:48 am

I dunno, but I wouldn't rush to a conclusion (just stay vigilant).

In some years, many of us have healthy lawns that show brownish growth underneath the top growth, without specific fungal lesions - and it never spreads or kills. Half jokingly, we've called it "BBDL" (Brown Blades Down Low), and it generally seems to be a couple/few weeks after the Flush ends.

lVlrBoJang1es
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Re: Early disease presence?

Post by lVlrBoJang1es » June 1st, 2017, 9:23 am

Okay!

I searched around a bit, but obviously didn't pick the right words to punch in. I'm sure there are just short of a million different ways to describe the symptoms I observed, hence the wide range of irrelevant search results that were returned!

I'll continue my serenade apps at a preventative rate unless something looks to be developing more definitively. At that point i'll probably come back here with some pictures for further diagnosis.

Thanks for the reply Andy!

lVlrBoJang1es
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Re: Early disease presence?

Post by lVlrBoJang1es » August 1st, 2017, 8:16 am

Conditions have become alarmingly fungal promoting over the past week in my area. I'm about 4 days behind on my bi-weekly serenade apps (4Oz/K)...

The particular area mentioned above has definitely succumbed to a rust outbreak. I noticed this morning on my way to work - i'll post pictures today when i get home or tomorrow. The outbreak is not severe, but it sticks out like a sore thumb in my eyes.

I'd like to believe that i've been following reasonable irrigation and fertilization practices:
  • I may be going a bit heavy on the Milo for my lawn - still dropping about 0.5-1.5 bag rate every 2 weeks. I say this may be heavy in MY case since last year was the first year that my lawn has experienced any organic material applications.
  • I've been following my soil amendment recommendations.
  • Irrigation+rainfall has been kept at 1"-1.5" weekly. I've found that I need to spread this out between three waterings in the current heat to prevent my newly overseeded (fall 2016) blades from showing signs of heat stress.
  • Irrigation happens between 3AM and 9AM - maybe too early?
My understanding of rust (google-fu combined with what i've learned hear):
  • It favors areas deficient in nitrogen (weird in my case).
  • It favors areas that lack sufficient irrigation (also weird).
  • It likes to show up when temperatures move from hot-> cool. Temperatures have been pretty moderate and consistent given the time of year (see my log below).
  • It can be "pushed" off the grass by encouraging growth then (bag) mowing the affected blade portion (hopefully the irrigation and milorganite is enough growth encouragement)

    Logs of recent past:
    Image

    I'm debating on whether or not to just continue with the serenade apps, or spot treat this area with a chemical fungicide. We have some cooler weather coming up (no predicted highs above 80 for a week after thursday https://www.wunderground.com/q/zmw:48073.1.99999) but we do have some rain storms rolling through over the next day or two - this may make timing applications difficult if i don't act TODAY.

lVlrBoJang1es
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Re: Early disease presence?

Post by lVlrBoJang1es » August 18th, 2017, 12:47 pm

The day after this post i did some investigating and found... alarming results.

I prepared the following update a while ago, just didn't have time to get the pictures off my phone:

--------------------------------------------------------------

The rust is most concentrated in the area that this thread originally focused on, which i expected as it's the only spot with significant discoloration in my 4500 sqft:
Image

What i didn't expect was to find this stuff present in more or less my entire yard :shock: . I'd bet my life you could find a bit of rust present in every square yard of my lawn. Most of the outbreaks seem to be localized - only affecting 10 or so blades and surrounded by somewhat healthy looking grass. In most cases, I had to part the turf down to the soil to find it, but the rust was there along with some minor leaf spot:
Image

After my investigation, i applied my bi-weekly serenade app (5 days late). I think i'll give the lawn some time to sort itself out and hit it with serenate again in a week. I really don't want to break out the big guns (chemical fungicide) yet. Hopefully this doesn't bite my in the arse and i wake up to a cheeto powder colored lawn one morning... There was quite a bit of rust powder on my shoes after i completed the Serenade app.
Image

I'm not sure if this stuff was around last year. I'm guessing the rust was there, i just had so little actual grass in my yard (before i overseeded in the fall) that it probably wasn't as noticeable... That, and i hadn't been "bitten by the bug" at that point so my eye wasn't keen enough to identify a problem.
------------------------------------------------------------------

Since then, i've been bag-mowing and keeping up with the serenade apps. The area doesn't seem to be getting worse, though it also doesn't seem to be getting much better... The amount of rust powder on my mower seems to be decreasing a bit though.

I'm starting to question some of my practices that may have lead to this outbreak. This will be a good area to review my log and adjust during the 2018 summer period. :good:

Feel free to offer any advice!


greenrebellion
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Re: Early disease presence?

Post by greenrebellion » August 18th, 2017, 2:37 pm

Rust (outside of the aesthetic decline) isn't all that big of a deal even if left untreated. The quickest and best cure is nitrogen. So once weather starts to cool down for you, some nitrogen apps this Fall will get the grass to outgrow the rust.

lVlrBoJang1es
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Re: Early disease presence?

Post by lVlrBoJang1es » August 19th, 2017, 12:45 pm

greenrebellion wrote:
August 18th, 2017, 2:37 pm
Rust (outside of the aesthetic decline) isn't all that big of a deal even if left untreated. The quickest and best cure is nitrogen. So once weather starts to cool down for you, some nitrogen apps this Fall will get the grass to outgrow the rust.
Roger that.

I've been keeping up with my 1-0.5 bag rate bi weekly apps of milo, but i'm struggling hard to resist the urge to throw down the balanced 12-12-12 fert i have in the garage.

My soil amendment app schedule along with the lingering heat of summer leads me to believe i'm best off waiting until the last week of august/first week of sept rather than applying now in an attempt to flush the rust out.

I was relieved to see that the rust's spreading has been kept at bay by now and I have no doubts that it'll clear up once the chem fert goes down. Once timing is right, i'll also be trying out the fall-fert regimen which will undoubtedly grow-out the rust.

I still find it odd that i was hit with rust right in the middle of the summer heat despite what i've read about typical timings and rust promoting conditions.

lVlrBoJang1es
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Re: Early disease presence?

Post by lVlrBoJang1es » August 25th, 2017, 10:51 am

I've been hitting the entire lawn with Serenade weekly and continuing the bag mowing.

The areas that were struggling are starting the bounce back, but i haven't really noticed a decrease in rust buildup on my mower. I usually blow off my mower and store shortly after without paying TOO much attention to it - the rust powder very may well be residual from previous mows. I decided to power wash my mower after the last cut - i'll know definitively on the next cut whether the rust powder is starting to go away as i'll be now be working with a blank canvas so to speak.

Also going to drop down my balanced fert app today now that the high temps have dropped below 80 degrees in my area. I'm also due for some irrigation, so this timing works out nicely. From what i've ready, the stimulated growth from the fert app will help the turf "out grow" the rust.

I hope I can get this stuff under control in the next few weeks - i really wanted to play around with PGR in the fall and i've read that it doesn't mix well with rust (or any other disease for that matter).

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Dchall_San_Antonio
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Re: Early disease presence?

Post by Dchall_San_Antonio » August 28th, 2017, 10:55 am

What you have is not rust. Rust does not damage the grass. Rust sits on the grass like a dust and rubs off on stuff. Then it's gone and the grass is fine. If you are treating it as if it was rust instead of whatever it really is, you might be prolonging the issue.

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