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yellow patch/cool season brown patch


I've been pretty quiet lately. No international adventure trips like John, no potpourri of diseases like Frank is seeing.

The most interesting thing is that there has been a little bit of yellow patch (cool-season brown patch). In Kansas, we most typically see this disease towards the end of winter, like in late February/early March (that is when the photo was taken). But, the pathogen (Rhizoctonia cerealis) can certainly be active at the temperatures we have been seeing lately.

One superintendent noted that he tends to see yellow patch more in greens that are primarily (>80%) Poa annua, not bentgrass. I have not noticed that myself but am wondering if others have seen the same trend.



Another interesting turf disease issue this fall is a tremendous amount of powdery mildew. The fungi which cause powdery mildew do not require leaf wetness, but they do appreciate some humidity. We've had a wet autumn, so that has probably increased the disease pressure. In some shady areas there's so much powdery mildew that it looks like someone sprayed white paint on the ground.

6 Responses to “yellow patch/cool season brown patch”

Frank Wong said...

What's that puddle on the upper right hand side of the photograph? Looks like pee patch to me.

TL@PP said...

We've seen a little yellow patch this fall. Our greens are primarily bent with some poa trying to move in. We've treated the worst spots, but I'm wondering if it will go away with the cold or go dormant coming back stronger in the spring?

Megan said...

I have not gone through a season where there was yellow patch in the fall--just late-winter. So, I don't have a gut instinct on what you might experience. Here in Kansas what we typically see is symptoms arising in late Feb and persisting through March or April, maybe later if it is really cool. I have never not seen it yet in the fall. Maybe one of the others can help predict what you might see. Where are you located?

Frank Wong said...

As far as I know - Yellow Patch can develop anytime you have max. daytime temps. below 65F. Fall/winter damage can remain present for al long time if temps are non-conducive for plant regrowth. Usually, warmer, dry weather results in it going away.

However... since we've seen some new Rhizoctonias emerging in the last few years - it'd probably be good to confirm the pathogen as yellow patch; brown ring patch (aka Waitea) can look very similar.

TL@PP said...

Brown ring was/is certainly a consideration. My identifying skills and resorces are limited. My background is in engineering (BSME K-State, 1991) but I have an opportunity here at my home town course. We are a small town 9 hole course in south central KS. It is a very nice track for the budget we have to work with. Megan, do you have any recommendations for local resources in the Hutchinson/Wichita area? Thanks for the responses!

John Kaminski said...

You could try to ID it on your own. Pull a plug (cup-cutter) about 2 inches deep and put it in a tuperware or similar plastic container. Put the lid on and incubate overnight (24-48 hrs). Cool temp doesn't produce mycelium like BRP. Check out the photo section to see some images of what you might see...
http://turfdiseases.blogspot.com/2008/08/brown-ring-patch.html

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